Syntetic or high performance fluid

[TampaDriver]

just changed transy fluid and put in high performance oil but now it does not shift smoothly. I shifted better before changing oil. What do you think it is?

[Daunttless]

Maybe you did it wrong?

[redrocket]

wrong weight oil

[TampaDriver]

I put 80 W - 90 while it requires 75 W - 90 ... I don't think that could cause that much of a dfference...

[Aries]

You may have put in too much fluid.This would cause a little bit of slipping as it shifts.

I did this not too long ago as well.Just let it run for about 10 minutes, and check the level with the dipstick.If it is higher than the top of the HOT marker then drain a little out and repeat.Ideally you want it in the top 3/4 of the HOT mark after idling.This way when you really get on it, the overflow valve on the transmission isn't triggered by the rising level of the fluid.