I was curious if an Aisin AR5 out of a 2006 H3/Colorado is compatible with a 2007+ H3? Would this effectively be a one-for-one swap, or would this require any sort of modification?

My transmission (while still drivable) is starting to make some pretty gnarly gearbox chatter & occasional grinding sounds (especially when cold), and I'm in the early stages of looking for a replacement. I cannot find a shop in my area that can confidently say "Absolutely I can rebuild it for you" as most either simply say no, or tell me it is dependent on parts availability depending on what they find wrong inside the transmission. I'd really like this vehicle to last, so I'd prefer a rebuilt or a remanufactured unit.

I searched on Reman-Transmission.com and they appear to have a 2006 model in stock but are "out of stock" of the 2007+ models, which I found odd because I was under the impression they were effectively the same transmission, with the 2006 years having just a slightly smaller clutch than the 07+ models. Before I potentially spend thousands of dollars on a Remanufactured unit, I wanted to make sure the two are 100% compatible with one another and that there were no hidden easter eggs between the two of them.

Other options are to rebuild my existing unit myself (which I'd rather not do if at all possible) or buy a used unit online; most of the used 2007+ models I've found are in the 130k+ mile range, and most of them I cannot find the history of the vehicle which they were on.

Here is the ad for a 2007 Transmission (currently out of stock): https://reman-transmission.com/trans...h3/2007/manual

Here is what I am showing for a 2006 Transmission: https://reman-transmission.com/trans...h3/2006/manual

Any help is greatly appreciated!

 

I never looked into it, but I "assumed" they were the same. Yeah, I know, that provided absolutely zero help, but I am not going to dig into that one since I will never need it.

 

In case anyone is looking for a replacement in the future.

I just swapped my old 2007 AISIN AR5 out of my H3 with a Rebuilt 2005 Chevy Colorado 2.8L AISIN AR5. My old transmission still worked, but it was beginning to get pretty noisy, especially in 5th gear. Additionally, it had a considerable amount of FWD/AFT play in the output shaft; and the input shaft made a considerable amount of noise when spinning with the vehicle in neutral. Upon removal, the input shaft bearing seems completely shot, as there was a lot of "roughness" when spinning the shaft by hand. All in all, it seemed to be in need of at least a new set of bearings.

I got a very good price on the Rebuilt transmission from a transmission shop on eBay (if anyone wants the exact name of the shop, DM me; they still have 1x AR5 for sale as of writing this).

The Rebuilt Chevy Colorado AR5 was, in every way shape and form a 1-to-1 swap. No weird "change this, change that, etc."

I used an EXEDY 10-7/16" clutch kit GMK1028 26-Spline from RockAuto. 10-7/16" is a slight increase in size compared to the stock 2007 3.7L I-5 clutch. This kit comes with the clutch, pressure plate, clutch alignment tool, and a new input shaft bearing. Not bad for 139 dollars!!!

I did not take my flywheel in for resurfacing, but I did hit it with some 80 grit, 120 grit, and then 220 grit sandpaper to knock off the rust and at least smooth out some of the small imperfections in the flywheel. The AR5 bellhousing is not a fully sealed unit like the automatic transmissions are, so I'm thinking in one of my (very minor) offroading adventures, some small rocks/dust got kicked up and may have gouged the flywheel.

I am currently using Redline MT-90 GL-4 Transmission Fluid in this new transmission which (so far) has not provided any issues with shifting. I previously used Valvoline Synchromesh GL-4 in my old transmission, which overall gave me no issues, but appears to have a slightly lower viscosity than the Redline. I figured with nearly five thousand lbs of weight riding on this new transmission, a slightly thicker, ester based formula (Redline) probably wouldn't hurt anything.

I couldn't tell you which one shifts "better" (Synchromesh with the used transmission or Redline with the new transmission). The newer transmission feels ever so slightly "stiffer", as in slightly more effort to go into gear, but I'm not sure if this is a side effect of the Redline, or if it's the fact that my newer transmission is not fully broken in yet. It could also be the brass synchronizers vs. the carbon fiber synchronizers as well. Bottom line, so far, both work/worked extremely well. Most people would likely not notice a difference.

All in all, after installing everything, everything is quiet as a mouse and smooth as butter. Combined with my rebuilt front differential, the thing feels like a brand new vehicle.


After a considerable amount of research, it appears that the early model AR5's for the Colorado/Canyon featured standard (non-reinforced) gears, and all brass synchronizers. In the 2007+ H3 models, the AR5 features several Carbon Fiber Synchronizers as well as some Shot Peened gears for added strength to take on the additional weight of the H3. This means that the 2007+ models are in theory, much stronger than the 2006 and earlier models. With that in mind, it will be interesting to see how this "stock" transmission holds up over time to the weight of my H3 with 33" tires.

I couldn't find too many "Hummer H3 Manual Transmission" replacements available, and the very few I could find were rather expensive. There were a considerable amount of Colorado/Canyon manual transmissions for sale across the web (ebay, junkyards, etc.) and they were all significantly cheaper than the H3 versions. Shops that are willing/able to rebuild an AR5 are becoming more and more scarce as time goes on (couldn't find one in a 200 mile radius from central MS), so having a few more options available to choose from will hopefully make it easier for those who need a new transmission.

Regardless though, it is completely possible to swap in a Chevy Colorado/GMC Canyon 2.8/2.9L AR5 into your H3. Hopefully this gives a little bit more variety to those out there who own a 5-Speed H3 and are in need of a replacement.

If anyone has any questions, feel free to DM me!

 

Excellent info; thanks. Not that I have a manual, but still...