Upshift Light On C4
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I know this thread is old, but just in case somebody finds it with no solution...
The 700r4 has a switch inside that tells the ECM that it is in OD. Apparently that connection is broken.
The ECM does a RPM vs. MPH calculation to determine what gear the transmission is in. On my car it will turn on the shift light at 42 MPH (3.07 rear gear) if I'm in D.
The 700r4 has a switch inside that tells the ECM that it is in OD. Apparently that connection is broken.
The ECM does a RPM vs. MPH calculation to determine what gear the transmission is in. On my car it will turn on the shift light at 42 MPH (3.07 rear gear) if I'm in D.
Pro
Joined: Jun 2007
Posts: 626
Likes: 2
From: Coquitlam British Columbia
I had the same problem on my 1990 Vert when I went from 2.73 gears to 3.54's. I changed the drive and driven gears and also bought a used VSS from a forum member. The old VSS was for 34-39 tooth driven gears and the VSS can handle 40-45 driven gear. Note; these #'s are stamped on the VSS in case you are in need of one. The 3.07 VSS 40-45 T will handle a gear swap up to 3.73's. The lite does come on now and when I did it a few years back and asked for help the common solution was to reprogram....pull lite bulb or live with it. My TC comes on when it should (per Autoxray diagnostic while driving) so I live with it. I either slow down or speed up to kick lite off. It takes a few minutes at driving a steady speed say 55mph and up for it to kick in. One of these days I may pull the bulb but have gotten used to it.
Bill
Bill
