How to get rid of differential noise? (1 Viewer)

[MikePL]

Unfortunately I have never approached tearing apart a diff.

The problem is that I hear a 'wooooo' sound when going over 40mph. The sound comes somewhere from the driveline (probably any of the three diffs). The PO was driving (on concrete) with the viscous coupler seized for a few years and this has caused excessive wear on the diffs probably.

A 'woooo' sound probably means play on the sprockets, which means wear, which makes matters worse. What can I do to stop the 'erosion' process and save the diffs? A heavier oil? A ceramizer or other magic solution? Beer?

 

[Romer]

Typically, with any driveline problem, you have to narrow to the source of the noise. First step is usually drive with one drive shaft at a time and see if that makes a difference. This will require the CDL switch.

 

[Tools R Us]

Typically, with any driveline problem, you have to narrow to the source of the noise. First step is usually drive with one drive shaft at a time and see if that makes a difference. This will require the CDL switch.

This is the best place to start. A CDL switch will make it easier, but isn't required. Shift low range, make sure CDL is locked, pull the locker fuse or unplug the CDL actuator, shift high and drive.

 

[sseaman]

have you changed fluids in the 3 diffs yet? if not go ahead and see how the fluid looks that you take out

 

[MikePL]

The fluids have been changed around 10 months ago. All done at the dealer and all documented. I have the possibility to lock the center diff and I will try to narrow down the noise. Although from my observation it seems that the rear diff is the problem.
The symptoms are:
- decelerating- no noise
- hard acceleration- no noise
- cruising- noise

OK, so let's assume that I've narrowed down the problem to one diff (or all of them). What should I do next? Any magical solutions?

 

[Romer]

Is your wooo more like a whistle and coming from the rear?

If so, it's not the diffs but the exhaust.

 

[MikePL]

No, it's no whistle. It sounds similar to worn bearings, but worn bearings make noise all the time obviously. This sound is a moderately pitched sound, not bass and not whistle either. It appears/disappears even with very slight variations in engine load. For example I am going at a constant speed and there's sound. Even if I let off the gas a little bit, the sound disappears, only to engage a second earlier when the truck has 'settled' at the new speed. Definitely no exhaust problems.

 

[tommy854runner]

I think I am having a similar problem. I can feel the wooor, wooor, noise in my flooboard slightly around 40-45 but gets very loud at almost exactly 75mph to 82mph then I get so fast I can't hear it anymore. I also hear a buzzing metal on metal noise when I decelerate at around 45mph and up which I believe is because the exhaust brackets are seperated in 2 spots but the exhaust is still holding up ok. I plan on racking the truck this week and grabbing a tech's stethoscope and trying to pinpoint which diff it is or t-case I will post my findings when done, anyone else got any advice on this matter, my wife is rubbing it in my face that there is something wrong with the cruiser after I spent months convincing her they are indestructible!!

 

[Romer]

Then the drive shaft method is the best thing. If it goes away with the rear,. have the U joints checked and make sure it's balanced.

If that doesn't fix it, try removing the front.

If that doesn't do it. Try putting thicker gear oil in the Tcase and see if it changes the sound at all. You could do this step first as well.