Leak in front of rear differential where it coupled to driveshaft.

[StckweldinSteve]

Moved the car and there’s a small puddle. Got under and saw this leaking.

 

[R413]

Pinion seal is bad.

since you didn’t know what it is then you probably can‘t change it. Kind of tricky to do, yoke nut is tightened to 250 ft lbs.

 

[#41]

Hard to believe it has not been leaking for years considering how crusted the axle is. FYI - This is a common issue and does not necessarily need to be repaired immediately. You can get by for quite a long time using a drip pan and checking and keeping the diff fluid topped off.

 

[AR67GTX]

If you can get the case numbers off it (ending in 741, 742 or 489 most likely) then we can be tell you if it’s something you can possibly tackle with some tools (big spanner wrench and torque wrench that reads up to 250 ft lbs) or if it’s something best to leave alone for now.

 

[ckessel]

Not an 8.75 there, looks like a 8.25 with that cover. Different critter but same procedure. Seal will be different too.

 

[StckweldinSteve]

If you can get the case numbers off it (ending in 741, 742 or 489 most likely) then we can be tell you if it’s something you can possibly tackle with some tools (big spanner wrench and torque wrench that reads up to 250 ft lbs) or if it’s something best to leave alone for now.

I’m going to wire brush/clean everything under the rear of the car and paint it while I have the gas tank out I’ll get those numbers if they can be read. Thanks.

 

[StckweldinSteve]

Hard to believe it has not been leaking for years considering how crusted the axle is. FYI - This is a common issue and does not necessarily need to be repaired immediately. You can get by for quite a long time using a drip pan and checking and keeping the diff fluid topped off.

I’ll probably limp it by for now with topping it off. I dropped the gas tank today since I’m about to start welding in my floor patches. Going to have to replace that tank also. Rust inside and some bubbling rust outside. While I have that dropped I’m going to clean/ wire brush and paint everything under there. I haven’t had the car a very long time, it’s a 74 satellite. It probably has been leaking a while and I didn’t notice it at first.

 

[451Mopar]

Looks like the pinion seal. If/when replacing, check the seal surface of the yoke for wear. There are repair sleeves that can be pressed onto the yoke if it is worn.
A little sealer on the yoke splines too.
Ratech yoke holder & puller tool:
Ratech 18002 Ratech Combination Pinion Yoke Holder and Puller Tools | Summit Racing
Yoke repair sleeve (8-3/4" & Dana 60) Not sure if this works with your axle size?
8 3/4" or Dana 60 Pinion Yoke Repair Sleeve