Reward! Unknown Territory - Manual transfer case causing havoc
Hummer H2 Running Duramax LBZ / Allison 6spd stock. In an attempt to retain the H2's AWD functionality after conversion, I mounted a built AMG NP 242HD behind the Allison. The 242 is 5 position manual transfer case. 2WD, 4PT, 4FT, N, 4LO. The transfer case runs perfect as it should in position 1 - 2H.
Problem:
in position 3 - 4FT. (4FT is open transfer case going to open front and rear differential and is intended to run on dry pavement) very hard shifts in each gear and eventfully throws a code in efilive P0776 - PC solenoid B stuck off and p2723 in Tech2. When DTC is lit what ever gear its in will not change. I have to reset code to get back to gear 1. With each hard shift it seems to rev rpms a bit prior to each shift. If I stay off the gas or going down hill I can create a soft shift but under power it's exceptionally hard.
The ECM and TCM do not know electronically the difference between 2H and 4FT. I have a jumper on the gear indicator switch and can force signal either 2wd or 4wd and the results are the same in any mode. 2WD works great 4FT hard shifts.
I recorded a log in 4FT (attached) Selected 50+ PID, I thought were important but this is not my wheelhouse. I can also record a log on the same course in 2WD for comparison. For this log file, the ECM thinks it has 30" tires when in actuality it has 37's. I will make calibration and record again.
Driving the front wheels via the 242 transfer case is causing the issue- extra torque, windup in the front end, gear ratio problems, ??
At one point, after running in 4FT, I cleared the tap shifts and did a rapid relearn using Tech2. After, I was initially getting hard shifts in low gear in 2wd. (maybe normal with relearn in any situation)
$100 reward for solving and fixing the problem. But fixing can't hurt my other drive modes. 2WD, 4PT, 4LO
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