I recently finished a transplant of a 94 3500 2 wd 454 and 4l80-E into a 90 2500 that had a 4.3 and 400 Trans. all the components were swapped harness, comp, sensors ect .
My problem is the Trans didn?t work. 2nd gear only, the Trans was sitting on my garage floor empty for about 8 mo while the motor was rebuilt When i dropped the pan to change the filter and gasket there was some water in the pan not even enough to cover the whole pan bottom.
i found too the original harness was leaking through the case connector and some of the connector ends were broken so in went the new gm harness now i had to swap the out side plug over sooo--- the comp set the check engine light codes 56,81,82 and 83 i think my first guess was no power checked all the pin outs again plug it in disconnected and re-connect the battery great no codes , and still only 2nd gear
OK maybe the problem is in the valve body ,maybe water ,from sitting went through valve body while apart. why not install shift kit sooo..... I installed a trans go re-programing kit new plate gaskets ect. by the book! and i did find what i thought were stuck valves when changing some springs out. filter/ screen was clean
re-assemble still only second gear
other notes snap on scanner wont communicate with comp. aftermarket chip z-industries chip for a 1991 454 ss 1500 race auto engine runs fine, i can get trouble codes from idiot light i am questioning ALDL harness its the 90 Chevy and the serial data port is port (E) im showing on the 94 a port (M) for the data port
Any Help will be appreciated