i have a 91 nissan d21 pickup 4cylinder. i had the tranny rebuilt and only have 4000 miles on it.after shift problem, took it back to the shop and everything checked ok. however, after replacing the battery and alternator, it quit shifting to the final gear. pulling my hair out because it all ran me 2500, if anyone can think of a possible cause PLEASE let me know. much appreciated.
Did anyone scan the computer system for any trouble codes?
If a transmission code is present, it can lead you to the problem area.
There is a service bulletin on this condition. It is listed below.
TECHNICAL BULLETIN # 270
No 4th, Slips in 4th, Falls out of 4th, Low 4th apply pressure
DATE: JAN 95
Slips in fourth
Falls out of fourth
Low fourth apply pressure
These symptoms can be caused by a crack in the lock-up control valve end plug.
The RL4R01A uses fourth gear apply pressure to signal the lock-up control valve. With the fourth speed cut valve in the rested position, fourth gear apply pressure is blocked from reaching the lock-up control valve.
When governor pressure shifts the fourth speed cut valve, fourth gear apply pressure is directed between the end plug and the lock-up control valve moving the valve into the lock-up position
If there is a crack in the lock-up control valve end plug, fourth gear apply pressure can leak past the plug and out of the retaining pin hole. Since fourth gear apply pressure is fed through a .045"-.055" orifice, even a small leak can lower fourth apply pressure.
To fix this problem you can simply modify an end plug from a 4T60/440-T4 converter clutch regulator or the 4-3 MTV bore (GM part number 8649434). It is necessary to widen a section of the end plug groove to approximately .120"-.125" with a small file in order to allow room for the pin.
CAUTION The rounded side of the 4T60/440-T4 plug must face the outside of the valve body. The flat side must face the lock-up control valve.
Hope this information helps you out. Let us know how you make out.