 |
PROBLEM
I found the problem with the 4L80E transmission staying in 2nd gear only in my 1997 GM pickup.
ANSWER
Removed trans. oil pan.As the shift solenoids require a ground signal to complete the circuit via the trans.ECM, I checked for a power supply (12V) to both solenoids and found none.The 10amp fuse for the trans. was OK.I then checked for continuity between the 12V supply wire (pink) and the end that plugs into solenoid with my meter...no conninuity. I then realized there must be an open in the circuit,and most likely at the firewall junction point.I was not going to spend all day disassembling that component.
Therefor,I cut the old dead (pink)12V supply wire and ran a new wire from the "E" pin of the 20 pin harness that plugs into the left side rear of trans. and routed it through the GM trans.split loom harness (very difficult)up and through the firewall to the factory 10 amp trans. fuse wire which I cut 1.5" away from the fuse box and soldered both ends.
The transmission now gets its 12volt power supply as it did before when the key is switched to the run position and the trans.ECM provides the ground signal for shifting each solenoid. Trans.now shifts perfectly once again.
Commentary
As a Lisenced mechanic I am once again disappointed with the quality of electrical workmanship in this vehicle.This truck belongs to my Dad,he bought it new and has only 35,000 miles on it in 10 years and always looks after it. |
RV and bus conversion info since 1996.
email Den
reply to message
search forums