My 2009 F150 with the 6R80 transmission is downshifting hard from 4th to 3rd gear. All other shifts are fine. This only happens under load, climbing a hill, pulling a trailer, etc. It has 23,000 miles. The dealer reprogrammed it but this didn't help. Also, how do you know when to add trans. fluid? There's no dipstick.

 

Can't help you on the hard shift, but as far as tranny fluid, my understanding is that if you have no dip stick then your tranny fluid is good for 100,000 mi's. The reason I think that is yesterday I called to see how much a fluid change was and the service person wanted to know if I had a dip stick or not. I do so she said 30,000 for severe service, ie towing. No stick 100,000 regardless of the type of use.

 

If you go under the truck, there's a plug in the tranny to check the fluid.