Rear differential

[greenfield]

Apparently, I had a fluid leak in the rear differnetial while driving. Became keenly aware of the situation while driving as smoke was coming from the rear of the car. Stopped and found fluid burning on outside of rear differential cover. Towed the car back to a mechanic and now wondering how far to go with repairs.

Starting with the differential; new, used or rebuilt?
Right & Left rear axle's?
Drive shaft to the gear box?
Seals - almost certainly...

What would be a "fair" price for parts and replacement of each item?
Prices so far are ~ $600 for the gear box .. 100/ea for axles ... misc seals, unknown.

Stuck in limbo,
Phil

[freakray]

Phil,

Let's start with addressing what model car you have, there was a recall on the rear differential seals on certain models as they could develop a grease leak over time.
One of the signs of this grease leak was the oil burning on the outside of the differential due to the exhaust heat like you described.

Second, please tell me you didn't actually tow an AWD Subaru, as in 2 wheels on the ground and 2 wheels lifted.
If you did, you just did irrepairable damage to the drivetrain and this is most likely why the mechanic is finding so much requiring replacement at the rear.

[greenfield]

The car was placed on a flatbed and transported. Tow was the wrong selection of words except to say, it wasn't driven the rest of the way home.

The news so far is;
$600-800 for a new differential
~ 300/ea for new axles
~ 50/ea for bushings
~ 400 for labor

confusing issue on axles
- Subaru doesn't think it will need them
- Meinike says 360 for right & 240 for left ?!
- local garage says 110 ea regardless of side

What if anything can I do or gain by the recall issue?

[2turboimports]

that's waaay too much to be paying for a new diffrential. even paying 300/ea for axles is robbery.

did you take this to a shop or a dealer?

[greenfield]

Checked 3 places ; a local dealer, Meinike, and Subaru.
~ 500-600 for diff
~ 150/ea for axles
2 yr .. 24k warranty at Subaru, 3 months at local dealer ...

[Moppie]

If the rear seals in the diff have failed and its lost enough oil to do damage then only the diff itself needs replacing or rebuilding.

The axles will be perfectly OK, and unless the mechanic can show you some pyhsical damage to them then I suggest you take the car somewhere else as he is trying to rip you off.


But before replacing the diff you need to know if it is actualy damaged.
It only takes a very very small amount of oil to smoke off an exhaust, but it takes a very large amount of oil to leak out before damage will occur.
The diff should hold about 1-2 litres (half a gallon?) and will run ok under normaly driving conditions with half its normal amount.
If over a litre of oil had leaked out there would be plenty of visable signs.
A large, and I mean large stain under the back of the car where it was parked.
Oil stains all over the underside of the car, and the whole diff and everything behind it would be liberaly coated in oil.
Smoking off the exhaust would be excessive, and would have been ongoing for some time.

And then if the oil level had dropped enough to do any damage you would hear the bearings begin to sieze up.
Having experianced several badly worn diffs failing while driving the noise is extreme. As the oil level reachs a level where it can no longer lubricate the bearings and gear teeth they over heat and begin to wear against each other.
The result is a very loud screaching squealing noise, and or, a deep rumble and that horriable sound of metal grinding on metal.
If the car is driven long enough something will eventualy break or seize, meaning either loss of drive or locking of the diff.


If the only thing you experianced was a little smoke, and some oil dripping off the underside of the diff then it sounds like you caught it well before any damage was done.
If the diff is still in the car, and hasnt been drained then you will be able to check the oil level.
If its still above half then just get the faulty seals replaced as you have nothing else to worry about.
If the oil level is very low, or the diff has been drained and only a very small amount of burnt smelling oil has come out then its a good idea to pull the diff apart and check for wear on the bearing surfaces and gear teeth.
Then you need only replace the bits that need it, or deciede of a new or used diff is a better idea.


The only reason I can think your mechanic wants to replace the axles is if one or both has worn CV joints, which would have been conincidently discovered when the diff was being looked at.
Its also possible oil leaking from the diff may have deteriorated one of the CV boots, but at $10 each and on hours labour the priced you have been quoted are excessive for thier replacement.