Differential drive flange leak.

[gwittman]

I replaced the differential drive flange seal about 2 years ago and it is still working well. However, I have discovered there is a leak coming out of the center of the drive flange where the nut is.

I have studied the Blue Book extensively and can find no reference of a seal for the collar nut area in the drive flange. If I am over looking something please let me know. My plan at the moment is to remove the nut, clean every thing there very well and use a liquid sealant on the collar nut face and first few inner threads. I have used SealAll on the lower bolts of a float bowl of a Holley carburetor with good results. These bolts are wetted with gasoline and if it will seal gasoline, it should seal gear lube.

I have a crush sleeve but plan to just use the nut/flange position marking method and re-tighten to the same position and verify drive torque value.

I am open to any other suggestions.

 

[HB Chris]

There is a large rubber O ring for the side loader cover too but that is all. E12 era diffs use a c-clip inside and no nut so the drive flange can just pop off.

 

[gwittman]

If there is no nut in the E12 era, how does the preload in the pinion bearings get established? We may be talking about two different things. I am talking about the input drive flange that connects to the drive shaft. It looks like I was not clear on that.

 

[Wladek]

Chris probably thought about side cv joints mounts, not about main input.
Corteco seal number for main shaft is on photo below, before full re-assembly clean the surface of main shaft mount internal with fine sand paper or steel wool.

 

[HB Chris]

I read drive flange as output shaft, sorry

 

[gwittman]

Wladek, that seal you are showing is the seal I replace a couple years ago. It is not leaking there. It is leaking through the center where those splines are. This is where the pinion shaft connects to the flange and is held in place with the nut. Somehow the gear lube is getting past the nut, either through the thread or nut face (possibly both).

The flange seal area is totally dry. Gear lube is coming out in the area where the differential flange and driveshaft yoke meet and are bolted together. What you show in replacing the flange seal is basically what I did a couple years ago. It worked very well. Now I must resolve the new leak.

 

[Wladek]

Before putting flange on shaft & bolting it put fair amount of copper grease on teeth. In that place it should do the job as barrier & shouldn't be flushed by oil.

Your inner diff shaft or flange have slightly worn teeth, that's why have some leakage while stress work.

 

[gwittman]

That sounds like good advice. I will take it a step further and put a liquid sealant that hardens on the flat contact surface of the nut and the first few inner threads. That will be a backup in case the grease does not hold the gear lube back.

I don't want to put the sealant on the splines because it makes pretty good adhesive and I may want to remove that flange some day.