Gear Whine?
10-06-2006, 01:38 AM
#1
2nd Gear Member
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Join Date: Jun 2005
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Posts: 240
Gear Whine?
I had 3.73's and a track-lock (ford) installed and there was a whining sound that got really bad. Turned out it was my rear axle bearings and the shop said the sound was gone once they replaced them. I'm still hearing a (softer) whining sound and was wondering if it is normal to have gear whine with 3.73's or if it might be something else? I had a new driveshaft installed at the same time and was also wondering if you have to break-in driveshafts or bearings?
10-06-2006, 09:24 PM
#2
Join Date: May 2006
Posts: 14
RE: Gear Whine?
orion6g:
First, I hope you are enjoying your new gears and increased torque!
Second, this is the first time I have heard of axle bearings going bad on a gear install.
The axle bearing should be unaffected on a gear install,
unless the mechanic was very careless and pulled the axle out too far
or mishandled the axle.
Perhaps he meant to say it was the differential bearings?
New gears should not whine any more then your stock ones did.
Whining gears indicates an incorrect setup.
A slight “whine” usually is not a serious problem (but can be irritating),
Unlike a “load chatter” which could mean chunks of metal are destroying your teeth & bearings!
When installing new gears & especially new bearings
you should go through a run-in procedure to prolong
your gear set & minimize drivetrain loss.
If your mechanic did not tell you to do this run-in,
then he probably did it for you.
The first 2-3 min is usually done under no load, i.e. while it is on the lift.
Then you need to drive at normal speeds for 5-10min, and then let the diff cool down
for ½ hr or more. You need to do this 2-3 times.
I personally also took it easy on my new set for the first 500 miles,
until I inspected & changed the fluid.
If you reuse your old bearings, you prob don’t need to do this run-in.
If you installed new bearings, and your mechanic (or you) did not do this,
then you can cause your diff to overheat, which softens the gear teeth
and bearings making them more prone to breakage.
(I.e. shorter life & more drivetrain HP loss)
I have never heard of a break-in period for a drive shaft.
First, I hope you are enjoying your new gears and increased torque!
Second, this is the first time I have heard of axle bearings going bad on a gear install.
The axle bearing should be unaffected on a gear install,
unless the mechanic was very careless and pulled the axle out too far
or mishandled the axle.
Perhaps he meant to say it was the differential bearings?
New gears should not whine any more then your stock ones did.
Whining gears indicates an incorrect setup.
A slight “whine” usually is not a serious problem (but can be irritating),
Unlike a “load chatter” which could mean chunks of metal are destroying your teeth & bearings!
When installing new gears & especially new bearings
you should go through a run-in procedure to prolong
your gear set & minimize drivetrain loss.
If your mechanic did not tell you to do this run-in,
then he probably did it for you.
The first 2-3 min is usually done under no load, i.e. while it is on the lift.
Then you need to drive at normal speeds for 5-10min, and then let the diff cool down
for ½ hr or more. You need to do this 2-3 times.
I personally also took it easy on my new set for the first 500 miles,
until I inspected & changed the fluid.
If you reuse your old bearings, you prob don’t need to do this run-in.
If you installed new bearings, and your mechanic (or you) did not do this,
then you can cause your diff to overheat, which softens the gear teeth
and bearings making them more prone to breakage.
(I.e. shorter life & more drivetrain HP loss)
I have never heard of a break-in period for a drive shaft.
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