2002 fx w/ 5.4 w/55k miles. 75% of the time the vehicle drags, just like your pulling a trailer. I'm constantly on the gas or it looses momentum asap. The rest of the time, it runs OK. Mileage tanked - 9MPG. Seems like the problem is in the tranny or TC because if I shift into neutral on the flat or down grade, the truck will mainatain or increase speed; otherwise, its like having a parachute....just slows real quick, even in OD. Brakes are fine. Experts say without codes showing, they can't or won't help. Any suggestions besides trading it in.

 

make sure your brakes are not binding.

 

Bring it to a good, reputable transmission shop, you're right, the problem most likely is in the tranny. "Do-it-all" auto centers tend to ***** the OBD scanner to tell them what's wrong, since diagnosing is usually a tedious process when you're got thousands of parts that could be the culprit.

Could be anything as simple as bad fluid, excessive sediment buildup, or a bearing could have crapped out and seized. If it's that, likely the fluid will be black and smell burnt due to the extreme heat that would produce.

 

Thanks for the advice. I noticed yesterday that there is 1/4" - 1/2 " of bare metal showing at the output shaft coming out of the rear of the transfer/tranny housing - right in front of the first u-joint. May or may not be related. Might be the imfamous yoke/slip problem that is often discussed in this forum.