Car has 180k been rigorously dealer maintained by prev owner. Trans fluid has been in there for a little while but the level is good and color still clean reddish (better than many other cars I've maintained).

Girlfriend had been driving this car for about 8 months, daily about 5 miles each way to work and back. I recently took the car out running errands...drove it for a couple hours in 103 degree Texas heat. I noticed the longer I used the car the trans was slipping the 1 - 2 shift. Felt like a manual trans letting the clutch out too slowly...about 2 full seconds for the rpm to drop into the next ratio. Once in the gear it felt good, didn't slip any more. The other gears were a bit softer but nothing so noticable.

We took it to a friend's and it sat for 8 hours. Drove home about 20 miles and the 1 2 shift was getting pretty soft again as we arrived...although not as bad. Outside temp was in the 80s now.

What's next here. I feel the dealer will try to sell me a trans. In the girlfriend normal commute I don't think it ever gets hot enough to do this. Can I ignore it? Should I flush the trans? Maybe a sticking valve in the valve body I can have that cleaned out ( without removing the whole trans).

Let me know if anyone has some suggestions. I can fix most anything myself with proper direction.

 

A drain & fill would be the first inexpensive solution to try, considering the millage & possibly never done, should certainly help.

 

Dealer has flushed about 3 times already in it's life...fluid is aging a bit but only affecting 1 gear.

 

Has the trans filter and it's gasket ever been changed?

 

Unknown for sure. I pulled the service history from the lexus owner's website. It shows the transmission fluid has been changed a couple of times. The previous owners had every single issue (down to light bulbs and adding air to the tires) done at the dealer, so it seems that if the dealer recommended ANY service to these people, they bought it. I mean they had fuel injection services done every 15k, etc etc. Probably overkill. So I'm not sure what the dealer "usually" does when they service these cars, but the fluid color and smell are very good.

I'm shying away from a line pressure issue (thus a filter issue) since the other gears do not seem affected. I'm concerned that there may be some fluid / pressure loss in the circuit(s) necessary to apply 2nd gear. I'm not an expert but I do have a general idea of how automatics work. I assume at higher temperatures the fluid thins out and may not seal as well? The part I don't fully understand - is there a way to test if you are dealing with a solenoid / valve body issue vs an actual clutch pack that is almost gone? Basically I'm hoping not to have to drop the whole trans out, if I can get away with having the valve body gone through or replacing a couple solenoids. Are there better fluids for this transmission that deal with higher heat better?

Thanks

 

AFAIK if you can access Techstream you may have it tested like this luckily.


I am also leaning towards a internal seal causing pressure low when getting hot.

 

If it were me - I would do a simple drain and fill and include a bottle of Lubeguard Platinum with the refill. See if that helps.

 

Update folks...

Trans pan dropped, filter replaced. Ran 12 qts of new Toyota iv fluid through it by drain and fill, drive around the block, drain and fill, drive around the block - you get it...

The 1-2 shift got worse, and then 2 -3 started to flare. Guess the new trans fluid had less "grit" than the old stuff. So in the mean time I received my VCI cable and software. I loaded up techstream and reset the ECT memory. Following the instructions on another post, I let the trans re-learn.

At first it was shifting very firmly, then it eased up as i drove to what i consider "normal" for most automatics i've been in. You feel a very slight change as the automatic goes to the next gear. This didn't last however...
Interestingly, as the computer seemed to learn the shifting - it simply went back to the way it was shifting before I changed the fluid. It almost seems like the ECU is doing this on purpose, or it is having difficulty detecting how long it is taking the shift to complete...

I don't have another car like this to compare it to...my ES350 shifts very quickly but thats a different trans....