dj7007

Hi Guys,
Ive searched through some of the threads on the whining issue and found nothing that matches my problem. Ive had a faint whine from the transmission (not differential). Not related to the air con as some people have said. I hear it mainly in the higher gears, and at low revs/6th gear its clearer. The whine comes when i accelerate, if I take it out of gear the whine stops. There is 21k miles up on the clock. Anyone experience this problem?
Thanks

SlickShoes

How have you made the determination that the whine is indeed the transmission and not the diff? Even in divorced applications where the trans and diff are 6 feet or more from each other, it's sometimes difficult to pinpoint the source- nevermind when they are mounted to one another.

What you're describing sounds like ring and pinion whine, which is exactly what I experienced. But, if you've positively eliminated that...

5knives

I'm experiencing a similar issue.

http://forums.corvetteforum.com/c6-t...-throttle.html

4th gear is the most noticeable and mine is also only while giving it throttle. Not even heavy throttle because the exhaust and engine noise drown out everything else. When just cruising with very little throttle. I hear the whine.

5knives

What did you do to remedy the issue?

hammert85

Its your Differential. I thought the same thing until I had the car on a lift and then had someone drive it as I stood under and listened. Drain your differential fluid and I bet you find metal shavings. Thats what happened to me. Time to upgrade.

5knives

Care to explain further? What happened and what was the cause? I already have a different gear set up and have had no issues for years. I honestly couldn't tell you if the noise has always been there or if it started after my last fluid change.

dj7007

Its only that if i put my ear to the gear shifter it sounds like its comin from that specific area, also when i put it out of gear when driving the whine stops. I would have assumed that if its the diff, it would continue to whine. Maybe i need to get it up on a lift to confirm.

dj7007

The diff oil was changed at 11k and at 21k miles which was only about 500 miles ago. Time to upgrade what, the differential?

REVAK

I am assuming you have a manual trans. Old school when the trans was directly behind the engine, noise on acceleration was usually input shaft / bearing related. Noise on decel was usually tail shaft / bearing related. No load coasting , less or no noise. Not sure if this would directly correlate to the rear mounted trans. or not. [ I retired from automotive back in the C4 days ]

torquetube

Just to be clear, the gearbox is in back, not under the gear lever, and the differential is bolted directly to it.

5knives

I assumed the same thing. Mine only makes the noise when it's receiving throttle input and usually only light throttle. If my foot is not on the gas, the noise isn't there.

Rick@RKT Performance

Here are some gereneral guidelines for the drivetrain whine/noise.

If the transmission gears are going bad, the noise will be pretty constant (load or coast) and at any speed.

The ring and pinion gears usually whine under a light load and most pronouced between 60-70 MPH.

To the OP, it sounds like a ring and pinion IMHO.

5knives

I know I'm not the OP but I'm having a similar issue.

So if it is the ring and pinion, is the noise an indicator of a problem or is it just a normal characteristic? If it is a problem, what is it and what needs to be fixed?

Thanks

Rick@RKT Performance

Noise is an indication of a problem. The wear pattern/backlash/improper break in causes the noise. Only fix is to replace the gears.

5knives

Wouldn't it do it at all time though and not only when touching the gas peddle? Isn't everything moving in there already? I can barely touch the throttle, I'm talking maybe an 1/8" of travel. Almost not even enough to get the car to accelerate faster, and I'll start to hear it. It does seem more noticeable in 4th gear and around the 60-70mph you stated though.

Hmm...

Rick@RKT Performance

The whine only happens during part throttle and not under WOT. The wear on the load side of the ring gear is what causes the noise ONLY on part throttle. I think the culprit is lack of servicing the diff fluid/overheating the diff or both. The diff fluid gets up to 230* on a constant cruise at highway speeds (65-70 MPH). With only 1.9 QTS keeping the diff cool without a cooler/heat exchanger, fluid change on a regular basis on these diffs are very important.

5knives

Ok. So what are we looking at in terms of actual damage? Full on catastrophe or just an annoying whine without any real harm? Obviously it's hard to be too accurate without seeing/hearing it but...

And before I forget, thanks for all the info.

Rick@RKT Performance

The diff will eventually get louder but I personally never seen a diff failure due to the whine. The worst I have ever seen was a diff that ate each other (ring/pinion gears) that has over .100" backlash. The specs on a normal ring and pinion gears are .009" backlash.

Anytime for fellow forum members!

Joe_G

Rick, great advice as usual. I have a diff temp gauge and will collaborate your comment re high temps when cruising on the highway.

How often/mileage do you recommend changing diff fluid?

Rick@RKT Performance

If you're not hard on the drivetrain, once a year is fine. If you ARE hard on drivetrian, more the better. Road racing guys change the fluids after every event. Drag racing guys should do it on a regular basis but that all depends on the frequency visiting the track.