* Please help! 4L60e shift problems after 5.3 swap in a 1994 Chevy C1500 (OBS) Shorti
11-14-2013, 04:31 PM
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* Please help! 4L60e shift problems after 5.3 swap in a 1994 Chevy C1500 (OBS) Shorti Hey guys hopefully someone can help me out on this issue I have. I recently swapped a 5.3 in my 1994 C1500 W/T which had a tired 4.3 in it. The motor turns on, is healthy but I am having trans issues. I moded the oem engine harness with emissions deleted and wired it up using lt1swap.com as well as having Brendan from that website remove the VATS. I am using my 1994 trans (because of funds) and he also deleted the PWM from the pcm because the 1994 trans does not have it. Before I found out he deleted the PWM, I changed the internal harness of the trans to that of a '96 and later because it has an extra pin in the plug for the PWM (I still have the original one) thinking the PCM could control the trans that way. All my gauges work including the speedo ( I have no tach from the factory though). I have checked the trans fluid level and it is where it should be at operating temp. Now here is the trans problem. When in OD or D it does not start off in 1st gear. Instead, it starts off in 2nd gear then when you think it should shift to 3rd, it shifts to 1st. It stays in first and does not shift until I slow down to a stop then I can take off again but its in 2nd gear. If I go to L2 or L1 its in 2nd gear all the time. Reverse works fine. I have the OBD 2 connector and hooked up the scanner and no codes even after I drove it locally for about an hour. But then again, since its a weekend driver, and for antitheft reasons, I disconnect the positive terminal and the fuse for the power on the harness. Please help !! By the way, I have posted this on LS1truck.com also
11-14-2013, 08:32 PM
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First, PWM is only related to how the TCC lockups up, generally in 4th gear.
It has no effect on the shifting of gears.
Those are crazy symptoms; even with the wiring to the shift solenoids mixed up I don't see it. Still, it sounds like an electrical or PCM problem.
Here is a link to the wiring diagram of a 4L60E:
http://www.msgpio.com/manuals/mshift/wiring.html
My post #15 in the following thread shows what shift solenoids and clutches are applied in the different gears.:
https://ls1tech.com/forums/automatic...-drive-od.html
Perhaps this will point you in the right direction.
It has no effect on the shifting of gears.
Those are crazy symptoms; even with the wiring to the shift solenoids mixed up I don't see it. Still, it sounds like an electrical or PCM problem.
Here is a link to the wiring diagram of a 4L60E:
http://www.msgpio.com/manuals/mshift/wiring.html
My post #15 in the following thread shows what shift solenoids and clutches are applied in the different gears.:
https://ls1tech.com/forums/automatic...-drive-od.html
Perhaps this will point you in the right direction.
