Hi, I am new to the forum but, have been reading here for a few months soaking up information. Here is a little background on my new to me 1996 f150 xlt scab truck with the 5.8 engine 2 wheel drive and the vibration issue I am having and can't seem to fix. I hope someone can help me.

I bought my truck about 6 months ago, very little rust 115,000 miles. I love the truck but, this issue is beginning to drive me nuts !

I have a vibration in the vehicle at 65mph and above (mostly felt in the floor and seats and yes sometimes in steering but not always in steering?) truck is smooth all the way to 65 mph but, whats worse is when I decelerate the entire truck shakes badly!! the higher the speed I am slowing down from the worse it is, it's like the whole truck is bouncing. Here is the list of things I have done or have had done to bring my truck up to snuff.

plugs, wires, dist.cap n rotor, plug wires, aic valve, cleaned throttle body, all ball joints, all front wheel bearings, rotors, pads, calipers re-done, 4 new shocks, 3 new u-joints, center support bearing, drive shaft balanced and straightened, trans fluid done, diff. opened up inspected and fluid replaced, I had 4 new tires put on today, was a little better but not much. I've had the codes pulled with zero error codes, I've had the engine scoped, no issues. did the compression test all cylinders great minus cylinder 2 which is still in spec. was just a little under all the all the rest.......

I am doing trans mount this weekend as it looks separated from the rubber at the top, found it by lifting up on trans.

I am at a loss to explain the vibration issue and the severe shaking issue while decelerating and it seems to be getting worse, I do alot of e-way driving and need to solve this issue soon as I am moving out of state and need BigRed running right for the long haul. Please help I need some ideas as to what to look for here..........Thank you.

 

have u had the front end realigned? if not u might wanna try that

 

Yes I had the front end alignment done when i replaced the ball joints and had it rechecked when i got the tires replaced. The alignment is all good nothing out of whack.

 

check over the drive line when you are doing the trans mount if notting there pull the cover off the rear end and check that out

 

Maybe a bent rim?

 

i just bought mine a few months ago and it shakes but i believe its just a bent rim

 

I have checked the drive line multiple times even though it has new u-joints center support bearing and the drive shaft balanced and even made sure installation of drive shaft was proper since it was marked as to the position it was taken apart.

The cover for the rear end was pulled, everything was checked and new oil put in already.

I have considered the bent rim idea myself since I'm running out of ideas. still going to replace the trans. mount this weekend if I get time.

I don't think it's a trans. issue due to the fact that if I shift trans. into neutral while it is shuddering on deceleration it has no effect on the shudder whatsoever. getting stumped.

 

Check the wheel studs on the rear, i had a vibration like the one you described and its because i lost 3 studs off a rear wheel.

 

Does it shake on deceleration or on braking. If the former without brakes check your springs and ubolts in the back, also check your radius arm bushings. If braking, check your drums.