91 previa transmission problem - Toyota Nation Forum : Toyota Car and Truck Forums

grego · 10-13-2004, 09:57 PM

I hae a 91 Previa with uto and overdrive. Recently the transmission slips, or pops out of overdrive at soft throttle mostly on the highway, cruising along. Seems to happen when little load is on the engine/tranny.
Is there a solenoid or other electrical gremlin possibly, or should I begin looking for replacement? It slips (engine revs, car slows) for maybe 1 to 2 seconds, then back in and good for a while longer. Feels like a manual tranny if you depress clutch and immediately let it back out. It happens maybe once every fifty miles or so.
The tranny had full service (no power flush upon recommendation of tranny shop), about 2k miles ago. This issue began about 1k miles ago.
A related question, should the overdrive be turned off when ot in highway use?
Any help? Thanks! Greg

es250nut · 10-14-2004, 09:12 PM

I've seen this exact same question before....

Someone on this Previa Group is having the exact same problem in an 92 LE. Go and check the last weeks worth of posts. They have several thoughts on what is causing this particular problem.

grego · 10-14-2004, 10:09 PM

Thanks for the tip on the Previa transmission discussion. Those symptoms are exactly the same as mine. I will keep an eye on those guys, while I keep researching, and maybe we can all get a solution. Thanks! greg

94previa · 10-15-2004, 08:46 AM

I had the same problem last spring. I couldn't decide if it was the trans or a fuel problem.

I took it to a transmission shop and the guy told me it wasn't the trans because it was shifting well, just that it was shifting when it shouldn't.

I bought a used throttle position sensor and it fixed it perfectly.
I've read that this is a common flaw with the previa, that the harness is actually what causes the bug.

grego · 10-16-2004, 09:01 PM

Thanks for the TPS info. Did you replace the TPS alone? Or TPS and harness? Was it a big deal? Where did you buy the parts? Online...any recommendations?
Thanks for the help! Greg

previa92le · 10-19-2004, 08:48 AM

Check the TPS harness for signs of wear and tear first. I understand there's an area that wears through resulting in open/short circuit.

Wm
92LE, 194K miles

amjalara · 05-20-2011, 02:42 PM

Mine was slipping. was the cable the goes from throttle to transmission. It gets stuck, broken in time. this cable controls fluid pressure inside transmission. I knew it was stuck but thought this was just a kick down cable. wrong, transmission shop diagnosed and replaced cable. worked find after that.