the truck-
1997 f250, 4.10 l/s, 5 speed, 195k miles.

the problem-
intermittent vibration that starts at 35 mph. sometimes its so bad i can see the bed shaking and sometimes its as smooth as glass. sometimes i feel the vibration in the steering wheel and not the rear end, sometimes the rear end and not the steering wheel. when i have a trailer hooked to it the rear end bounces up and down like i have a tire with a bad spot on it.

when the problem started-
the right rear axle seal broke at some point between ohio and tennessee and gave me a nice undercoating. the vibration started about 30 miles from home, but who knows when the axle seal gave out.

ive checked everything from bumper to bumper and fixed anything that was worn or broken, but it did nothing for the vibration. new ball joints, rotors, brake calipers, brake pads and wheel bearings in the front. new tires all around(had them rebalanced 4 times and rotated them). u joints and tie rod ends are good. new shocks. i changed the gear oil and replaced the axle seals in the rear. i dont think it would be a wheel bearing because its not a continuous vibration and there's no noise. it does it in neutral too, so probably nothing drivetrain related.

 

I had almost the same strange vibration. It came and went at times with no repeatable conditions except when taking the same high speed right hand curve on the e-way. The only thing I found was a little extra movement in the carrier bearing on the rear drive shaft. Changed it and it disappeared.

 

I had same symptoms as you both described. Occured right after I rotated tires.
Had the tires re-balanced and no more bounce, vibe, shimmy, nothing...

 

ill check that tonight and see if it has any play in it. another thing i had thought about was that maybe running it without much gear oil in it may have fried the clutches in the L/S. i dont know if that would cause a vibration though. the L/S still works, but when i checked the gear oil the other day it looked like it was full of glitter. i used valvoline synthetic gear oil and the bottle said not to use the L/S additive. i talked to the ford garage here in town and they said the same thing. ive never heard of not using the additive, but ive always used conventional gear oil before.

the vibration didnt start until i noticed the axle seal was broken. so either the seal broke, drained some fluid and whatever part was affected by the lack of fluid caused the vibration or the vibration damaged the seal and had nothing to do with the fluid at all. the vibration started about a year ago and all the stuff i fixed was done at the same time. i took it to a couple of garages and none of them could figure it out either, so ive kind of been driving it the last year hoping whatever it was would just break. it hasnt gotten any worse and nothing has broken yet, so now im starting my search all over again.

 

that was one of my first thoughts too. i had just put brand new tires on it about two weeks before that though. i took it back to the tire shop 4 times and had them rebalance the tires. i even had them break them down and swap the tires/wheel around and it still didnt fix it.

i was hauling a car back from ohio and one of the tires on my car hauler blew out. when i stopped to change it i noticed the rear end oil all over the underside of my truck. i was almost home, so i just figured i would take it slow the rest of the trip and the rear end would be fine. when i pulled out from changing the tire on my car hauler the truck started bouncing pretty bad in the rear end. i figured the tire i just put on the car hauler had a knot on it or something because it was just an old spare and it hadnt had the first vibration before that. the vibration was still there after i unhooked the trailer, but it wasnt as bad. without weight on the truck its not too bad, but it gets worse with a trailer hooked to it or a lot of weight in the bed.

 

update-

i checked my l/s today and its not working. it was working before i changed the gear oil. im going to change the oil again and put conventional back in it with some additive and see if that helps it.

 

If you want to make the l/s clutches grab again then do not use any additive.
The additive, friction modifier, doesn't' make the l/s work better. It actually makes the clutches slip a tad easier to help reduce chatter in tight turns plus it increases l/s clutch life.

 

thats what i was thinking too. the rear end guy at the ford shop told me i was using too thick of a gear oil and i needed to change it, so ill probably go ahead and change it anyways, but leave the friction modifier out. some guys on here recommended 90/140 synthetic but the ford guy told me to use 80/90 conventional. when i talked to him we thought maybe the clutches werent slipping and that was what was causing the vibration, because it seems to be worse during and right after going through a turn.

 

If you are pulling the diff cover you might want to have the gears, bearings & clearances checked. Might as well put in a set of l/s clutches while you are in there.
I use 75w140 syn, it comes with a small amount of the additive already in it. Many guys use regular 80w90 gear oil with good results.

 

Anyone have the part number for the carrier bearing? I have a vibration I can't get rid of and about 1/4" play in the center bearing...

97 F250 CC 4x4

 

Check the bottom of this pag of this link.
Then see if they can assit.
http://www.drivetrain.com/parts_cata...ent_parts.html
Other than that I could not find one. Reason is that mines acting up too.

If you find it let me know.
Thanks
Rocky

 

TIMKEN PN HB88508AA. It's the same PN for BCA and National too.

 

Thanks Jim I found a pic. Now I have to see about pricing.
Rocky
<TABLE cellSpacing=10 cellPadding=0 width="100%" border=0><TBODY><TR><TD id=partnumber colSpan=4>HB88508AA 2</TD></TR><TR><TD colSpan=4>Description:
Timken® Ball Hanger Bearing</TD></TR><TR><TD width="25%">Weight:
1.2 lb</TD></TR></TBODY></TABLE>
Timken Torrington Fafnir Online Catalog: Automotive & Heavy Duty Truck Bearings, Sets and Kits: Application Specific Bearings: Drive Shaft Center Support Bearings:

Thats what I was looking for.
Thanks Jim
Now lets see if your rep'ed out. Yeap they would not let me rep. Rep him BAD DOG.

Rocky

 

Thanks guys! I tried to rep Jim, but was denied...

Rocky- looks like they have them at several places, all around $33. Amazon & RockAuto have them...

Jim, I'm thinking of doing the drive shaft u-joints too. Would you happen to have a spicer PN for those?

Thanks,
Craig

 

I think I will try and thread the hole on the side and install a grease zert on the one I buy. something to think about. God Q on the U joints. I'm looking.
Rocky