Snoopysvet

I buy some stuff from Ecklers but I know I can find this cheaper,
I can get their rear differential fluid kit, axle fluid, posi additive and gasket for 68.89 + 17.00 for shipping.

Can't I get a gasket, fluid and special sauce from Autozone or Summit Racing?

In addition what kind of rear end do we have in a 1978 Corvette? I want to get the right gasket.

Mako72

I use the Lucas 85-140 gear oil and a bottle of the GM posi additive. I don't have a gasket on the fill plug.

MelWff

the Ecklers kit assumes you are somehow going to remove the back cover to drain the fluid. The majority of people do not do it that way.
You suck the old fluid out with a pump and pour in the gear oil and additive.
Summit Racing should have the gear oil and additive.

Tampa Jerry

You could also go to your local Chevy dealership parts department and purchase the fluid over the counter. Save a few bucks on shipping and get it faster. Jerry

Snoopysvet

Is it best to pull the differential cover off, let that nasty old fluid drain and spray the gears with Berryman B-12 carb cleaner.

Bolt the cover back on with a new gasket then fill the rear end?

As opposed to sucking out the fluid and filling back up?

pws69

10 year "Corvette" forum member and you present this?

Hmmm........

doorgunner

If you have a full day to spare you could remove the cover/drain/clean the bottom of the sump thoroughly/check for metal particles in the old oil.
I wouldn't use carb cleaner on the gear assembly----it would probably get into the bearings and strip all the gear oil off the rollers......

redvetracr

he makes it sound so simple.....

MelWff

Have you actually done any research on how to remove the rear cover?
Have you seen what is all connected to the rear cover?
The cover holds the differential to the cross member.
The spring, camber bracket, etc. attach to the bottom of the cover.

lvmyvt76

there was an article on how to drill the diff on the bottom and tap the hole for a plug while it was still in the car, may of been in "Corvette Fever" magazine a long time ago, anyone done this? it looked very easy if you have the correct tools.

gguillot

I would think it would be easier/cheaper just to invest $70 in a Mityvac fluid evacuator and suck it out the fill hole. That's what I did anyway.

Franks73

Go to your local Chevy dealer, buy GM fluid, and two 4 oz bottles of additive. If you can, drive your a car a bit to warm up the rear fluid. Buy a fluid pump, or a turkey baster, and tubing works. (Takes a while) The fluid really stinks! Careful the tubing doesn't slip off. Gloves and eye protection. Add the fluid until it seeps out of the plug hole. Done.

Snoopysvet

That pesky spare tire cover was in the way, I never noticed that removing the cover was such an ordeal. I think I will just suck it out and refill it.

7T1vette

Process:

1. Break the 'fill' pipe plug loose, then retighten a bit.

2. Drive car for 10 miles (or so) to warm up lube in the diffy.

3. Park in garage and jack rear to get access; remove 'fill' plug.

4. Use syphon [squeeze bulb & plastic tubing] to suck out all the diffy lube possible. (Good 'nuf)

5. Fill diffy with one bottle of rear gear lube; then add the bottle of Posi-Trac additive; top off with some of another bottle of lube [until it begins to run out of 'fill' hole].

6. Install fill plug and tighten to 15 ft-lbs. If you cleaned the threads of all lube, tighten to 20 ft-lbs..

7. DONE! Have a beer! (Didn't cost that much, did it? Forget the Eckler's purchase.)

Ibanez540r

I drilled my diff and installed a drain plug. Fortunately for me, I did it while the diff was out of the car (building the chassis).

The only concern with it being in the car is getting the drill shavings out. I suppose if you flushed the diff real well and let a fair amount of fluid run out the drain hole you'd be OK.

7T1vette

Total waste of time and effort, if you just follow the procedure above. You only change rear-end fluid every 5 years (or so); is that worth risking the integrity of a 'sealed' unit? I don't think so....