My 98 4Runner's rear end........I'm getting a whine from the rear diff that seams to be getting progressivly louder with time. It's got 116,000 miles. I've been using Mobil 1 75W-90 since 50K, changed at 100K.

Would a heavier gear oil help? Is the rear diff doomed at this point?

Thanks in advance.

98 4Runner
4 cyl, 5sp, 265/70-16 tire package

 

rear driveshaft u-joint(s)

 

"My rear end is making a noise...help. "

whats your diet like?

 

 

have you taken the truck off road or gotten water in to the rear diff? change out the diff fluid and see if that helps

 

At what speeds does the whine occur? Does it happen under a load or when deccelerating? I'm thinking what Wabbit is saying if the noise is constant and not the latter. If it's during decceleration or acceleration I would see about having the backlash checked.


edit: Forgot to mention... try to isolate the noise. For example, rule out tire noise by raising the rear end up and then CAREFULLY put it in gear and get up to speed. If the noise is still present then you know tires aren't the cause. Also you may want to go on a downhill ride in a secluded area, CAREFULLY switch into neutral and shut the engine off. You will no longer have power steering or a good set of brakes so use caution. If the noise is still present then you've ruled out a drive shaft problem.

 

lay off the late nite del taco runs

 

(insert anus joke)

 

To think that some one will be searching this and find stupid and irrelevant answers.

 

Noise goes away when there is no load on the diff.? louder under more load?

Loose pinion bearings.

They wear out a little. the shaft is allows to move a little. the gears mesh a little different and it whines.

You can rebuild the entire she-bang, but I would drive it until it howls.

Use the time to find a good used diff and/or consider this a reason to re-gear for bigger tires.