'08 Hummer H3 Alpha build

[JPaul]

So here's the diagnosis. Lifter for cylinder 6 intake valve seems to have had something chew through it, probably a needle bearing, though I didn't notice any missing. So the lifter is shot as well as the camshaft.

Fortunately everything else looks OK. The pushrods look fine, as does the bore for the lifter. I pulled the rear 4 pistons out and the bearings all look fine and there is minimal scratching on the piston side walls. The cylinders don't seem to have any scratches in them that a hone wouldn't clean up, I couldn't catch anything with my fingernail.

All in all I think it's in great shape other than the lifter and the cam. I'm probably going to put a mild cam in to give it a little boost, seeing how I have to replace it anyway. New lifters and pushrods will be cheap insurance. I'm going to inspect the rocker arm that lifter mated with to make sure nothing went through it and chewed it up as well.

Hopefully I can get the rest of it torn apart, cleaned up, and then put back together in the next couple weeks. With how minimal the damage is I think it's definitely an attainable goal.

 

[Cpyonker]

So you had an alpha previously? What made you buy a new one?


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[JPaul]

So you had an alpha previously? What made you buy a new one?


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I did not, this is my first Alpha. My other H3 is just a base model with the 3.7 i5 and the only package it had added to it was the tow package.

This Alpha has the 5.3 V8 (since that is what makes it an Alpha), the luxury package (leather, nav, Bose audio system with subwoofer), adventure package (4:1 transfer, rear locker, 33 inch tires, different shocks), tow package, sunroof, etc. Basically the only package my Alpha doesn't have is the rear entertainment system. The previous owner added the front e-locker (2008 only had the rear locker, 2009-2010 added a front locker at the factory).

I bought the Alpha since the i5 struggles so much when loaded down with cargo and people in the mountains. It does ok for what it is, but the V8 makes a huge difference when towing. Max trailer weight for the i5 is 4500 lbs while the V8 is 6000 lbs. Plus all the offroad goodies it has will go a long way for increasing it's already great offroad capabilities.

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[JPaul]

Dropped the block and heads off at the machinist this morning, there are a couple deeper scratches in cylinder 3 but he thinks they should come out with a honing. Everything else looks really good, he's going to check the rods, polish the crank journals, clean and check the heads and face them, and install new cam bearings for me. I should have everything back by Thursday which means I can hopefully get the parts I need in by Friday and get the engine assembled on Saturday. Then I can start getting it all put back together next week and hopefully buttoned up. Worst case I think would be the week after that, so three weeks from now. That puts me at a week before my Colorado trip which should be enough to do the break in procedure and make sure everything is looking good.

 

[JPaul]

I picked up the block, heads, crank, and rods/pistons this past Thursday. Everything checked out ok and needed minimal cleanup. The scratch really isn't too bad, and the pistons are OK so I'm going to be re-using them as well. Next time around I might spend the time and money to build up a 6.0/6.2 and a beefed up transmission, but I do not have the time or money to go all out like that right now.

I spent all of Saturday getting the rest of the parts cleaned up in preparation for assembly. Cleaning pistons is the worst, though the front cover was pretty tedious as well, followed by the oil pan. I sanded the outside of the oil pan to clean off the corrosion and make it look a bit nicer. I still need to tear the heads back apart and finish up the cleaning on them, there is still buildup on the intake ports I want to get rid of. I'm also replacing the seals and springs so they need to come apart anyway.

I haven't ordered the bulk of the parts just yet, I wanted to get everything cleaned up and checked out before I pulled the trigger on my somewhat large Summit order I have built up. Still a few more things to figure out and add to my cart, but I should be able to get the order in later today. Then everything should hopefully get here by Wednesday or so to allow me to start getting the engine assembled. The transmission is ordered, but apparently there wasn't one ready so it won't get here until the 20th at the latest, it might arrive a day or two before that. That puts me a lot closer to my trip that I was hoping for, but it can't be avoided.

Major upgrade is going to be a Comp Cams XFI Xtreme Truck Camshaft 54-450-11. Should give a decent bump in performance without killing my bottom end. I was torn between that one and one from Cam Motion, but the lead time for Cam Motion is longer than I have time for right now.

Pretty much everything else I'm replacing is either a wear part or needed for the cam replacement/upgrade. One upgrade I was considering was a trunnion kit to replace the factory needle bearings for the rockers, but after looking into it more it turns out the upgrade kits are wearing out within several thousand miles due to improper hardening of the shafts. I could go with a bushing based trunnion upgrade, but I need to do more research on the longevity of them so I'll just stick with the OEM bearings for now. I can always swap them out later by just pulling the ignition coils and removing the valve covers.

