After checking the rear fluid level, I filled it back up to the proper level and then found out where the gear oil went. To help out with some interior work, I left the rear stands in place. The angle put the fluid up against the rear's front seal and now its all over the floor. Working on the floor, I don't see how I can replace the seal without removing the rear.

 

This rear does need to come out to replace the front seal, correct?

 

You can easily replace the front seal without removing the 3rd member (an old term for rear ends). Just remove the drive shaft and use a 3/4" impact wrench to buzz the yoke nut off. Pull the yoke off, bang the seal out and bang another one in, and re-install the yoke and drive shaft. The trick is having the rear end high enough for you to do the job.

 

That's the big trick, I am like 6'1" with no lift in my garage.

 

You'll have to mark the nut-to-housing with paint or some method, there is a specific pre-load the nut is adjusted to. Just slamming the nut back on won't do. You probably want to count exposed threads before removal and match that upon re-install. It should be close enough to work. Happy motoring!

 

With the front of the differential bolted to that rear cross member, will I be able to see any of that? I really can't even see the bolts that hold the rear driveshaft joint in place. It's all pretty well hidden on this 80. There is no space to work, I will need to reach in over the top of the cross member to access the yoke. This is a Dana rear, I am not an expert on corvette rears, but I think this is probably a shimmed yoke, no crush washer. Will the new seal have a flange and bottom out or will it have to be seat to a given depth. To me, it looks easier to pull the diff to do the job correctly the first time around.

 

Check this thread: http://www.google.com/url?sa=t&rct=j...id9_F6n49ODAyQ

 

Yes, thank you. I finally did come across that one and as usual, tracdoogg had a good solution.

 

Hello fellow C3 fans. I too need to replace the front seal on my 73 differential. If I am reading this thread correctly, I might be able to replace the front seal without removing the differential? Thanks for any input.

 

The seal on a 1980 is very difficult to get to in the car and to do it to the level of accuracy required, the space is incredible limited. The 80 has shims and not a crush seal according to a couple of excellent sources. Either way, it has to go back to spec's. If you can get to it on a 73, then it would be possible, you just need to reinstall to the same spec before pulling the yoke. Somebody out on the forum must know if it can be done in the car on a 73 without pulling the diff.

 

The rear diff should be a Dana Spicer 44ICS with came out I think In 1980.They were in 81&82 I have done a couple of these. The front mount is cast into the housing with makes it all most impossible to do in the car. I drop the diff down so I can get at the u joint bolts. if the front seal is leaking I would tear it out and put new seals on the whole unit. As I recall they are solid pinion spacers.

Hopes this helps

 

Anything is possible. The question is whether or not is it feasible.
Chuck: no spacer behind the bearing, just shims. Everything else you said is 100% correct.
BlackC3: Did you get your seal changed?
On the 80-82 Dana diffs, it depends what seal you use also. If you use the correct National seal you cannot just tap it in. It is a reverse design so it will look like it is in backwards. If you use the C/R seal it installs like any other but must be fully seated in the bore, not just flush with the housing.
63-79 iron diffs: They use as special seal that you cannot buy. Even from the dealer. They say they have the correct seal but it is not. The seal you get, from the dealer or anywhere else, is a 12 bolt seal which has a much thicker body. It does not seat flush against the housing but sits above it about 1/8-1/4 in. Inside the housing is a very small step that the seal bottoms on. If you hit the seal too hard it can ride up over the step and the seal will not be square to the body or perpendicular to the pinion. This is why I never recommend changing the seal in the car.
Motive Gear sells bearing kits that sometimes has the correct pinion seal. It is very random and I have tried to purchase the seal separately with no luck. One question I always have is why was the seal leaking the first place? It is possible and very common the seal is just worn out.
The pinion flange, in almost all cases, is a press fit. Usually requires hitting it with a hammer and punch to remove it. Marking the nut, pinion, and flange is your best hope of getting the nut torqued close to original position but is a hope and prayer at best. The correct way in a vette is to remove the halfshafts first, take a preload reading before removing the flange, and take a reading after assembly. But this adds hours to the job and takes less time to just pull the diff.
There have been countless threads about stub axle wear. So while the diff is on the bench this is a good time to pull the cover and inspect everything. There is much more to check than just the stub axles. Cross shaft wear, cross shaft bore wear, cracked carriers, cracked or broken preload springs and plates, and if you have a 76, 78, or 79 ring gear bolt torque. But it's a good idea to check all the bolts on all years. Worst case, if everything checks fine, you're out 20$ for new side seals and a cover gasket. And while it's out you can change the front mount cushions.
Mike

 

Actually, no.

The vettes all jacked up on stands and ready for disassembly, but medical problems put me on hold . The 30" of snow last weekend didn't help either.

I just know I am going to get this thing out and up on the bench and then want to change out the 3.07 that's in it to a 3.50 (or 3.55?) As a matter of fact I was just talking with Brian at S&K Speed (Tranny Shop) about who does diff's here on Long Island and it's a really short list.

 

Are the ring gear bolts reverse thread?

 

Nope, standard 3/8 x 24. rh.
Mike

 

Pay attention what Mike says..

We had a customer that purchased and tried to install three before bringing us the car. He installed it backwards.. do that and they will leak for sure.

I will say that it is possible to install the 80-82 seal without pulling the rear end on a lift....Easy no! But do-able.

Doing it on the floor would be impossible IMHO.

Willcox

 

Back on track with removing the diff out of the 80. I wanted to get some basic parts before I get it up on the bench. From the list of manufactures, SKF, National, Timken, Napa, etc.. could you be so kind as to list your preference brand for the pinion and side yoke seals? Part numbers? Also, this vette only has about 52k on it but is there a chance it might need a redi-sleeve for the pinion yoke?