I have a 99 GS 400 that I purchased in Jan. '03. I brought the car into the dealer in April because I was having very seldom, but, light slippage between gears ( the car seemed like it should be in third when it was still in second, no the car wasn't cold..)....The Lexus tech said that the fluid was very dark in color, yet did not have any type of burning smell. He changed the fluid and I haven't had any transmission slippage since.

I brought the car in again, in May, for an oil change and asked the tech to look at the tranny fluid again. He said that it was still dark, perhaps a bit lighter. Again he changed the tranny fluid.

I realize that only a small amount of fluid gets changed during a normal service, so I am wondering if I should get the tranny flushed with new Toyota Type 4 fluid or leave it alone? The car has 50k miles on it and is four years old...Warranty on tranny is 6 yr/ 70k...I want to protect my investment and keep this car well past 70k miles..I can't push the dealer, yet, to do anything (replace the tranny etc.) b/c there aren't currently any performance issues. Do I flush the tranny or not...I keep hearing that it could be detrimental to the tranny and that it could weaken up a worn part etc. Well if that's the case than I want what ever is to go wrong to go wrong sooner rather than later..

Anybody have any suggestions or experience with this?
Thanks,
Scott

 

I would take it to the dealer, explain your concern, and ask them to diagnos the problem. If nothing is apparently wrong with the system, that will be communicated on the invoice (in writing obviously) so if anything should go wrong down the road, you're covered.

BUT, if it were me, I'd also get it changed again, especially since you know you're going to be keeping this car for a while and beyond the warranty period. BUT, I have a higher stall TC, and a aux cooler, and I push my car form time to time, so its really just added insurance.

Changing the fluid again certainly won't hurt, and you'll gain some peace of mind which is priceless.

Its seems to me, that OEM trannies rarely fail unless you totally abuse them.

 

I recommend a complete flush with the trans flush machine. This machine is hooking up to the cooler lines by the bottom of the radiator. This type of machine will completely flush/exhance trans fluid, it will take about 14 qts of type-t fluid. If you're worry about wash out the weak part or worn part and the transmission fail, heck then it still under the warranty. But I don't think this will happen.