 

[JPaul]

Heads are torn apart and cleaned (thank goodness I picked up that c-clamp style spring compressor a few months ago on a whim for a couple bucks from a thrift shop, it's made this so much easier than using the puller type), lapped the exhaust valves to clean them up (intakes are fine, and exhausts really weren't too bad considering the mileage, but still), and parts should all arrive in the next couple days provided Summit can get my order out the door. Bearings and assembly grease are coming from Amazon, but my plastigage is coming from Summit. I think I still have some left from my last rebuild, I'm just not sure where the red one is, I know I've seen the green around and that might be all I need. We'll see. I might be able to start getting the block assembled in the next day or tow, but I need to clean up the garage from tearing down and cleaning everything before I can start final cleaning and assembly of everything.

I'm still shooting for fully assembled by the end of day Saturday, but I have something in the afternoon onSaturday that's going to take up a good 4 hours of my time, so hopefully that doesn't set me back too much.

 

[JPaul]

A few developments. The transmission has shipped and will be here the 18th, so that's good. And Summit shipped my order today and it is supposed to get here tomorrow. Unfortunately the head gasket set I ordered off Amazon came today and it turns out it's the wrong one. The frustrating part is I used FelPro's lookup tool to find the right part number and it turns out they are wrong. They have the 2008 and 2009 model year H3's with the 5.3L using HS 26190 PT-2 and 2010 using HS 26190 PT-4, but they should all be using HS 26190 PT-4 which is for the Gen IV LS engines. HS 26190 PT-2 is for the Gen III LS engines and none of the H3's used those. Not sure why they did this, but it's pretty darn inconvenient.

The main difference between the two is the Gen III's didn't have the bosses for the AFM (DOD) and the knock sensors were located in the valley. The Gen IV's have bosses for AFM (DOD) but since the H3's didn't use this they used a different valley plate the blocked off the oil flow from those, and the knock sensors were moved to the sides of the engine, as well as several other differences from the Gen III's. So the gaskets for the valley cover are completely wrong in the PT-2 kit for the H3. If I can find some contact info for them I'll eventually reach out and try to get them to fix this. I should have paid closer attention to the picture of what was coming in the kit, but I never trust those anyway, and you'd think that they'd have gotten it right in the first place, especially after so much time since hte H3 Alpha's were released. I doubt I'm the first one to have this problem.

Thankfully Amazon had the PT-4 kit in stock and Prime so it will get here on Friday. I can at least get the bottom end all put together in the mean time and then Friday and Saturday finish off the top end. I'll still need to order pushrods after I verify the length I need, but those can be added last so it won't hold me up much.

 

[JPaul]

Checked clearances on the crankshaft last night, everything was still within production specs so I went ahead and did the final clean of the crank and journals and installed it. Next up is the camshaft and rods/pistons. I should be able to get those all checked and installed tonight, and if I'm lucky and have enough time I can get the entire short block assembled tonight. I was stressing out about my timeline before, but I feel a lot better now after being able to get the crank installed, even if I was up till midnight doing it. Even if I can't get the short block done tonight, I'll be well on my way to hitting my goal of getting it all back together by end of Saturday. Then it will be ordering pushrods and then next week will be re-installation.

 

[JPaul]

The weekend was productive, I was able to get the block assembled and the heads installed and pushrod length checked. Turns out I get to use stock length pushrods, but I'm going to go with brand new Comp Hi-Tech rods to make me feel better, plus I can get them quickly from Summit. I was also able to get the intake all cleaned up. So much crud ends up in there from the PCV system. If I had more time I would have soaked it for a few days in a tub of degreaser to get it fully clean, but unfortunately I don't have that kind of time right now.

The transmission arrived this morning, but since I also ordered some ARP flexplate and torque converter bolts with the pushrods I will not be bolting it up until tomorrow night at the earliest. That's OK because I still have some finish work to do with the engine and get the injectors soaking to clean them up a bit. I also need to modify my engine crane by cutting off most of the chain so that I can gain several inches of lift. It has about 8-10 inches of chain and a hook, I'll cut off the hook and most of the chain but leave a couple links and then use a shackle to attach my load leveler. This should give me all the clearance I need in order to be able to have the transmission and engine bolted together and then drop them both in at the same time. That will save me a ton of time and effort as opposed to trying to mount the transmission afterwards.

