Help with U-joint Area leak

[Bottomlesspit]

I have worked on just about every part of a mustang, but always left the pinion and diffy alone. I did install my aluminum driveshaft however
We have my son's 92 up on jackstands in the garage trying to get it roadworthy. It sat there for a few days and not a drip of liquid under it at all. All of a sudden, 2 days ago there was a small puddle of oil under the rearend. I wiped it up. Next day another puddle of oil...and so on.
I got under and checked it all out, thinking I must have a leaking differential. I wiped it all down well and watched.
Not knowing the parts all that well, here is what I see.
The front of the pumpkin appears dry.
There seems to be oil coming out from the u joints. I see there is a rubber looking bushing on the diffy side of the u joints. I moved the driveshaft around a bit and noticed that when pressure changes against the rubber bushings inside the u joints it gets wet around the bushing.
Does any of this make sense? I could possibly post a picture tomorrow evening if not.
Where or how would oil (I assume gear oil) get to this bushing? I don't remember any oil or parts with oil when I put the aluminum driveshaft into my old 93 surge demon vert. Again, I looked closely where the yoke comes out of the pumpkin and it "appears" dry.
I hope someone can help me out here. We have to get this car out of the garage soon. Poor kid hasn't driven it since we bought it!
Looks like the new Harmonic balancer goes in tomorrow~
Thanks,
Ken

 

[BLOWN 5.0 FOX]

Sounds to me like a blown pinion seal. Always a good excuse to build the rear end up with some gears!!

 

[Bottomlesspit]

Yeah, I did some digging around in the Haynes and Chilton's manuals and that is probably the problem. I was worried it would require going in from the backside of the pumpkin and I really didn't want to mess around inside there. From what I gather it seems that the seal is worked from the driveshaft side of things, which might make it a bit easier for us.
The car already has 3.73 gears so I want to leave all that alone. A rear girdle wouldn't be that bad though???? I do know that the differential has to be out of oil by now...its all on our garage floor!
Thanks for the reply.
Ken

 

[HISSIN50]

The pinion seal was my first thought too. Ken, did you happen to notice any oil whipped onto the underbody (above the rear end)? With a leaking pinion seal, often the fluid whips off the rotating assembly and splatters around, making a gooey mess.

I am not sure if you are asking about a girdle..?? I have not used one on a stang (or 8.8") but I like them. Do note that it appears that some self-clearance the spare tire well (as 89Mustang GX puts it).

Good luck Ken.

 

[Bottomlesspit]

Hissin50,
Matter of fact, there is a gross looking mess all around that area. It looks to be fairly thick, and extremely goooey! I bet you guys are right then. I just hope replacing this seal is not too hard to do. We have enough projects now that it seems the car will be totally rebuilt before it hits the road. This was just supposed to be a cheap, get around town, first car for my son. I figured we could work on it together and teach him what I know about these cars. Darn if as soon as we got it home and started really looking it over that we found that the whole thing had been hacked, sacked, chopped, and stuck together in somebody's back alley somewhere. Just last night I had to replace the STOCK 92 rear shocks, and while under there noticed there were only 2 bolts holding on the whole rear fender assembly, the lower control arm bolt didn't have a nut on it, the balancer had thrown its rubber insides, the electric fan was probably 3 sizes too small to cool the engine, .....the list is 10 times longer than this, but I digress.
Won't let mom go out again and look at stangs with our kids!!! Oh well, we are having "fun"!!!
Any info about replacing this rear pinion seal is appreciated.
Ken

 

[HISSIN50]

Ken, I have not done a pinion seal on an 8.8" yet (I need to one on the '88 actually).
So I cant offer anything more than what you know.

I read up on it once and it seems to me:

Remove the pinion nut (locking the driveline helps via the E-brake, etc).

Remove the yoke - it might fight you.

Then remove the seal with your choice of methodology. Then replace in reverse order of removal (this last line was my attempt to sound like a repair manual. LOL). A seal driver or sockets/pipe, etc might be a good idea for driving the seal in.

You probably already know way more than that, but that is what I recall. It was one of those things that did not sound bad, until one thing goes wrong and hangs you up for a day (that is how things go for me). I am sure others will chime in with really good info.

It sounds like a typical mustang project. You will look back at it with fond memories (probably not, but that sounds poetic).

Good luck bud.