https://www.chevrolet.com/performanc...ermatic-4l75-e

 

The H2 uses a 4l65 but the only difference over the Alphas 4l60e is the 5 pinion planetaries while the 4l60e is a 4 pinion. (The builder showed me in order to sell me the pinions, I ended up buying then) How much of an upgrade is it is unknown as no one online documented breaking them. The ones that are documented to break are aftermarket units (not oems) and on most aftermarket performance 4l60 builds you can source from reputable builders they usually leave out the pinion upgrade as oems are expensive or can be sourced used from a select nunber of transmissions.
Those new transmissions offered by chevy arent really a big upgrade. The parts offered in the 4l75e are already provided by any upgraded rebuild kit you get online. I built my trans with even more upgraded parts than offered in the chevy 4l75e, cost me less as its not a new GM unit, and it still failed early. A 4l60 can never be a 4l80 and the 4l75e coding is a marketing gemmick to give the impression its almost as good!
A 4l80e is also more superior than a 6l80e but the gear spacing on the 6L is a huge benefit.

 

When I was wanting to upgrade, I could find 2wd versions but no 4x4. I ended up having one built to exceed the specs in my original case. I used GM components with the exception of those known to be inferior to aftermarket (such as the pack, 1-2 accumulator etc). So far, really satisfied. There may be a 4x4 version available now but I haven’t recently tried to fin one.
Thanks

 

I think I came.........!!!!

 

Latest update. The tranny failed again (that's 3 failures in about 15000 miles). This time I didn't even bother taking it back to the trans shop that did the rebuild because it's obvious they are not capable of doing a trans that can handle this torque. We decided on "Monster Transmission" to build us one because they claim to build HP trans for high horsepower applications. They said they could build us one and they needed prepayment and it would take 4 weeks. Six weeks later we still had no tranny so we threatened to reverse the credit card and opened a dispute with the card company. Low and behold a trans appeared in about a week but it had the wrong bell housing and torque converter (they made a 500 HP tranny to fit the 5 cylinder engine). We sent it back to them and they again dragged their feet so we canceled the credit card payment completely. Now they claimed they could get us a tranny in a week but at this point we decided the bad experiences were just too much to overcome. We ordered a (very expensive) GM performance tranny that is supposed to handle 490 ft. lbs. of torque but it comes with a GM 3 year warrantee. They know it's going into a modded vehicle and they will stand behind it. Hopefully this one will solve all my problems.

 

is it the 4L75-E gm option ?

 

What did you do for the wiring harness?

 

Wrote a check.

 

Tranny problems continue. After another rebuild we've added an additional trans cooler running in series with the first one. Going to monitor trans temps which have been running about 230. I'm hoping we can keep it under 200.

 

Whats your cooling setup? Im surprised you are into such trans temps.
if it helps, im running a tru cool 40k trans cooler completely bypassing oem radiator. Its more than sufficient to keep my trans at 180* during normal driving with 37s and 4.10 gearing, was 170* before that with 35s. I only see temps spike to 230* when my 3200 stall converter is unlocked when I sustain 100 mph for a long time on the highway (this issue started after going from 35s to 37s due to my 4.10 gearing). I was going to get a second trans cooler but since my issue is caused by the converter running unlocked at higher highway speeds, I found that regearing would be better (got a partout H3 with front/rear 4.56 diffs with 75K miles for almost free)
Another thing, reprogram your trans to lock in 3rd, delay upshifts & downshift earlier. It dropped my trans temps in the city by 10*