Gearbox or rear axle whine?? Help!

[uk01gt]

There was a thread that I found that asked the same question, but was a manual car, and he had a bad clutch bearing.

Mines a 2001 Auto GT, that has started to develop a whine primarily on throttle lift off, and from higher speeds. It's really difficult to hear where's it's coming from, but it's definately a whine and not a grumble. It appears to happen more at higher speeds (the car sounds totally normally up to about 40), and in or out of OD makes no difference.

The gearbox changes fine, fluid is good, and I checked the axle fluid and it was full. (Sidenote on gearbox :- I can hear my TC spoolup from a standstill, is that normal?)

The car is stock drivetrain wise, I don't thrash it, and it's done a total of 30k miles. I drive it every day for work, and it's only recently started.

Can you guys think of any checks I can make to help out a diagnosis?

Thanks,
Paul

 

[codyGT]

Try to figure out if it is a Differential noise or a Transmission noise first.

Since it sounds like it changes with throttle you could have a carrier or pinion bearing going bad. They will have more/less loads on them during different throttle positions.

 

[uk01gt]

Try to figure out if it is a Differential noise or a Transmission noise first.

/QUOTE]

I guess that's what I really need the initial help on. Since I'm assuming I can't knock into neutral at 50 to see if it changes the noise. Are there any non invasive checks I can do on the diff?

How the hell can the gears/pinion etc. get shot after only 30k miles?? Ok, I did 5 runs at the strip in the summer, but that was 4-5 months ago..the noise only started in the last week.

 

[jrc_03_gt]

SORRY THIS IS OFF THE SUBJECT . I had to ask you I noticed you are in england. Do mustangs get lots of love in england? Are they rare over there? Do you have mustang clubs too?

 

[codyGT]

Is the diff. fluid ok and full. It doesn't take but a couple of seconds for a roller in a bearing to score the cage/race if it gets dirty or dry.

Putting it in neutral won't hurt anything, let off the throttle and coast is the noise still present? That will take the trans. out of the formula then. Depending on whats wrong some bearings make noise with load and some without.

 

[uk01gt]

SORRY THIS IS OFF THE SUBJECT . I had to ask you I noticed you are in england. Do mustangs get lots of love in england? Are they rare over there? Do you have mustang clubs too?

Yes they are rare over here, especially in yellow. I only know of three others. In general, I would estimate that there are less than 40 or so 1999-03 Mustangs of any variation in the country.

There is a mustang club for the UK, but they're pretty much dedicated to the 60's-70's model.

 

[uk01gt]

Is the diff. fluid ok and full. It doesn't take but a couple of seconds for a roller in a bearing to score the cage/race if it gets dirty or dry.

Putting it in neutral won't hurt anything, let off the throttle and coast is the noise still present? That will take the trans. out of the formula then. Depending on whats wrong some bearings make noise with load and some without.

The diff fluid is full, and didn't appear to be bad. I was under the impression that running an auto trans on coast/neutral was toast for the trans???

 

[40th GT]

Nope, no damage will be done, just don't neutral drop it. As in, rev the car in neutral and drop it in D.