greetings!
my '98 Detroit Locked 4R has developed a noise - and a slight vibration...around 55 and above - def coming from the rear - DEF NOT the tires....put it in N and the noise/vibes go away...

known issues - wheel bearing seal on P/S leaky....however, the DIF is good on fluid - it's not low...I suppose it could be the wheel bearing, but it didn't sound like this last time it went out...

U-joints are well greased, however on last oil change, the 2nd toward the front zerk from the rear took hella amounts of grease.

suggestions on what to do next to pinpoint what is is?? Obviously, i'm going to the tech section and figure out the wheel bearing seal next.

thanks in advance,
Aaron

 

I am going to say that the leaky seal allowed the oil to wash the grease out of the bearing and that is the cause of your vibration. Same thing happened to mine. Have a new bearing pressed on when you fix the seal.

 

If the noise goes away in neutral then it's not the diff or the axles. It may be u-joints or drive shaft joints. The u-joints and double cardan joints should be firm and not floppy. The second zirk from the rear fills the spline shaft that connects the two drive shaft parts together and will build allot of pressure if over greased. You can probably unscrew that zirk and if there's too much pressure the excess grease should squirt out of the zirk fitting hole.

 

Yep its def not the diff or the axles. When my wheel bearings went bad the vibration/noise did not go away when in neutral.

 

thanks guys - it's the U joints....bone yard hooked me on a 43k rear shaft for $125....swank!

 

how often did you grease them? or are they the sealed ones?

 

i was fairly religious on the grease...when i was wheeling...in the last year i haven't wheel'd much, so i was only on the zerks every oil change.

179k on the the OG u joints... plus they were subject to the Detroit - i was told that the detroit would chew thru U-joints when i had it installed....

a