'96 Camry Station Wagon Transmission Issue

[ngottlieb]

I have a 1996 Camry station wagon with an automatic transmission.

About 6 months ago, I was driving on the highway with O/D on and the car started doing what felt like rapidly downshifting and upshifting back. The RPMs kept jumping up and down and the car started jolting. I slowed down, it continued essentially until I stopped the car. I got it checked out and the mechanics couldn't find anything wrong with it. So I kept driving it and never had the problem again until yesterday when I was driving around 45-50mph w/ O/D off and it started happening again. I thought maybe it was a computer problem and that restarting the car would fix it (since last time, the car worked as soon as it got to the mechanic). That didn't help -- it still had the problem. But when I tried again about 4 hours later, the car was totally fine.

So my questions are, what are the possible problems that would only happen twice in 6 months? A sensor issue, a torque converter issue? What's probably wrong and how much will it probably cost to fix / is it worth fixing?

Thanks.

[ASG14]

Any Check Engine Light (CEL) or any lights on the dash that should not be?

[ngottlieb]

Nope, nothing.

[ghettosled]

just curious, do you normally drive 50mph with the overdrive off?

[toyomoho]

With the O/D ON or OFF did the transmission do the same thing, engine RPM jumping up and down? Did it feel like the trans was shifting gears or just the engine RPM was changing?

Might be the torque converter is going in and out of lockup.

Lockup is controlled by the computer through solenoid valve 3 (also called SL). The computer used inputs from the coolant temp, speed and throttle position sensor, neutral switch, cruise control, stoplight and driving pattern switch.

Is the overdrive light blinking when driving and O/D turned on?

Might be the SL solenoid is sticking, wiring issue, one of the sensors or switches is having a problem. How is the transmission fluid, clean or dirty. Is it up to the fill line?

The shop finding nothing wrong just means the problem comes and goes, plus no trouble codes were stored.

If the fluid is dirty suggest changing it all as a first low cost step. The SL valve can be accessed by removing the trans fluid pan (no need to take the trans out).

[ngottlieb]

Originally Posted by toyomoho

With the O/D ON or OFF did the transmission do the same thing, engine RPM jumping up and down? Did it feel like the trans was shifting gears or just the engine RPM was changing?

Felt like it was shifting gears, but I can't be totally sure.

Is the overdrive light blinking when driving and O/D turned on?

There is no O/D light in my car.

Might be the SL solenoid is sticking, wiring issue, one of the sensors or switches is having a problem. How is the transmission fluid, clean or dirty. Is it up to the fill line?

Yup, fluid level is fine, and pretty clean.

I usually go 50 with o/d off, usually turn it on around 60.