Question About 3.73 Rear End ??

[edogwv]

Im experiencing a vibration while traveling about 65+ mph, and believe that The source of the problem has something to do with the rear end. I replaced the Universal Joints on the driveshaft, recently, but one of them seems to have gone bad again. The yoke, (I believe) where the driveshaft bolts into the rear end has a little bit of a side to side movement. Is this normal? Is there a bearing inside that needs to be replaced?

After getting buried in a mudhole and having to leave it over-night, IM suspecting that water got into the rear end and maybe corroded something. Also, what gear oil weight should be used in this rear end?

Thanks in advance,

edogwv@hotmail.com

Any suggestions would be appreciated, my friend and I are thinking about digging into it soon.

[Ray Lobato]

edogwv,
What year is your truck?
also did this vibration come before you were stuck in the mud or after?
If you can give us as much infor as you can, maybe we can figure this out.

[edogwv]

Thanks Ray, It's a 92 XLT with a Manual Transmission. I've got about 145,000 on the odometer.

-edogwv

[Scott B.]

edogwv,

Use 80W-90 gear oil in the rearend.

It sounds like you need to pull the diff cover, drain the fluid, and replace it with fresh oil. You could have water and mud in there.

When you replace the u-joints, did you re-assemble the driveshaft and yokes in the same/correct alignment? Did you attach the driveshaft to the rear end in the same position? The factory balances everything when they build the trucks - if something is misaligned, that could be the source of your vibration. If your u-joints are out of phase, that could be another source of vibration.

[edogwv]

Well, it wasn't the U Joints, nor bearings in the rear axle. It was something much stupider. The huge nut on the end of the axle yoke had somehow worked itself loose. I took the nut off, cleaned it, and torqued it back on with locktight. I dont think anything was even really damaged. I wonder how that stupid thing worked loose? I dont think anyone has ever messed with that bolt.

OH well, thanks for everybody's help.

[Scott B.]

How tight did you torque it? That nut compresses a crush sleeve, which sets the preload on the pinion bearings. The crush sleeve won't start crushing until it sees 180 ft-lbs, then you want about 20 in-lbs of preload to start the pinion turning.