It's still looking like I might be able to get this all buttoned up by the end of this week. Here's hoping.

 

[AdvNerd]

Wow man, good thing you can do your own work. At least when this is all done you should have a very solid rig for the future. I had a 2008 H3 for a bit, loved it but the i5 got about 9 MPG around town and I couldn't keep it. Loved it while I had it.

 

[JPaul]

So, here's where I stood 16 days ago. Engine pulled and torn down, transmission sitting around being useless.

And as of today, I have the engine mostly back together (still waiting on pushrods and bolts for the flexplate) and the transmission arrived this morning. So much shiny. (Sorry, no pic of the transmission yet)

Today was spent pulling the oil pan for a second time (three if you count the initial tear down) to make absolutely sure I torqued all of the rod end bolts (I was 95% sure I did them all, but i didn't start marking them as done until after doing a couple already). The time prior was because I went to put the drain plug in and noticed there were still some metal filings in the threads in the pan, so it came back off to make absolutely sure it was completely clean.

I also got the valve covers on and the bolts finger tight, just to keep it sealed off until the pushrods come. Next up was pulling the rest of the parts off the old transmission that needed to be moved over to the new one and cleaning them all. Lastly I spent time cleaning out the engine bay in preparation for putting everything back together. (Un)fortunately while I was doing that I noticed the driver side axle's outer boot pull completely off the cup. From the looks of it this happened shortly before I got home, as there was some grease thrown around but it wasn't all of it. That's kind of irritating, but at least now I'm forced to swap out the bushings on the outer diff brackets with the Outfitter Design bushings like I was supposed to do anyway. Better get a new axle ordered since the ones I have sitting here are either already in need of repair or too stiff for me to feel comfortable using them.

 

[JPaul]

Daily update, mainly because I'm working on this every day trying to get as much done as possible. Pushrods arrived, got them and the rockers all installed and the valve covers on, along with the ignition coils and several various bolts threaded into the block (so that when I go to drop it in the right bolts are where they belong instead of me digging around finding them after the fact).

Cleaned up a bit in preparation for the install, also so that I could find all the bolts I've ended up scattered around. You'd think that after doing this so many times I'd have a box of ziplock baggies and a sharpie out there with me while tearing it down, but noooooo. "I'll remember."

At least a fair number of them I either threaded back into where they came out of, or took pictures of where they went in the block.

So I also spent some time figuring out what bolts went to where, and I have most of them figured out. Several are still a complete mystery to me, but I'm sure at this point I'll be able to figure it out as I put it all back into the Alpha. Because of this and some additional parts cleaning that I did, I didn't get to bolting on the flexplate and torquing down the balancer bolt. I did pick up a torque wrench from Home Depot that goes up to 250 ft/lbs though, my other 1/2" only goes to 150 ft/lbs and I've been having too many times where I needed more than that.

Tomorrow (Wednesday, since I'm posting this at almost 1AM, yay for long days...) I should be able to get the flexplate and balancer bolt taken care of, as well as prepping the transmission and probably getting it bolted up to the engine. Then hopefully I can actually work on dropping them into the Alpha on Thursday. Friday at the latest I think. Overall this has been going fairly well, so I think I'll be able to make it in time for my trip to Colorado next week. Big question will be if I can get enough miles on it for the break in process before we need to leave. I'll be doing a lot of driving around next week, that's for sure.

 

[JPaul]

Engine is all buttoned up and ready to be mated with the transmission. I cleaned up the half of the garage I've been working in (other side is still a disaster, don't judge me

) so that I could get the transmission prepped, also so that I could hopefully find the rest of the bolts...

Seems I have misplaced one transmission to engine bolt, and one engine mount bolt. I have no idea where they went, other than they probably rolled off somewhere, but I'm done digging around trying to find them. I'll pick up some replacements tomorrow.

I was able to get the new transmission out of its shipping crate and onto the jack in preparation for being bolted to the engine. I didn't want to spend money on a transmission jack so I made a platform for it out of some scrap plywood and 2x4 I had that happened to be just the right size and bolted it to the pad of the jack. It works pretty well really for what it is.

