95 Suburban trans
SgtBone64
05-25-2004, 09:30 AM
When at 55 mph, it drops to 30 mph and the rpm's go up. Sometimes the vehicle will go no faster than 30 mph and the rpms are up.Had it at well known trans shop and they were unable to find the problem. Computer is OK according to them. Any help would be greatly appreciated.
RexNfx400
05-26-2004, 01:32 AM
The big tranny or the small one? Do you know? It could be helpful...:)
SgtBone64
05-26-2004, 03:41 PM
Its the big one
RexNfx400
05-26-2004, 07:00 PM
4L80E
Possible the shift solenoids are leaking fluid. They won't set codes because its a hydralic problem not an electrical problem. Can't say for sure as I'm not monitoring the data in the PCM. The input and output speed sensors can cause this also. I would bet on the shift solenoids though. Typical for shift solenoid "B" to leak, then lets fluid into the 1-2 shift valve circuit. This makes the tranny downshift.
Hope this helps
Possible the shift solenoids are leaking fluid. They won't set codes because its a hydralic problem not an electrical problem. Can't say for sure as I'm not monitoring the data in the PCM. The input and output speed sensors can cause this also. I would bet on the shift solenoids though. Typical for shift solenoid "B" to leak, then lets fluid into the 1-2 shift valve circuit. This makes the tranny downshift.
Hope this helps
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