Drive Shaft Wine....OK "Whine"

[oldmako]

My ride has a whine which begins around 40 mph which seems to emanate from somewhere in the drive train. I say this, because when I let off the gas at 50ish, the noise immediately changes pitch/tone as the load changes on the car from push to shove. There is no vibration associated with the noise. There is no change in the noise if the car is shifted into neutral at 40ish with my foot off the gas. The trans shifts smoothly and without any abnormal indications.

The noise seems to come from the front of the car, but as with most noises it's really difficult to tell. I have felt the front hubs after a long high speed run and there is no heat apparent, and no vibration through the steering wheel.

My mech seems to think the coupling at the trans is bad. I can't help but think the bearing in the shaft is the culprit....as it's a bearing growl sound. The bearing is available for $110 bucks. The front coupling is not available without buying the entire drive shaft.

Has anyone run into this snafu? If so, how much work was involved? In looking at the FSM it doesn't appear too terribly difficult, but I'd bet ten bucks there's more to it.

Any info appreciated. My search revealed little.thanks.
Modified by oldmako at 10:43 AM 1/31/2008

[qship96]

Have you ruled out tires and wheel bearings?

[oldmako]

Tires are brand new. There is no vibration at all in the steering wheel at speed.No heat at hubs. Short of disassembly, how else can I verify the bearings condition?

The way the noise comes and goes with the application of throttle leads me to believe that it's in the drive train....but I am just fishin' at this point. Any ideas appreciated. Thanks.

[qship96]

Did the whine occur before you put the new tires on?check wheel bearings by removing wheels and hand rotate hubs,should feel smooth turning-also feel for any looseness side to side/up/down.

tires can whine without feeling any vibration in steering wheel,as it is not imbalance that causes tire whine-more like tire tread design or poor quality control

[oldmako]

It was present before I hung the tires...but not quite as prevalent. I had the car on jacks last week and spun the wheels by hand (without taking the tires off) and there was no noise or roughness apparent. I know this is no substitute for manipulating the bearing itself. With previous cars a bad bearing manifested itself through wheel shimmy (assuming good tires and balance), so that's why I leaned that way. But I see that this car has a larger and beefier bearing.

Is it possible for a bearing of this design to start to scream without affecting it's "feel" through the steering wheel? Obviously I'd much rather hang new wheel bearings on it.

The car is in the shop for the strut work at this time so I can't go out and grab it at this time. Many thanks for your input.

[maxnix]

Similar problem to correct on my wife's. I will power up while it is on the lift to see if it is the driveshaft bearing. I am pretty sure it is not a wheel beraing, but have not examined all four.

[oldmako]

I wonder if it's possible to put the car on a lift and run it in gear 1500-1800 rpm while someone puts an ear near that shaft bearing. Seems feasible, although I'm not sure how safe.

How long has her car made the noise?

I figure that eventually it will get so bad that it will be easy to pinpoint, or it will fail outright. But I'd rather get it fixed before it gets more expensive, or fails on the highway. Besides, it interferes with my stereo and the sweet sounds the engine makes as it nears redline.

[maxnix]

I wonder if it's possible to put the car on a lift and run it in gear 1500-1800 rpm while someone puts an ear near that shaft bearing. Seems feasible, although I'm not sure how safe.

That's what I am going to do after hand checking all four wheels.

Wife says it is annoying her.

[Q45tech]

Listen to diff front bearing with a stethoscope.

Record and spectrum analyse the frequency correlate sound frequency with rpms.

[oldmako]

WAAAAAAAAAAYYYYYY over my head as my frequency correlating spectrum analyzer is on the fritz, but thanks for the reply!

I guess I'll just have to wait for whatever it is to fail.

[Q45tech]

Since you can hear the whine so much easier than measuring a SUBSONIC vibration.

We usually put on a lift with driver controlling wheel speed [per instructions] and another technican moving front to rear sampling the sound locations for intensity with ears then stethoscope.

IF it goes away lift off ground then the tire or bearings are the culprit.

Why you always take it to an expert tech who has a partner and who hears similiar problems every week.

http://www.spectra.it/download...c.pdf

[oldmako]

I agree completely. However I don't have access to a lift or a partner at this time. Working in a condo lot has significant limitations. I am an ordinary shade tree geek trying to repair my own car because I enjoy fixing stuff, and I enjoy saving money so I can blow it elsewhere (or save it for the next issue). I've done most of my repairs for the last 30 years and I'm trying to get up to speed on this one. It's significantly more complicated than anything I have owned/wrenched to date, but many repairs are still within my ability.

In the final analysis, I may end up taking the car in and doing as you suggest. But in the meantime I'd like to try and diagnose it myself so I can be sure that the correct part is changed out. Most of us know someone who has spent good money at a shop only to have the problem remain. I don't want to just toss cash at this and that and hope I hit a bullseye.

If I ever win the lotto, I can pretty much guarantee that my next domicile will have a large garage with a lift.

[goody90q45]

It was present before I hung the tires...but not quite as prevalent.

Just for kicks check the tire pressure cold. They should be about 32psi depending on the tire. Over-inflation can bring out some odd, loud noises.

[oldmako]

That's been done. Makes no diff on the psi.

Thanks Mike.

[RAP]

Tires are brand new. There is no vibration at all in the steering wheel at speed.No heat at hubs. Short of disassembly, how else can I verify the bearings condition?

The way the noise comes and goes with the application of throttle leads me to believe that it's in the drive train....but I am just fishin' at this point. Any ideas appreciated. Thanks.

Just a thought, have you checked the differential fluid level. Gear boxes will whine if low on lube.

Jack

[oldmako]

I have not. I purchased two quarts of Mobil 1 Synthetic to change out the fluid two weeks ago, but I was unable to remove the filler plug. I chose not to drain the case if I couldn't get the new oil in!

It has to do with the juxtaposition of the filler, exhaust tubing and the limited amount of lift I can get from my jacks. I just couldn't get any real leverage on it. I plan on attacking it again soon with a left handed smoke changer and tractor beam setup, along with some additional tools. It sure seemed like a simple enough task when I went under the car, but I was stymied. I shot some aerokroil on it, so I am optimistic that it will come out next time.

Thank you for the suggestion.

[maxnix]

When you see it how easy it is done on a lift, you will cry.

So is the fuel filter, so do it then also.

[oldmako]

I know. The limiting factor in the plugs removal was the parking lot itself. I'm sure that on a lift, I could probably sip a beer while removing it. Oh well, it is what it is. I'll get that mother out soon enough. It would help greatly to eliminate possible sources of drive train harmonics.

[RAP]

A sky hook would be an asset also for getting things up in the air. Then use the left handed smoke changer.

Jack