blake96

So I recently received a sc400 and there is a delay in shifting from 1st to second. Also it jumps into first from neutral...shifts smoother after that. No transmission codes come up. Also, one day I floored it on a highway and at 90 mph the car kept downshifting and up-shifting. Could flushing the black tranny fluid solve this problem?

Towersigma

Black transmission fluid??? That's nuts. I will tell you this... I had an experience with a 92 w250 (I know totally different) that had a similar issue. I decided (against my co-worker's advice) to drain and refill the transmission fluid and change the filter. Well less then a week later the transmission did what he said it would. It began to slip to the point where I could no longer drive it. This is because the dirt and grime in the old transmission was the only thing keeping everything from slipping. This is what my buddy told me but I didn't listen. If you decide to change out that fluid be prepared to drop that transmission and either rebuild it or replace it. Or you can just deal with it and make sure it's always toped off until it gives out on you. Regardless it sounds like thE transmission has been neglected. Sorry dude.

Bankswood

Don't agree. I've heard not to "flush" the system because it could break grime and dirt free and cause problems. If your fluid is black it needs to be changed. It has lost its ability to lubricate. Draining and replacing is only going to get 3.5 quarts out. I would do that and see if the additional new fluid helps. After drivng for awhile I would drain again and add more new fluid. Repeat on occasion and eventually you will have replaced all the bad fluid. Your fluid should always be pinky red.

PseudoK

throw in some automatic transmission conditioner into the new fluid.


It has worked for me ONLY in an american car, the transmission overheated and shifted hard and it fixed all of that.