Juliet

Believe it or not, I did clean up this once before - about 8k miles ago. What's the likely source of the leak and how does one fix it? It's dripped down onto the exhaust and run forward even. Can you tell anything from this before picture? Thanks, ~Juliet

PRNDL

I'm a little lost. Is that the tag that says, "Use positraction additive" or something like that? hint hint.... :) MJ

yellow 72

My filler plug "weeps" a little gear lube. It appears that may be where your's is leaking.
I would spray clean it with some brake cleaner or the like and watch it closely to detect just where it's coming from.

paso

Well the plastic breather pipe is NOT on that side so unless it is running across the top and running down the right side I would suspect it could be a small crack or where the back bolt goes into the diff cover the oil could be leaking past the threads. The back bolts I believe go directly into the inside of the diff cover. I can check tomorrow as I have a diff cover in the shop. My 77 cover had a small casting flaw and it wept oil out But your's look like it is too much oil for that to be the cause.

Juliet

Ha Ha. Rear Diff Mark. ;) Does this help?

Juliet

Thanks. Greg took a quick look at it and didn't think it was from the plug either. :( I'll clean it up and see if I can spot something - but will I have to drive it to get it to ooze again? How much work is it to remove it while I have all the other suspension out of the car? ~Juliet

bence13_33

Juliet:
IMO here is what I would do. Some WD40 and some scrubbing will clean that mess right up. One way to solve the leak would be to take the filler plug out and put a light coat of black RTV on the threads and screw it back in. The black RTV is oil resistant so it should keep the rear end lube where it's supposed to be (in the rear end). Hope I helped :cheers:.

topless68

Juliet,

I have a question for you. Step back and look at the big picture for a sec.

Number 1, you know it's gear lube.

Number 2, you know it's coming from the differential.

So unless your plug is walking out on the job, it's coming from either your front yoke or your side yokes. In either case, you need to pull the diff to change 'em. :(
From my limited experience, usually if the front yoke or gasket is leaking, you'll get a drip on your driveway. I would suspect the side yokes, in which you have to pull the cover, which means you have to drop the diff. No, it's not bad to do...$2 and a whole lot of labor. :cheers:

killain

Juliet, I going to venture that you have a leak in the gasket between the casing(The Pumpkin) and the rear end cover. (the thingie that holds the spring) Yep, I think that's were you slight oil leak is originating from. I'd try tightening the rear end cover bolts first! Make sure you top off the rear oil as well. :seeya

Juliet

OK - nomenclature time here please. :) So the possible leak points are plug, front yoke, side yoke or seal between pumpkin and back part? So, are the side yokes the same thing as the seal or are those different things? Just what does yoke mean? :crazy: I haven't put my head around to the front of this thing yet to see what's there. :eek: So the driveshaft has to come off to get it out huh? So is the front yoke somethign where the driveshaft attaches to? Thanks, ~Juliet

454Big

Juliet,

check out the seal of the turning part that is in front of the plug (the so called yoke:D)
To me it looks like this has become brittle.
An axle drop is involved in this!

As a first measure check the fluid level in the diff.
Should be even with the plug hole.
Replace and recheck after 1000 miles or so. Just to become an idea how urgent the problem is.......

A diff drop performed by a shop should not be cheap, unfortunately.
When you have an idea of how fast this mess is, you might be able to plan your budget and to rebuild the diff when it fits the budget!

Larry B.

Hi juliet... There is most likely a small crack as that is a common thing on those. That is actually the cover. Sometimes the mounting ears break too. Something about 30 year old castings! :)

Dalannex

Ooze in rear huh? Sounds like some Pepto-Bismol is in order. ;) :yesnod:

Yokes are the part that turns and have u-joints in them. The front on has the driveshaft hooked on it, the side ones have axle shafts hooked on them. I tend to think you should clean it up with some Orange Clean to get the grease off, then check it over real good to see if there is a crack in the cover. If not, there's about a 90% chance it's a seal around a yoke. The yokes just have rubber seals around them that put pressure on the shaft of the yoke and seal the oil in. They get pretty brittle after a few years. And, as we all know Sophia is no spring chicken anymore. :D Well, there. I typed and typed and didn't say anything you don't already know.

Justin

Rocket Ron

At first I thought it was a personal problem.
I would go simple first. Clean up, check fluid level, then use a little teflon on the threads on the plug. If you haven't already.
Good luck.

GTR1999

Hi Juliet,
As the others have suggested, it can only be from a limited number of sources. Looking at your picture I wonder if the plug was tight or just snug up against the red label? As stated this is a pipe plug, which I'm sure you know is tapered to tighten up. Try a little teflon tape after cleaning it up and see if you still have a problem. If you're going to go through the rear suspension anyway then you might want to drop it out. I'm sure with the experience you and Greg have it won't pose a problem. Once out do what I'm doing now- change the seals,bearings, and gasket. I'm also installing a Muskegon HD cover. It's not a bad job and the housing will mount on an engine stand by using 2 of the 4 strut rod bracket holes. All you need are a couple of gr 8 3/8-16x4" bolts from Home Depot. I have a picture I could send you if you want. If you change the pinion seal put a little Permatex #2 on the spline of the pinion so it doesn't weep out.
Gary


[Modified by gtr1999, 8:09 AM 1/27/2002]

killain

Juliet,
The yokes are the two 'Y' things that come out of each side and drive the two shafts that go to each wheel. The pinion is the piece that goes in the front of the differintial and the driveshaft hooks to it, (kinda like the yokes, but there is only one) The differential case is the main large case that holds all the other parts, (also called the pumpkin or differential) and the cover is the part in back that holds the spring and is bolted to to the frame at the top. Inbetween the cover and the differential itseft is a very thin gasket and the two parts are held together with ten bolds around the edge. I would check these bolts to see if any are loose. From the pictures I don't think the pinion is leaking, but the rear often developes a leak at the rear cover, (It also happens a lot on regular full size GM vehicles as well) This is a poor design and often leaks develope here. On a C-3 corvette, this rear end cover does double duty as it also holds the rear spring and is bolted to the rear frame crossmember, so it has plenty of stress on it. Whatever you do make sure you replenish the oil in the rear. It's a small thing but often people forget to do this and the rear runs hotter without the proper amount of oil and limited slip additive. :eek: