Rear End Leak

[NHCharger]

8 3/4" rear end. Just changed the oil before I started any test drives. I ran the car up and down the driveway a few weeks ago, no leaks. Today it got it's first test drive (about 1 1/2 miles). Tonight I notice oil on the garage floor. It's leaking out of the front of the carrier.
I used Royal Purple Synthetic. Still used the additive because I read that the synthetic could be too slippery. I also read a statement on here that if you want your engine to start leaking, just switch to synthetic oil.

Should I switch back to regular oil and see if the leak goes away?

[Cooter]

I've run synthetic oil (Royal Purple) in mine for years and never hadda problem.
How did you change the oil? Did you just add?
If so, the old oil level might notta been up high enough to cause a leak from pinion.

[NHCharger]

Wasn't sure what was in there and for how long. I sucked all the old shit out and filled it up to the bottom of the plug. It didn't leak the first time I tested in the driveway with the new oil

[NHCharger]

Cooter- What weight oil are you using?
Also if I need to change the seal. The rear end is a 489 with 11" drums, not original to the car. I've read through some threads which I cannot find now. There is a crush sleeve behind the yoke. Does this also act as the seal?
Also do I torque it back to spec, 170 lbs. I believe, or see what it's at now and stay with that?

[firefighter3931]

Cooter- What weight oil are you using?
Also if I need to change the seal. The rear end is a 489 with 11" drums, not original to the car. I've read through some threads which I cannot find now. There is a crush sleeve behind the yoke. Does this also act as the seal?
Also do I torque it back to spec, 170 lbs. I believe, or see what it's at now and stay with that?

Brian, i use 85/140 Valvoline gear oil in mine (non-synthetic) 

With the 489 housing it is very important to measure the torque reading before removal of the pinion yoke. The pre-load is set using torque on that crush sleeve and too much or too little torque will alter the preload.

If you don't want to mess with it just install some dino gear oil in it and be done. 


Ron

[Cooter]

Cooter- What weight oil are you using?
Also if I need to change the seal. The rear end is a 489 with 11" drums, not original to the car. I've read through some threads which I cannot find now. There is a crush sleeve behind the yoke. Does this also act as the seal?
Also do I torque it back to spec, 170 lbs. I believe, or see what it's at now and stay with that?

85/140  as well I think it was. Been so long.
if swapping back helps, I'd just go with the easier route.