I haven't checked if there are pending codes. Considering how the problem is constant & has been going on a while, by now, I should be throwing codes left & right. At least I'd think so.

The engine itself runs great. While this could be a problem in the future, I don't think it's what's going on now. I will keep it in mind & bring it up before they do the work on the H2. A quick check won't hurt. I really should get an OBD2!

I'm just waiting on a few more parts to come at this stage.

 

Finally, I got the H2 back from the shop. Here's what I've learned & what the current state of the H2 is in.

The torque converter is almost impossible to get.
Autozone doesn't list right part (it points me to the torque converter for the 4L80e). Ended up spending $650 alone on the torque converter. FML. The issues I was experiences with acceleration seem to be gone. It was going, so it had to be done.

The flexplate was not cracked at all. Thanks for the idea, tharber. I was really hoping this was the cause. I can post a pic if anyone's interested. There's no cracking or anything wrong with the plate. It was still worth replacing it, considering the amount of time it takes to drop the tranny.


The shaking still persists. It's a hair better, but in no way acceptable. The mechanic says he doesn't notice it. I like the guy, but he's full of sh*t.

In park, the vehicle still shakes/vibrates all the (all tires), but when the AC kicks on, it shakes more. The shaking/vibrating isn't constant per say. It ramps up & ramps down, depending on the engine & the AC compressor. One the AC kicks on, the vibrating increases.

Also, I feel major vibrating under my feet when going from 55 to 60 mph. You can hear a drone from the engine while this is going on. It's not engine mounts or transmission mounts. They've been replaced. Other than doing a full power train gut, I'm perplexed. There's more to it, but it's hard to write it all down without making an annoying wall of text no one wants to read.




Does anyone's steering wheel shake in park/netural?
I want to start there. If I can figure that out, I might be able to figure the rest out.
As I've said, my 2003 H2's steer wheel never vibrated, but I want more input.

 

I had a 1988 GMC Diesel Suburban that had the shake that you are writing about that was never diagnosed proper and as a result, was never resolved. On the highway, the entire dash, glove box, center console between the two front captain seats, steering wheel, floors, etc...would shake like it was going to rip apart and disintegrate. I know how frustrated you must be.
Do you see the engine vibrating excessively while idling with the hood up? It could be the crankshaft, engine mounts, warped driveshaft, et al... You have a very special, hard to find H2, so it will be worth getting to the bottom of it. Have you taken that mechanic on the road with you? Have him drive it with you in the vehicle. Do you have a warped wheel or several warped wheels? But then again, you mention it increasing with the AC compressor coming on... You need a top notch diagnostic guy on your side here. By the way, has your H2 done this from the very beginning? If not, when did you notice it started?

 

I'm glad to hear it's not just me with the issue, but, yes, it's really frustrating.

There was a small period of time where the engine shook like hell (I think that was after having the motor mounts replaced). That's when things got really bad. Then the symptom of severe shaking would come & go.

All mounts are new (engine & tranny), so I don't think that's the issue. The other ones were pancaked.

Warped wheels wouldn't matter. It still happens in park/neutral. Tires aren't the issue either. That's what the the mechanic falls back on because I don't think he can diagnose it at this point. It's not wheels/tires, period. I could put it on a jack stands & take the wheels off, it'll still do it.

One thing that I find odd is that the faster I go, the symptoms don't get worse. The shaking/vibration is always there. I get more reverberation from 55 to 60, but it's not as if the overall vibration goes away, it's just worse in that part of the power band. I took the H2 up to 85 yesterday & it accelerated even better w/ the new torque converter (it was going, so it's good that I replaced it). But, it wasn't unstable at that speed or anything else. It's just that everything is slightly shaking. This makes me thinks nothing is really warped. Again, I could be wrong, but something that rotates & it warped would show worsening symptoms at higher RPMs. I'm not seeing that, even when the vehicle goes into overdrive and hit 4000 RPMs before shifting.

Honestly, the guy I'm working with is the "best" I can find around here. Sad, I know. He's continually denied that he feels the steering wheel shake. It must be something mechanics do when they can't diagnose/fix a problem. He's usually an honest guy, but it pissed me the hell off. I've never been in a vehicle where the steering wheel or anything else constantly vibrates. I'm just shaking my head.

I originally bought the H2 w/ the idea of putting a duramax in it. What I'm hoping is that the issue sounds power train related & a full gut will fix it. I just don't have the ability to do the D-max now, so it forces me to fix serious issues like the torque converter.

I won't get rid of it. I agree, it's special.
Other than small fixes, I don't want to put another cent into this power train. That can go towards the D-max.

 

That fact that it happens in park/neutral and gets worse when you put the AC on and cycles from bad to worse is mystifying. Someone out there will have the answer, I'm sure...but this isn't for the novice or intermediate mechanic. There are very few out there who are "great" mechanics. I have one here in the Detroit area...he's a Lithuanian guy and people ship their cars from all over the country to have him fix them. Mostly a Volvo/Mercedes/import guy, but he works on everything that looks like a car. Very honest, very reasonable with his pricing.
Regarding the Duramax...that is the engine these H2's should have had from the get-go. That diesel engine will be the ****e in your Hummer. I might do the same thing too, one day. How much are they in the crate? Is that how you would buy yours?

 

Yeah, the AC cycling on & increasing the vibration is nuts. I've done it so many times, that I know there's something going on there. As to what, I'm lost.


