I have a vibration that starts at 35MPH up tp abput 45 MPH, and seems constant at that speed. I feel it in the seat, and also the steering column vibrates up and down a little (but not a side to side shimmy like a loose front end piece). I saw many posts about TC shudder, so first I changed the tranny fluid and used Mercon (not V), since that is what the dipstick called for. No help. Then I saw many threads about Mercon V, so I did another fluid change to that (including draining the converter and the cooler in the radiator). Again no help. Had tires rebalanced, no help. I found what seemed to be some side-to-side play in the driveshaft where it meets the tail of the tranny. I saw references to the bearing possibly going bad, so I ordered a new tailshaft assembly. When I installed it, the old one did not look too worn, but I replaced it anyway. No Help. Arghh... One thing I did notice that while I had the tailshaft housing removed to replace it, I could move the tailshaft up and down quite a lot (like maybe a 1/4 inch or more). Does anyone know if that is normal? I have no experience or knowledge of trannys, but I am wondering if I was actually seeing the root of the problem and didn't know it. If the tailshaft play is normal, does anyone have other ideas? U-joints (though they seem ok to me)? Something else?
Truck is 97 F150XLT 2WD reg cab long bed, 82K miles

 

you can move the yolk in the tail shaft 1/4"???? if so, that's too much. The tailshaft itself will move a bit, gets supported by the yolk bushing once it's together.

Ujoints can look good and be bad. I've seen them look perfect and couldn't budge them at all, but they were trashed, Ujoints are cheap. I would replace them anyways.


With the symptoms you describe, at the speed, and coming/going like that. It definately sounds like Ujoints.

 

I had a shudder with my E4OD and changed the fluid / filter and that made a major improvement. However I could still feel a noticeable vibration at speeds above 30 or so. My U joints felt fine while installed, but I picked up replacements anyway.
When I removed them they were shot. The needles in the rear joint were GONE! And I could not detect that with the shaft installed.
The front joint was trash as well but not quite as bad.
After replacement the vibration is completely gone.
I had 115K on the joints.

 

Thanks for the feedback... How difficult is it to replace u-joints? I can get the shaft out easily (I had practice on that), but do you need a special press or anything to get the u-joints out? What holds them in? The last vehicle I replaced u-joints on was an old Chevy truck, and they were rusted quite badly and needed a lot of beating and torching (and cursing) to get them out.

 

slfalco,

This is a u-joint press kit. Very easy to use and you can rent one at just about any auto parts store. A large vice works as well. The u-joints are held in by clips. Remove the clips with a pliers and use the press or vice, (with one socket small enough to push on one side of the u-joint, and the other large enough to catch it) and press the u-joint out of the driveshaft/slip yoke/companion flange.

 

Excellent, thanks for the advice, I never saw this press kit before, but it seems like just the ticket. I'll see about tackling this over the weekend....

 

Just an update.... I tried to rent one of those U-joint presses, most places told me they never heard of it. I finally found one at the Advance Auto Parts store, I ended up buying the thing for about $90 (it will do ball joints, u-joints, and brake anchor pins). Can't have too many tools you know... I replaced the u-joints (which didn't seem too bad), and that improved things a lot, but not completely. I then decided to really go over the front end. I could not find anything loose, but I saw grease fittings on the Idler arm, so I greased that. At this point most of the vibration is gone, although I still feel a tiny bit at like 42MPH. Since it is much improved, I guess that is as good as it will get.... Hard to say the definite cause, since I tried so many things, but persistance does sometimes pay... Thanks for the suggestions everyone....

 

repacking the front bearings?...just a thought

 

Your problem may have something to do with drive shaft balancing, matching of the drive shaft with the pinion gear (in diff) flange, or matching of the drive shaft with the tranny output shaft. All of the above should have supposedly been done at the factory in an attempt to eliminate any potential vibes caused by excessive runout conditions.

My 98 F150 SC 4x4 has the condition you describe. I've replaced tires, tierods, had front end alignment, wheel balanced, new u-joints, flush trans twice, all with no success. My rearend is quiet as a mouse, so I don't see any problems with the pinion bearings. I've indexed the drv shaft several times on the slip yoke to tail shaft end with no increase or decrease in vibe frequency. But when I did the same at the rear of the shaft, where it bolts to the pinion universal flange, I felt huge changes in vibration. Oddly, there is no evidence that my shaft threw a weight. So, I thinking this condition may have been there for some time (I'm second owner).

I'm gonna try the hose clamp field balnce procedure. let you know how I make out.

98 F150 SC XLT E4x4 Offroad, 120K, 3.55LS, 4R100,

Mods: None

Bad Stuff: door cracks, leaky rear window, sticky domelight/dr ajar relay (GEM module), defective horn, cracked intrument panel lens, body dimples, and of course the drive line vibe.