Dif Oil

[Aldwyn]

My dif's leak is getting worse and worse. I really need to put her up on jacks and find out where it's leaking! (looking under the car, it doesn't seem to be coming from the cover... more like it's coming from where the drive shaft meets the dif. (there appears to be oil all over the drive shaft)

Anyway, on to my question!

How the heck do I put more oil in the dif? I am afraid I will get low or run dry and start causing damage to the dif.

Bentley's only seems to show how to adjust levels by opening the drain screw, but not how to refill.

Any help would be appreciated!

Thanks!
Aldwyn

 

[tdskip]

Double check, but the differential is refilled by pumping oil into the opening where the drain plug goes.

You'll need a hand pump to do it. Make sure to not overfill it, and it it full when oil starts to weep out of the drain plug hole.

Wipe everything down to make sure it clean before removing the drain plug hole.

 

[Twosheds]

You can get diff oil in quart plastic containers with a pump on them at Pep Boys or the like. The clear tube goes into the fill plug opening and you just pump the handle until oil flows out around the fill opening and onto the floor.

I forget the oil brand, but it doesn't matter if it's just going to leak out anyway!

 

[guzzul]

As tdskip says, you will need to pump it in through the plug on the upper LH side of the diff, same as where you check the oil level. The older difs used to have a drain plug in the bottom as well as the fill plug, but later models have only one plug through which you drain, fill and check.

Sounds like your front pinion seal might be leaking. You can replace this without removing the dif if you have enough working room under the vehicle. If that's what you need to do, you will need to suck all the remaining diff oil back out however, through that same hole.

 

[Andrew Mace]

...Sounds like your front pinion seal might be leaking....

Agreed, but it's also possible that the vent is simply plugged. It's nothing more than a cotter pin that moves up and down in a hole in the upper right part of the rear cover. It can get plugged with road grime and such, which can lead to leaks elsewhere.

Worth a quick check!

 

[Aldwyn]

Thanks gents! Trying to work out some lift time with my LBG neighbor for this week... so if he has time for me, I'll be able to put her up and see what's going on.

Thanks for the info, though! Hopefully it's as easy as cleaning the vent mentioned!

 

[Andrew Mace]

...Hopefully it's as easy as cleaning the vent mentioned!

No guarantee that will do it, although it worked wonders on my Herald! I'll keep my fingers crossed, though....

 

[RobT]

BTW you need to use GL4 transmission oil. The more common GL5 has too much sulfur that will eat the brass shims in the diff. TRF and others sell the GL4.

Rob.

 

[Aldwyn]

Thanks Rob! Will look out for GL4...