Yeah, the duramax is the best solution. I agree, the H2 should have been a diesel from the beginning. The hate for the low mpg (which isn't really that low & on par w/ vehicles of the time) was unwarranted & yellow journalism. Higher MPG would have saved the brand. It's really sad.

There's a few groups that do conversions. H-Line & Mash Motors are the two I'd avoid at all costs. I mean to the extent that I'd find another gasonline engine & gut the power train vs getting one of their frankensteins. Predator has been doing them, but some of their business practices are a little shady. That's the impression I've gotten from speaking with a few people who've dealt with them & their upselling practices, along with insanely higher prices. Duraburb seems to be the idea conversion shop & their prices are fair.

No one offers a crated Duramax conversion. You can do it, but is at least 1.5x the cost ($30k+ to closer to $50k) The engine & transmission would cost as much as a used power train plus the cost to do the conversion. I was originally under the impression that a 100k+ mile engine woudln't be a good idea, but when you're getting 500k to 1M miles out of an engine w/o major overhauls, 100k isn't a lot, especially with a warranty.

 

While really cool, that is just crazy money. It is really hard to justify putting that kind of money into an H2 unless it is really mint and has no salt exposure. I suppose these vehicles will eventually get to the point where frame off, nut and bolt restorations...just like the 60's muscle cars.
Sad that the entire Hummer line was so poorly marketed by GM. The media craziness and nutty lefties really killed this unique and beautiful truck. I have relatives that stopped talking to me and refused to get into my Hummer! That is why I no longer talk to them.

 

Man i'm racking my brain wishing I could help you some. You don't think that something exhaust related is somehow rubbing on the frame or body somewhere do you?

The duramax is the way to go, but that's just my opinion. With gas being so low right now it is hard to warrant that big of an expense. But it all depends on what you do with your H2. If you do a lot of towing, etc... than the cost becomes more justified quickly.

I had a V10 TDi Touareg that I loved and would tow anything I put behind it, but was too small for my growing family, hence the switch to the H2.

I am going to do some mods to the Duramax before it gets installed like the alternate fire cam, rods, coated pistons, bearings, and cylinder heads, etc...
I am also like Treviso mentioned going to do a little restoration to the frame and suspension while the body is off. Any rust will be treated, and then the entire frame is getting painted with POR-15, and all of the suspension components are getting replaced. It's so much easier to do this stuff with the body removed, and to me makes sense and I plan on keeping the H2 for a long time.

Speaking of which anyone have any feedback on the redhead gearboxes?

Synthetic, where are you located? If your somewhat local to me, i'd love to help you out...

 

Gas will go up. I'm not worried about the low price now. It's just a ping on the radar & nothing more, unfortunately. At the same time, diesel is cheap & the MPGs of either a 450hp or 600hp build are better than what the 6.2L does w/ a very light foot.


I've already rebuilt the suspension. It does not ride as smoothly as I like, but I think most of it is due to the engine being out of wack. Kind of like trying to hold a gyroscope in your hand & tilting it, except on a much larger scale. That's why it's so hard to tell what's up w/ the vehicle. Bouncing anything that rotates while unbalanced just amplifies the force. I have no way to gauge if some of my issues in "harshness" are in the rear end (trailing arms would be my guess) or if it's body mounts (doubt it, but you never know) or something else.


I'd like to get the frame coated while the body is off. I actually looked into the option of an entirely new frame (I have no clue what the labor cost would be), but they only run $1500. I will look into POR-15. Thanks for the advice.

My suspension is totally new. In no particular order:
1. New UCAs
2. New upper & lower ball joints in front
3. New shocks (custom adjustable king shocks w/ res)
4. New anti-sway bars & endlinks (front & rear)
5. New trailing arms (all 4 + pan hard bar)
6. New bump stops
7. New pitman & idler arm
8. New tie rods
9. New Idler arm support (not installed, but will have them do it)

I think you get my point. It's basically brand new.


I've heard nothing but good things about redhead gearboxes, but I don't have any knowledge first hand.



I'm just out of New Orleans. What about you?
I plan on meeting up with flyday58 in the next 2 weeks to see how his is running. He has an 08, like you do, so the power trains are the same.

I quickly took these two videos today of the engine running harshly (the vehicle was shaking so hard, it was audible in how it resonated). I will take a longer one with a go pro so I can record it while giving the engine gas. I'm under the impression the torque converter was a total waste of money. I do have a used, but perfectly fine flex plate if anyone's in the market! I can hook someone up for half price!

Here's the two videos.

 

Sounds like you have the suspension aspect covered

On the frame, as long as your isn't rusted through anywhere (which it shouldn't be in that part of the country) I would just use a wire wheel to remove any rust down to the bare metal.
Next use Rustoleum rust converting primer on the bare metal, and rest of the clean frame. You can get the Rustoleum at Lowe's
Then once that is dry paint it with the POR-15. If done properly that stuff is tough as nails. I used it on my car trailed and it has lasted through many things being drug on and off of it.

I'm in Pennsylvania so too far away to help unfortunately, man that sucks.

I have HP Tuners so we could've monitored some parameters in the engine to see if maybe it is one particular cylinder that's giving you the shake like maybe from a loose intake manifold that's allowing unmetered air to come in. Or any other number of things. But with that tool you can monitor all kinds of cool stuff.

I'll check the videos out tomorrow and let you know if anything pops into my head