F250 Tranny ?

[tech701]

Here goes. I have an 03 F250 with a 7.3l and a 4r100. The truck also has a what I think is a 4" lift with 35" tires that had been installed prior to my purchasing the truck. When I start foward motion from a dead stop I encounter a noticable shimmy (shake). I initially thought this was axle wrap, that the pinion angle was just going way skyward and causing the driveshaft to vibrate due to the universal being stuck in a tight angle. But the more I drive the truck the more I think it is from something else b/c I also have started noticing it when I let off the gas while applying no brakes. The shimmy is also strangely not as apparent when under hard acceleration from a dead stop. What could be causing this? Could it be the tourqe converter? The tranny itself shifts nice and firm with no noticable slipping and my tranny temp guage is cool, normally less than 150 degrees.

[SCUFFY828]

need to try and shim center support down about half inch if not done and check u-joints also

[Maintain]

Carrier bearing would be my guess... I have a simlar problem that isn't bad enough to go changing things... slight shimmy when cruising at 45, all other speeds are fine until braking then things shimmy again but I think that's my rotors...

[tech701]

When you guys say carrier bearing you're not referring to the bearings inside the rear diff are you?

[lilredpowerstroke]

No its the carrier bearing in the two piece driveshaft. Most people say that you should shim the carrier 1/2" for every 1" of lift, so if you have 4" then you need 2" of shims. You could also try different shim heights to dial it in perfect.

[Nick]

I am wondering what I can use for shims. I put a lift on my 1996 and did nothing far as that is concerned. I am having a really bad vibration above 62 MPH. and it does not go away. The vibration is hard in the seat and it will shake the tar right out of you. If anyone has any ideas please let me know. I think it is the rear wheels but sure and looking for some help.

[djsdiesel]

I had the same problem it was dry U-joint it sure was nice of ford not to put grease zerks in.

[ipz2222]

# 1 cause is dry or stiff ujoints in driveshaft. If this is 4x4, you BETTER get it fixed. It will crack the trans case . Mucho denario