Diff oil leak

[MSM]

I have recently had my IRS refurbished and having refitted it to the car there is diff oil leakage onto the parking space after a few miles. Investigation shows that the source of the leak is from two openings in the diff casting under the output shaft housings. The attached photo shows the area in question, you are looking up at the bottom of the diff through the opening in the lower cover plate.




The silver feature on centre left is the caliper bracket and the diff drain plug is top right. Roughly half way between the two is a small rusty hole. This apparently is a drain, there is also one on the other side, and these drains are where the leakage is coming from. I am told, by the person who refurbished the IRS, that some diffs have this feature and that the cause of my leakage was too much oil in the diff. the actual level was about 1/2 inch below the filler hole, thus not overfilled and so there must be some other reason for the leakage.

I have never come across this feature before in diffs. Can anyone offer any wise words on how to stop the leakage and the reason for the drain feature originally?

[mgcjag]

Hi Mike......some diffs have these drain holes others dont...depends on diff type/year particularly the o/p shaft housing......the holes are channels that go up to the output shaft housings.....any oil that gets past the output oil seal gets drained away via these holes......on diffs that dont have them the oil gets thrown onto the disc.....so your output seals are leaking......i have just replaced my output shafts/housings with later xjs units recommended and supplied by Alan Slawson (diff builder)....the shaft housing and seal is a better design...Steve

[44DHR]

This previous post may assist.
http://forum.etypeuk.com/viewtopic.php? ... 942#p89942
Output shaft oil seal is leaking.
Regards,
Dave

[Heuer]

Check the breather on the top of the diff has not been blocked. Pressure builds as the oil gets hot and it gets forced out.

[MSM]

Thank you Steve and Dave, looks like that is the cause of the problem.

Thank you David, I have checked the breather and it is clear, it would appear to be the bearing housing as above.

[MSM]

It is always nice to be able to conclude a question with a positive answer.

After much discussion and investigation it was decided to deliver the car to the company that refurbished the IRS and get them to investigate and cure the problem. This was done recently and they reported that they had fitted the correct output shaft oil seals as shown in 'the book' but the seals actually needed to be 1/4 inch longer to prevent oil leakage out of the drains. This longer seal is apparently fitted to later diffs and has now been fitted.

I am pleased to be able to report that the oil leakage has stopped.

Even though I can understand that fitting a longer oil seal will cure the problem there are some aspects of the oil sealing arrangements in this area which are still a mystery to me, particularly the O ring at the inboard end of the bearings. Search as I might I have not been able to find a sectional view of this area, only exploded views. Does anyone have a sectional view to share to aid understanding?

[mgcjag]

Hi Mike.....i am very scheptical of what you have been told re the longer oil seal......would be great to know what the part number actually is......look at the oil seal and see how it buts up to the tiny lip on the bearing and how you shim the carrier...I actually replaced the complete o/p shaft/bearing carrier for the later style from an xjs as reccomended by Alan Slawson (diff rebuilder) ....your diff is i think due to the drain holes the style as mine and ofter refered to as type 3 The same o/p shaft arrangement was used in the S3 E type so full details can be found in in a S3 service manual (see knowledge base) a few photoes here showing cross section and fitting instructions....Steve

[MSM]

Steve

Thank you for that, very helpful. I'll print out a copy and study it at my leisure.