1991 Transmission Problem

[michjm]

My 1991 (145,000mi) is starting to slip/jerk at around 45mph, overdrive on. If I increase or decrease speed, this problem goes away. I dont experience this at any other speeds and it happens when the car is both warm and cold. All other shifting is fine.

In talking to a mechanic, he suggested driving it for a day or two with the overdrive off. If the problem goes away, it is the torque converter. If the problem continues, it is the transmission.

Does this sound like a good way to diagnose? Would the conclusion be correct?

Only 145K doesnt seem right for an LS400 driveline, are there any other suggestions as to what the problem might be? Anyone experience something similar?

[nc211]

Fluid....have you drained and filled it? You've got to stay on top of the tranny fluid at your mileage. You might not believe this "i didn't at first" but the fluid makes all the difference in the world on these cars! You have three options. One is to go to the dealership and have them powerflush it to get everything out. $100 bucks or so. Two is to search on here about tranny fluids and learn how to do it your self "www.lexls.com" is a great site! Three, this is the simplest thing to do on the car. Do a drain and fill only. Under the car, look for the tranny pan...you should see a lonley bolt. It will drain 2 quarts. Tranny holds more, but drain and fill will only take out two by design. Drain the 2 quarts, put plug back in, and fill back with TOYOTA TOYOTA TOYOTA FLUID. You can buy the fluid in 1 quart bottles at the dealership for a few bucks. Do this, drive it for a week and then do it again...and again...and again, until the old fluid that is draining out of the pan is the same "BRIGHT RED" color as the new fluid. By doing the drain and fill method, you are not putting stress on the seals "power flush does this", you are also measuring to make sure you're not over filling / under filling. 2 quarts out....2 quarts in. I bet you will be amazed at what your tranny fluid looks like when you drain it. Mine was BLACK at 25k miles of usage. Now, after three drain and fills...she's bright red and smooooooth as a baby's butt.

My 1991 (145,000mi) is starting to slip/jerk at around 45mph, overdrive on.  If I increase or decrease speed, this problem goes away.  I dont experience this at any other speeds and it happens when the car is both warm and cold.  All other shifting is fine.

In talking to a mechanic, he suggested driving it for a day or two with the overdrive off.  If the problem goes away, it is the torque converter.  If the problem continues, it is the transmission. 

Does this sound like a good way to diagnose?  Would the conclusion be correct?

Only 145K doesnt seem right for an LS400 driveline, are there any other suggestions as to what the problem might be?  Anyone experience something similar?

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[VBdenny]

NC, are you saying that when you drain the tranny pan via the drain bolt that exactly 2 quarts comes out each time? I do like your idea since most places yuou would take the car to have this done simply do the same thing you have been doing but only once. Where is the cheapest place to get the Toyoto transmission fluid?

[nc211]

On the 95-97 models "and maybe 98-00" it is exactly 2 quarts that comes out. I double checked the manual and called the dealership to make sure "I didn't want to screw up the tranny..God that would suck". It is 2 quarts exactly "supposed to be anyway." If you're low on fluid, then it won't be the 2 quarts. But once you refill, then you're back to even. I actually buy mine at the Lexus dealership for some outrageous price of $8 a quart. But, I think you can get it at the toyota dealership for a lot cheaper. It actually says "Toyota" on the bottle and not "Lexus", so I would have to believe you can get it at a Toyota dealer for cheaper.

You should also buy a new O-ring for the bolt too, what's an extra buck or two for the security of no leaks?