Hello, I'm concerned the transmission in my 1991 F350 seems to be in a bad mood this week. It is an E4OD with a 7.3 IDI diesel non turbo.

Ever since I have owned the truck, it has always wanted to buck in reverse. If I let the truck shift into reverse (which it never does instantaneously) and then slowly give it some fuel, it seems to do better.

Due to both fuel sending units not working, the truck ran out of diesel on one tank. I ended up deciding to change the fuel filter while I was bleeding it since I had some fuel issues last fall and I had been changing the filter element every 2000 miles. At the time, I was towing my heavy trailer and an antique tractor... about 2500 lbs, in addition to the service body and tools on the rig itself.

Ever since that day, in fact, since that repair alongside the road, the bucking issue in reverse has gone worse, and now the truck wants to rev up while moving down the road in 3rd or 4th gear. It isn't much, possibly 300 RPM, but it has bothered me. I can feel it jerk while shifting as well. One day last week I took a turn onto a side road it seemed to buck in possibly 2nd gear. That has only happened once.

I am planning to do a tranny flush and change the filter. Supposedly this is a new transmission on the truck, replaced at 60000 miles due to a leak that burned it up. The truck has 100000 now. Right before I bought the truck around 90000 the tranny cooler lines were updated and the fluid was changed.

Does this sound like a transmission issue or possibly a fuel supply issue?

Ben W.

 

have you already checked the trans fluid level?

 

Fluid level looks fine, it was right at the bottom of the hash marks. Still looked pink to me but it smelled a little "funny" so that is why I decided to do a flush.

Ben W.

 

The bucking is most likely the engine, not the trans.

 

Mark, are you thinking fuel supply like I am or injector related?

Ben W.

 

Either one. With a diesel the problem is always getting fuel into the combustion chamber.