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Discussion Starter · #1 ·
im posting this around to the forums i post on in hopes that someone who knows auto trannies will have and advice for me.. this is beyond my ability to diagnose, i have no idea how the hell autos work haha


i was just given a pretty damn nice 89 240sx auto for free, the only problem is that the tranny is stuck in drive... the stick moves and locks how it should and its linkage is fine and connected and adjusted correctly. i figured it was just a nasty clogged old valve body causing it so i went out and got a new filter and some fluid and took it apart to clean it..

well, i got it apart and the filter looked really fresh.. and for some reason there was a drill bit stuck to the magnet in the pan, so im obviously not the first one to have gotten in there. even though it looked clean i still took apart and cleaned the valve body and the solenoids pretty well... though i didnt take any of the VB's moving parts out for inspection since i wouldnt know what to look for, i did give the whole thing a very liberal dousing in brake cleaner. then i put it all back together and pow! i had reverse! park was park without drive fighting the park lockout, neutral was actually neutral, and best of all- reverse moved the car backwards, and drive worked like it always does.

this was all well and dandy sitting in my garage moving inches while testing it, but then i took it for a real drive and it was slipping badly, turned out the fluid was a couple quarts low so i put more in to the correct level, and that cured the slipping, but lo and behold it was stuck in permanant drive again.

i was out of ideas so i just started daily driving the car without reverse to see if any other gremlins popped up, and so far none have and its actually regained a few functions.. like the trip odomoter haha..

THEN, today the tranny started getting stuck in different gears as i was driving.. id get it up into third and when i came to a stop it would just stay there and id have to leave the line at snail speed in the wrong gear.. i soon discovered that if i shut the car off then started it again it would shift ok for 20 seconds or so, but then it would start getting stuck in a gear again. i figured it was something electrical since restarting cured it, so i borrowed a friend thats all into 240sx's tranny computer and that cured the sticking gears, so now it shifts fine AND is able to get into 4th gear (overdrive).. it wouldnt go above third on the computer that came with the car..

but theres a catch. 4th gear will only engage while the engine is under a little bit of load.. so say im cruising along at 60 mph. the car will shift normally 1-4 to get to 60, then when i let off to maintain speed it shifts back down to third. if i give it a little gas it will go back into 4th every time, but as soon as you let off the throttle it drops back to third.

its a long story i know, but im hoping an auto guru will be able to tell me that a spring is sticking or something in the valve body is out of adjustmentand all i have to do to fix everything is move it back into place haha.. the tranny shifts fine and runs fine other than the inability to hold overdrive and the fact that every position on the gear selector is drive.

any ideas?
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