2002 F150 SuperCab. 93,000 miles. no mods. 4.6l,Rear wheel drive. Developed a vibration that is felt in the seat. It is between 38 and 42 mph. Again felt above 65mph. Seems rotational. Steering is solid. Rotated tires front to rear no change. Even bought new BFG Long Trail Tour. Drive shaft balanced and new u-joints. No change. New rotors and brakes front and rear. Even disengaged emergency brake. No change from rear vibration. Vibration is speed dependent. Vibration in gear or when coasting in neutral. Even put in neutral and shut off engine, vibration continues. Question is could this be an extension housing bushing, I have a slight leak from the rear transmission, fluid doesn't drop to ground but is slung onto bottom of cab. Does the driveshaft turn when the truck is in neutral and the engine off? Truck has never been wrecked. Local Ford wants $300.00 for estimate.

Tires Road Force Balanced one week ago.

Thanks,

John

 

have you checked shocks and the rubber bushings top and bottom, and that the bolts/nuts are tight? (and the welded brackets) Also theres been a few reported cases of a broken leaf spring, you prob. won't casually notice it. These things set up harmonics at diff speeds, and of course it could be a number of things of which you've already checked or replaced. I doubt the tranny bushing is the cause unless it is truely worn out. You can't turn the driveshaft in nuetral with both back wheels on the ground. Do you have a 1 pc or 2 pc drive shaft? Maybe someone else will chime in also....rossford

 

The driveshaft is the single long aluminum shaft.
The shocks were replaced with Bilsteins when I first noticed the vibrations.
The transmission and motor mounts have been checked out.

 

if i understand correctly...your driveshaft will move in neutral with the engine off if it is still moving. i understood it as you were going 38-42mph and shut the engine off and coasted. if thats what you mean then yes. if your rear wheels are spinning, so is your driveshaft. fyi thats how you push-start a vehicle with a manual tranny. rear wheels and driveshaft spin, then when clutch is released while in gear, the clutch connects the engine to the rest of the moving parts to it turns the engine over.

 

Place rear truck on jack stands and ran up to vibration speed. The drivers side rear has a bad vibration. I removed tire and replaced lug nuts. Again up to vibration speed and same vibration. As I said before the rear rotors and pads were replaced with Wagner Thermoquiets. So now, The dial indicator points to a bad rear axle. I have never attempted to repair a rear axle. Seems straight forward. The question is there was no noise and the bearing seems tight, no play at all. What else could be the problem? I don't think that the truck was ever wrecked.

Thanks for your time,

John

 

try checking the bearing on the pinion gear of the rear axle, i have been told that is the problem. not 100% sure but work with a guy who says he worked for a place that fixed that sort of vibration in 97+ f150s. worth looking into...

 

Replaced the Drivers side rear axle. The harsh vibration at high speeds is resolved.
Thanks for everyones help!

John

 

this sounds a lot like my problem. i thought it was a misfire but no matter what i do i can't get a light or code to pop up. seems like it started after i replaced the axle but i wasn't sure.

does anyone think driving with a messed up axle shaft could lead to further harm down the road? i was going to replace the entire rear end anyway due to the axle shaft replacement being caused by a seized bearing.

 

I just got done with my commute from work and noticed the vibration my truck was giving off slightly escalated. i am pretty sure that the brakes do need to be checked cuz of the vibration while braking but today i noticed specific vibration felt with easy acceleration between 44-47 mph and most significantly at 52mph. truck is 4.6l 4x4 2002. called my shop and they asked if a light was on, i said no. 15 minutes later my service engine light blinks five times and then dissappears. owners manual says possible engine misfire. any and all advice would be greatly appreciated thanks.

 

2002 f150 2 wheel drive 4.6l how to change transmission

 

Okay.

 

When you had this problem, did the vibration get way worse when you let off the gas at high speeds (70+)? Your problem sounds like mine, except for that key piece...