I have a 1996 F150 with 94000 miles. The vehicle has the towing prep package (bigger radiator, transmission cooler) and the 5.8 engine. It is an XLT.

I have been noticing some slight shuddering at highway speeds (65-75 mph or so) and have noticed that this shuddering issue is far worse when I am towing my boat, up hills in particular. The truck does not appear to have a "perfect" idle but the idle charachteristics have not been terrible either. I have the truck scheduled to be worked on tomorrow and when I told the technician what is happening, he said that it sounds like it could be either the tranmission slipping or the engine misfiring.

I am relatively familiar with engines, but transmissions scare and confuse the crap out of me. Anytime I hear about transmission problems, I immediately think of huge repair bills or a transmission replacement altogether. If there is such a thing as a minor transmission problem, I am not aware of it.

Can anyone who has dealt with a similar situation, or knows the behavior I am speaking of, let me know what they think of these symptoms, and maybe a little bit of insight as to what I should expect them to find?

Thanks,
JH

 

I had the same kind of shudder in my 95 and the mechanic said it was the converter not locking up completely. He added a bottle of Smartblend tranny additive and it immediately went away.

 

it could be rear driveshaft u joints that was the first speed "area" i noticed a problem in my truck. check out this thread

https://www.f150online.com/forums/sh...d.php?t=201962

new joints fixed mine. put truck in park and try to loosen bolts holding rear driveshaft flange to the rear pinion. or maybe u might have to put it in neutral and set e-brake ( i dont remember which way showed the wear better) i saw a dramatic wear as the driveshaft rotated for a while before the pinion did. replaced joints fixed the problem.

 

I am noticing the same thing in my 94. Driveline vibration turing normal acceleration....running fine then this vibration....seems apparent only in the gear just below OD.
Wondered if it was the TQ myself. The truck is relatively "new" to me, I picked it from the neighbor...he had the tranny rebuilt 8k or so ago, and I was wondering if the trans place put the OEM fluid back in. Does it need a friction modifier?? Took a peek at the fluid, and of course it looks great, Not sure what trans is in it....

Door codes are:

MB :133
Type: F155
Body64
Trans: U
Axle: 18
Springs: KG

Think just adding an OEM friction modifier is going to "fix" the issue?

Thanks in advance for the input.

 

Nothnbutrouble-
You have a 4R70W trans, and 3.08 gears in an open diff.

 

Yes, the 4R70W needs a friction modifier in the oil.
You need to drain the transmission, torque converter, and oil lines to the front and then replace with MERCON V only (preferably synthetic if you can afford it). Do not use MERCON like the book and the dipstick says, it has changed.
Do not let any body tell you any different, they will try.

MERCON and MERCON V will not mix.
Do not let any body tell you any different, they will try.

NOTE, THIS IS ONLY FOR THE 4R70W (AODE) TRANSMISSION

It would be bad for the others.