A few months back I replaced my tranny filter and fluid and also drained the torque converter. I filled the system back up with Valvoline For Higher Mileage Transmissions fluid. Seems like the shifting is actually harder now and I get the "getting rear ended" feel when I move from a stop. Could it be the Valvoline fluid? Should I re-drain the system and buy some fluid from the dealer?

Thanks

1999 F-150 4x4 5.4 V8

 

I've never been a fan of anything 'for high mileage" vehicles because they typically have seal conditioneers that you may or may not need, in addition to other additives.

If the only thing that is differnet is the fluid, I'd try changing it.

 

I used to run the high mileage Valvoline ATF in my old lady's oldsmobile. Man did it love it. It shifted as smoother than when it was new! I would pobably agree though, if your tranny is not agreeing with it change it out. I used the Valvoline Mercon V in my 01 the last time and it is doing great.

 

I replaced my filter and fluid last fall and went with the same fluid.
The thing is it needs to be mercon 5. On 96 and newer Ford recommends mercon 5. I had 84K on mine and had some torque converter shudder and was kinda concerned. I changed the filter and fluid and put in an additive called Shutter Guard and things are running great. I installed a superchips 1715 tunes and things got even better. The Shutter Guard product was recommended by the tranny shop I use and they have been in buisness for many years and know there stuff. In most cases if the tranny shop knows what's going on and keeps up with all the problems with certain transmissions they will correct and improve. They have to deal with the problems when they come threw the door and keep there customers happy and coming back to them for service. If they can't they won't be there long. Good luck!!!!!
F96XLT