Old 1991 Corolla Wagon Problems - Pre-1997 Toyota Corolla and Geo Prizm

I got this 1991 Corolla DX wagon with 3 speed autotran one year ago and used lightly for weekly grocery etc. The car had 136000 miles and I added 4000. It looks like that the previous owner had regular maintenance and I carried this on. There have been a few problems since I got the car: the biggest was that it stalled in front of traffic lights in wet weather, shortly after running and came totally normal after running for a while, especially on high way. I solved this by change the distributor and roter after some online research.

There are still some problems: 1. when I wait in front of traffic light or idle the car in D gear, there are some vibrations. The vibrations are not constant and they come and go. It gets worse and better sometimes. Especially when I drive locally, where lots of stops and gos, the change-oil light will be on sometimes, shortly after oil changes. The light goes off when the car starts to move. 2. shifting the gears to D normally cause the car jerk forward. If I do it slowly, it's less obvious. But shifting to other gears is fine. I therefore always shift slowly with care. 3. When the car accelerates from <~20 mph to >~20mph, the car jerks: the engine first rotate fast but the car accelerate slowly, then feels like the torque is caught up by the tran, engine to a lower speed and the car accelerates normally. I checked the ATF and it looked pink and smell OK ( though I am not sure what's really OK). I took to a mechanist and he said it's normal for this old 3 speed trans and I'd better let it be.

Please give some suggestion, thanks!

The vibration problem could be motor mounts. Is the engine running rough when it vibrates? As to the other problems, my guess is that you need a new transmission, but that's just a guess.

I don't know that the differential is the part of your transmission that is bad (because I'm not a transmission expert). However, since I've been filling the differentials on my '89 and '90 Corollas, I'll mention the following:

The differential in the A131L 3 speed automatic transmission has its own ATF reservoir that is not connected to the reservoir of the main transmission. To check and fill it you must remove a bolt on face of the transmission that faces the back of the car and is behind the axels. The bolt is in a small depression. If you put the car on jackstands and remove the drivers side front tire, you can sit in the wheel well and see this bolt. Using a box end wrench with a small offset or a slanted box end you can reach under the car and undo the bolt. The bolts on my 2 Corollas have 24mm heads. I have out-of-car transmissions where the bolts have 14mm heads. The differential should be filled till fluid begans to come out the fill hole. Hence if you stick your finger in the hole, you should get ATF on it. On many cars, people neglect the differential so much that's it's nearly dry. The service manual says its capacity is 1.5 quarts. To fill it you can use an inexpensive pump (available at auto parts stores) and tubing to pump the fluid in. There isn't room to pour fluid into it from the container. I suppose you could also try using a funnel and some tubing.

I don't know enough about transmissions to say what the symptoms of a bad differential would be, but I suspect they wouldn't be specific to changing gears. I see nothing in the mechanics of the differential that uses hydraulics, so I don't think filling the differntial would fix any problem, but it might prevent a big problem.

increasing the idle speed should keep the oil pressure light from coming on and it might reduce the vibration at idle speed.

Thanks a lot for the detail explanation!

The vibration problem could be motor mounts. Is the engine running rough when it vibrates? As to the other problems, my guess is that you need a new transmission, but that's just a guess.

I don't know that the differential is the part of your transmission that is bad (because I'm not a transmission expert). However, since I've been filling the differentials on my '89 and '90 Corollas, I'll mention the following:
The differential in the A131L 3 speed automatic transmission has its own ATF reservoir that is not connected to the reservoir of the main transmission. To check and fill it you must remove a bolt on face of the transmission that faces the back of the car and is behind the axels. The bolt is in a small depression. If you put the car on jackstands and remove the drivers side front tire, you can sit in the wheel well and see this bolt. Using a box end wrench with a small offset or a slanted box end you can reach under the car and undo the bolt. The bolts on my 2 Corollas have 24mm heads. I have out-of-car transmissions where the bolts have 14mm heads. The differential should be filled till fluid begans to come out the fill hole. Hence if you stick your finger in the hole, you should get ATF on it. On many cars, people neglect the differential so much that's it's nearly dry. The service manual says its capacity is 1.5 quarts. To fill it you can use an inexpensive pump (available at auto parts stores) and tubing to pump the fluid in. There isn't room to pour fluid into it from the container. I suppose you could also try using a funnel and some tubing.
I don't know enough about transmissions to say what the symptoms of a bad differential would be, but I suspect they wouldn't be specific to changing gears. I see nothing in the mechanics of the differential that uses hydraulics, so I don't think filling the differntial would fix any problem, but it might prevent a big problem.

This is something easy for me to try! Thanks!

increasing the idle speed should keep the oil pressure light from coming on and it might reduce the vibration at idle speed.