QuestionI have a 1986 L7 with 159,000 miles in excellent shape. I have an unusual transmission problem which has us stumped here in Boise ID. For over a year on an off and on basis the transmission will shift in and out of 2nd and 3rd in an almost rythmic pulsing manner every second or so. This occurs after accelerating and then letting your foot off of the gas pedal--speed generally being 35 to 40 mph. Accelerate and the problem goes away until you let off the gas again. It will literally oscillate 1000 rpm or so causing the care to jerk. It will then either go to "limp home mode"--3rd, or you can stop the car, turn it off, and it will reset and be fine. This will occur often for a few weeks and then may go away for months. It has happened on the freeway ant 70 mph also. Does not seem to be heat related.
Neither my service guys, Hurless Brothers, or the AAMCO guys, or the dealer had a clue.
To add to this, last month the transmission went completely out and AAMCO rebuilt the transmission and I hoped that my problems would be history--but no, after a few days the same problem recurred. The AAMCO guy is a good friend and admits that it is most likely electrical, but he is stumped. The only other symptom I can add is that when you back up and shift from reverse to neutral to drive, if you are not completely stopped as you put it into drive, there will be a huge jerk as it engages with no slippage at all. This happens even if you are almost completely at a stop.
Hope that you might have an idea, or where I can go to ask.
Sincerely Dave Cutler
Answerit is most likely electrical. i do not know for sure if that transmission is computer controlled or vacuum controlled. either way, the control system should be checked. if it is electronically controlled, it could be the computer, if it is vacuum controlled, it could be poor vacuum to the transmission.
