Greetings from SoCal,

I've been fixing a lot lately and I'm geting to the point of addressing this high pitched whine that starts ~40mph and will cease ~90mph.

My most recent smog test, while the car was on "the rollers", I noticed that the rear drivers wheel follows a slight eliptical pattern - not round.

The rear wheel bearings are original. I change the differential fluid every 60K miles and use synthetic 140 weight. The center bearing / bushing combo, all three u-joints and tailshaft bushing / bearing are good. I have an auto tranny.

The whine will stop if I take my foot off of the accelerator at anytime during the whine and coast. I'm thinking that I'll have the rear wheel bearings replaced, which should fix the eliptical pattern situation and then proceed to other possibilities if the whine is still there.

Any thoughts or experiences are appreciated.

Stormie - '88 240DL, 537,000 original miles, original owner, second tranny. HD Bils, TME springs, full poly bushings, adjustable panhard and torque rods, upper & lower chassis braces, power mirrors, power windows (switches in the center console!)

A slight whine on drive, disappearing on overrun, sounds like classic long term crown wheel and pinion wear. At your mileage it's not really surprising - mine does it a bit at only 375,000 miles.
Axles will go on forever doing it, it's really just a question of how much noise you find acceptable.

Rear axle bearings are really tough. Could the eliptical path be from a bent wheel? Seems more likely to me. Can you pull the axle shaft and check for it being a bit bent?

Question re: diff. lube. Why the heavier weight? I think the spec calls for SAE 80 to 90.

Sounds that vary with accelerate - coast - decelerate with engine braking, and maybe with left or right turns, can be rear end bearing related, but not certain which one(s).

Could it be that the sound below 40mph is of a frequency too low to pick up?

Good Luck,

Bob

:>)

Thanks, Bob

The rims are original and I've never been in an accident or hit a curb or other object to consider a bent rim.

The fluid is Valvoline, 85W-140W.

I'm going to the shop for this one and I'll have Sonny check for a bent shaft. He quoted me ~$325 to replace both sides. Not a bad deal, and i don't have to pull 'em and then go to a machine shop for a R/R.

I'll let you know what happens....

Stormie

If you deceide to have them changed I would consider bringing in a new set of parking brake shoes. The old ones need to be removed to change the bearings.