Old transmission is now drained and sitting in the shipping crate to be returned to Street Smart Transmissions (who I purchased the reman from, $1400 shipped which also includes shipping the core back, not too bad I think)

One other thing I forgot to mention yesterday was I took the fuel injectors out and had them properly cleaned and tested to make sure there weren't any issues with them. Even though the engine ran fine previously, if I'm going to go to all this effort to rebuild the engine and replace the transmission, I might as well make sure the fuel delivery is freshened up as well, 160K is quite a few miles for injectors to go without a good cleaning, especially when you don't know the quality of gas that was used in it. Cost me $180 for all 8 injectors, but that's cheaper than buying new ones by far, and they had them ready that same day. The flow rates before the cleaning were 11% down from rated at best, with some as bad as almost 16% down. Not to mention the spray pattern was only fair. Now they all flow at rated and are equal with each other, and the spray pattern is back to where it should be. This will not only help my fuel economy, but my power as well. Definitely worth the extra money in my opinion.

Here's where everything sits as of today:

My plan for tomorrow is to get replacements for the missing bolts, then go ahead and mate up the engine and transmission and get them dropped back into the Alpha and start the process of hooking everything back up. There seems to be light at the end of the tunnel finally.

 

[JPaul]

And it's in!!!!!

Thanks to some help from my wife, I was able to get the engine and transmission back into the Alpha tonight. I did bolt the transmission and engine together and installed them as one unit. It was a bit touch and go at a few points, and I had to pull the passenger side engine mount back out to give myself more room to coerce the engine into place, as well as use an old cookie sheet to protect the AC condenser from the balancer pulley, but overall it went fairly smoothly. I think next time I do this I'll wait to install the balancer pulley, that made it a very tight fit getting everything down and into the engine bay and tunnel. I still would need to remove the passenger side engine mount, but that one is easy to get to for re-installation, the driver side is a no go due to the steering shaft.

At first though I was going to try to push the crane with the engine/transmission out to the driveway to put it in, but since my driveway has an incline I was worried I'd end up wrecking something or hurting myself, so I used my red H3 to push the Alpha back into the garage. I put my pintle hook into the hitch on the Alpha and that gave me enough clearance to not hit the spare on the rear door, and the pintle hook lined up with my front bumper on the red H3, so it was a pretty simple matter. I'm glad I did it because it was a much more involved process to get the engine/transmission to drop into the Alpha, even with the load leveler. Once the engine/transmission were in and the engine mounts bolted up and the transmission crossmember temporarily installed I was able to roll the truck back out of the garage and park it in the driveway. I just don't have enough room still with all the tools and parts and old transmission to be able to leave the Alpha inside.

Overall though I'm glad I did them together instead of installing the transmission after the fact. Next up is getting everything bolted back on and hooked back up and then fluids put in and finally starting it all up and taking it for a drive. I'm pretty sure I should be able to get everything all done by end of day Saturday, including replacing at least the driver side axle that the boot popped off of. But seeing that engine and transmission sitting in the Alpha made me very, very happy. It's probably the biggest milestone aside from starting it all up and driving it.

 

[JPaul]

IT LIVES!!!!

Spent most of Saturday getting everything put back together, and I managed to get it completed enough to be able to put fluids in the engine and transmission so that I could try starting it up. Turns out I need to get a new battery, even though the battery has been completely unhooked during all this (and it was only maybe a few weeks or so) it discharged enough that I wasn't able to crank the engine long enough for the fuel to pressurize. Seems the H3 doesn't kick the pump on just by flipping the switch to "ON" like most cars do, or at least mine doesn't. I tried purging the air (and any dust that might have gotten in) from the fuel line before hooking it back up to the fuel rail, but we had to actually crank the motor for anything to flow. Fortunately my jumper cables are long enough to reach from the front of the Alpha all the way back past the rear to reach the front of my other H3. It had to crank a bit longer to pressurize the fuel system, but once it did it fired right up! Guess I'll be replacing the battery before the trip as well.

When I filled up the oil I also put a quart in through the oil pressure port in the bypass plate I installed. I figured out a neat and cheap way of doing this. $5 for a 1 gallon garden sprayer at Walmart and a 1/8" NPT to 1/4" barb gave me a nice little pressurized oil primer/filler/thing. It worked like a charm, and I'm going to use it to fill my transfer case as well.

Here's where it sits now, pretty much everything installed except the driveshafts. And I still need to swap out the driver axle.

I should be able to get everything else buttoned up on Sunday and then take it out for a test drive and to start the break in process. Oh, and I found the missing motor mount bolt, it tried to roll away under my lawnmower. And it turns out I actually didn't lose one of the transmission bolts, there was just one that was shorter than the rest that went on the bottom into the oil pan next to the filter. It's shorter than the others so that it doesn't stick clear out to where the filter sits, I swapped it in tonight as well.

