I have a '96 E250 cargo van with 88k miles that's converted for a wheelchair lift. It has the 351 Windsor with towing package (it has never towed anything). It has been revving up at about 25 MPH and then slamming into the next gear up. It usually does it when I'm driving around 25 MPH in stop and go freeway construction or around town. Not so much when I'm accelerating through 25 on a freeway ramp, but it does seem to rev high before upshifting. It only seems to do it between the same two gears. I just got the transmission cooler and lines replaced, new filter, and the fluid flushed and filled, but it didn't help. Does anyone have any thoughts?

Best Regards, -Jim

 

Do you know which model of transmission you have? For an AOD it sounds like a broken 1-2 accumulator spring. Where's our transmission guru?

 

That truck is going to have an E4OD in it which is computer controlled so step #1 is to pull the codes.

 

It's a 4 speed automatic with overdrive, but idk the model. I'll take it back to the dealer or to Autozone to pull the codes. I thought they would have done that when they were working on it because I had a lot of work done, but maybe not. Thanks for the ideas