124 Diff (rear axle) - Leaking Input Flange Fitting

[ITA124]

G'day All,

Before I start. Aussie's call the rear axle a "Diff" as in differential.

Have removed the diff to look at a number of things, It's easier than working under the car. Anyway, the diff was leaking at the mating face where the drive shaft bolts to the diff. Suspecting a worn seal, discovered that the leak was not from the seal, but along the spline, around the washer that is held in place by the nut and out between this mating face.

What I want to know is how do I seal oil running along the spline to the mounting washer and nut.

The nut was tight and the washer looks quite smooth (cannot see leak path)

Here are a few photos.

Manufactured a removal tool. Copy of A.70345. Half hour side job that save much time.



The mounting side is 'oily'. Evident of a leak here. Plus the small puddle on the ground.



The oil seal side is dry, albeit dirty. No oil leaking past the seal



How do I seal the face between the washer and the drive flange?



Schematic for your reference

[manoa matt]

You'll notice the oil seal rides on the back face of the driveshaft flanged fitting, the splined interface between the flanged fitting and the pinion are internal to the oil cavity. Oil will make its way past the splines through centrifugal force, past the washer/nut and into the area between the two bolted flanges eventually leaking out at the joint.

The sure way to prevent excessive oil weeping at that area is to install a new oil seal, clean all parts and splines with brake parts cleaner, apply RTV sealant to the splined interface, assemble, and install RTV sealant, or a paper gasket at the interface between the two flanges that are held together with four bolts.