I do still have one last bolt that I have no idea where it came from, but I've been through pretty much everything and didn't notice anything it could go to. I don't think it was anything super important though, at least I sure hope not.

Well, this saga is almost come to an end. Thanks everyone for watching.

 

[JPaul]

Finished up getting everything hooked up with the drivetrain and the oil pressure sensor. I have a pretty ghetto temporary solution in place for mounting the gauge in the cab, I'll take some pics tomorrow. Before I replaced the axle I took a drive around the neighborhood just to make sure everything was working OK. Max speed is 25 mph in my neighborhood so nothing was going to happen with the axle.

After getting the axle replaced I set out to take it for a test drive and to start the break in process. I only got maybe a half mile away before I realized I had forgotten to tighten the brake caliper bolts after I replaced the driver axle. Oops.

Got back home OK and torqued them down. Something I've been doing with all the critical bolts on this rig is marking them with a paint pen to be able to identify visually if anything is coming loose. This is now especially important to me after determining what it was that caused the outer CV boot to pop off the driver front axle. Turns out one of the bolts for the wheel bearing unit had backed out and ended up hitting the clamp for the boot and popped it off. After cleaning up all the grease and getting everything back together, I torqued that bolt down again and checked all the others. Unfortunately all of the bolts for both wheel bearing units were not fully torqued down, which is a bit scary. I'm glad I caught this before anything really bad happened, like losing a bearing/wheel on the highway or something. So those bolts are also marked with a paint pen so that I can make sure they don't come loose later.

So, after getting the brakes torqued down I set off again for a test drive and to start the break in process. Stopped in a church parking lot to check the fluid level of the transmission which turned out to still be quite low. I knew there was a little bit left in it from when Street Smart did their testing/break in, and I added about 5 quarts to get it started off. My driveway is on a slope though so I couldn't check the level properly, and my garage is now full of my engine stand, hoist, old transmission, and all my tools I've been using. I had the remaining transmission fluid with me (along with coolant and my garden sprayer/oil filler to top off the transfer case) so I put that in but it still was barely registering on the dipstick.

Headed over to ORielly Auto (tried Autozone first, they were already closed since it was 9:30pm by this point) and picked up a couple more quarts of transmission fluid which was enough to finally get the level topped off. I also topped off my transfer case while I was there. Then I headed out for the rest of the drive. I ended up putting almost 50 miles in tonight and everything went really well. Well, except for halfway through when I started hearing a scraping sound that was speed dependent. Since it was speed related I was relieved it wasn't the engine, and I was pretty sure it wasn't the transmission. I found a parking lot to stop at and took a look around. It turned out to be the brake disk shield which had apparently gotten bent when I was swapping the axle earlier, and it had warped enough to start rubbing against the brake disc rotor. Thankfully I at least still had a multitool in the truck with me and was able to use the can opener to pull the shield away from the disc. After that the rest of the drive went without any issues.

It drives great, and the transmission shifts wonderfully. My old one was definitely developing some issues so I'm glad I went ahead and replaced it. Only things left now are to get some temporary wiring in place for the oil pressure gauge (right now I'm just jumpering it to the battery terminals) and drive it a bit more and then do an oil change on it. That should get me through until we get to Colorado, then I'll change the oil again while I'm there, then again when we get back home. That will fully complete the break in process and I can switch back to Mobil 1 for my oil (you're supposed to use conventional oil for the break in to make sure everything mates up correctly and to avoid the cylinder walls glazing over).

It's been a long and tiring and somewhat expensive process, but this rig should last me a long time now. After my trip I can go back to trying to get it all set up for overlanding/camping.

 

[JPaul]

Scheduled the pickup for the old transmission, got the carpet put back in (the floorpan/tunnel gets bloody hot when driving around for a while, especially now that the weather has gotten warmer), and got the transmission loaded into the back of the Alpha to take to work with me tomorrow for the pickup. They charge an additional $200 if it's delivered to a residential address, so forget that.


Had some weirdness with the starter a couple times today, it sounds like the solenoid isn't staying engaged fully. I'm not sure if it's me flipping the key back too soon or something else going wonky. I'll keep an eye on it, I know the start was replaced just last year so it shouldn't be going out already.


This morning before work I also picked up the trailer tongue bracket I had welded up and got it painted tonight. I still need to cut the old ball tongue off and get this new one mounted. Once that's done all that will be left is bolting the truck topper onto the trailer and I should be all set for my trip.

