94GS300

Alright, I have seen quite a few posts for a number of different cars in here that seem to have the same problem I have, or at least I think they do. I have a 94 GS300. The problem is when the car is first started when it is cold outside (below 30F). I let the engine warm up for about 20-30 seconds and then put it into Drive and drive very slowly to take it easy on it. Basically I have the throttle at maybe 5-10% at the most and it will shift to 2nd and everything is fine. When I get to the first street where some slight acceleration is needed, the engine rpm's climb sky high in 1st gear, but the car barely moves. It does this for about 5-10 seconds before it shifts to 2nd and then the problem never comes back. This is so bad that it is very dangerous because people almost rear-end you.

In order for the rpm's to climb and the vehicle not go as fast as it should in 1st gear (correct speed ratio), one of two things must be happening:

1) The transmission is slipping one of the clutches
2) The torque converter does not have enough fluid in it

A lot of people are claiming that the computer is doing this to warm up the fluid faster, but I find that hard to believe. I need to get a schematic of the transmission controls, but the only way the transmission controller would be able to change the speed ratio (output speed/input speed) would be to back off line pressure which would make a clutch slip or cut off fluid to the torque converter. The controller would do neither of these things because it would not reduce line pressure and risk slipping a clutch in 1st gear and it would not cut off fluid to the torque converter because the torque converter is what causes the transmission fluid to warm up.

Any Lexus technicians or anyone else have a good explanation for what is happening? I personally think I am slipping a clutch when the fluid is very cold because either a valve is not opening all the way, a solenoid is not producing enough pressure, or I some debris in an orifice (not likely since the fluid pressure would blow it out). If this was the case though, then all these other people complaining about this would have slipping clutches and we would here more about these incidents.

I have done all the obvious things: fluid level is correct with fairly new fluid and I cleaned the metal filter screen.

Anyone want to take a stab at this?

mooretorque

94GS, I agree, you have tranny problems.

It is true that (at least on my wife's RX but I've noticed no such behavior with my GS) the ECU will hold 3rd gear until fluid temp hits 186 F, so I hold the speed down for the sake of the motor. But it accelerates normally regardless. You describe significant slipping and that is NOT occuring in the RX nor is it normal.

I agree with your analysis. You might want to go post over on the Maintainence forum (DevilDog is a Lex tech), but it sounds like you've got a visit to the transmission doctor in your future............

(And after I posted this, I went over to the Maint. forum and saw that you already had.........)

rominl

iTrader: (4)

yeah sounds like a tranny problem. it is never that cold here in cali, but it shouldn't do that