 

[JPaul]

So, no, I didn't die on my trip to Colorado. Though a deer did. Tragic.

[VIDEO]
The irony of that was just minutes before it happened my wife and I were discussing what would happen if we hit a deer, since we had already seen quite a few along that stretch of road. She was convinced it would be very bad, I was (mostly) sure the truck would be fine. Fortunately I was right. The worst of the damage was my front spot lights ended up getting their brackets all bent (fixable, but even still they are a $20 pair off Amazon), the fairlead mount on the bumper was pushed back (fixed with a prybar), the top of the winch contactor housing was cracked open (still need to replace that) and my grille had all but two of its mounting points broken. Fortunately the two that are left are sufficient for now until I can replace it. That's really it. Thankfully I had the side bumper pods from Thorparts which helped greatly with protection.

 

[JPaul]

So, a lot has happened since I left for Colorado. The trip itself was good, even with hitting the deer, though I could have done without having to do so much remote work for my company during it.

Aside from the deer hit, the drive was unfortunately eventful. As I neared my destination I started hearing a tapping noise that grew louder and louder, and I started to notice a definite drop in power. Terrified something was going wrong with the engine, I pushed on and made it to the campsite my family was staying at. The next few days I drove the truck a couple times and while the tapping was still there, it wasn't nearly as loud as the first day. Then came driving from the campsite up to Colorado Springs. Again as I neared my next destination (my parent's house up a canyon south of the Springs) I was suffering terrible noise and power loss, and my engine was starting to get decidedly hot, but not quite overheating.

The next day I drove into the Springs to get some tools I hadn't brought with me, namely a mechanics stethoscope. I listened to the engine and couldn't find anything really wrong with it, the noise didn't appear to be coming from inside. Considering I just rebuilt the engine due to a trashed lifter I was obviously terrified I had done something wrong. The overheating was a real concern and the only thing I could think of was that it was the fan clutch since it really only got hot while driving slowly after driving at high speeds for a long distances. So I replaced the fan clutch and I might have also replaced the thermostat, I can't really recall if I did that during the engine rebuild or not, but probably during the rebuild.

That unfortunately did not seem to help much, so I just kept a close eye on it for the rest of the trip. On our way home from Colorado I started noticing that the tapping sound only was audible when I was accelerating, if my foot was off the gas you couldn't hear it. I knew then it wasn't anything internal since you would always hear the tapping, even if it was quieter with no load. The realization finally came that it must be an exhaust leak. We stopped at my sister's in Castle Rock for the night and I checked the bolts on the manifold and couldn't find anything loose. Then I checked the bolts from the manifold to the exhaust pipe and sure enough, the nuts had come loose. I tightened them down and that helped considerably.

 

[JPaul]

We made it back home the next day without any further issues, though that exhaust leak would continue to be an issue as the nuts kept coming loose. So imagine my frustration when it finally got to the point that no matter what I did the leak wouldn't go away. I kept checking the nuts but I finally had them permanently tightened so it wasn't that anymore. I then figure the noise was due to the doughnut gasket having become damaged or something. Finally about a month ago or so I was driving to work and went to pass some slowpoke and after accelerating hard my truck started to make a terrible racket. At first I was afraid it was the transfer case or something, but when I pulled over and got out to check, I realized it sounded more like a Harley. Looking down into the engine bay I noticed the insulation on the firewall was blowing around, and realized it was an exhaust leak. I couldn't figure out how it was leaking so badly, until I got underneath to try and get a better look.

Yeah, that shouldn't be just hanging there like that.

Turns out the threads for the O2 sensor had gotten buggered up somehow and it finally just blew out, though initially I thought it had just backed out somehow. I just happened to have pulled over just a few hundred feet from a NAPA so I drove over and borrowed some tools from a nice bloke that was also there to pick up some parts and that's when I learned the threads were damaged when I inspected the sensor more closely. Unfortunately I didn't have my own tools with me as I had been planning on doing the electrical to the rear and had the back all empty.

So I bought a new sensor and tried to install it, just to find the threads on the bung were buggered up as well. So then it was over to Master Muffler (which was also fortunately very close by) and left it with them for the day to repair the bung and get it all put back together for me. I just wish I had noticed it when I had the engine out as it would have been a lot easier and cheaper to fix it then. But hey, at least now I know why I continued to have an exhaust leak. Now it's much, much quieter and the power is back to where it should be. It's amazing how much an exhaust leak can wreck your power levels.