How to loosen clutches in the rear end of a 65 coupe

[John S.]

I have put the rear end lubrication in and done figure eights until I am blue in the face. Does any one have any suggestions how to free them up besides tearing apart the rear end.

[Richard G.]

Re: How to loosen clutches in the rear end of a 65 coupe

Any more history you can add?
How long has it been this way?
When was it worked on last.
If it was repaired what was done?
Etc.

[John S.]

Re: How to loosen clutches in the rear end of a 65 coupe

The car has set for about 20 years. I have no actual history but to my knowledge no work was done on the rear end.

[Dan H.]

Re: How to loosen clutches in the rear end of a 65 coupe

John, I also put lots of miles and figure eights on my 64, still chattered. It had two additives tubes in it, no help. Finally had the rear end drained, put GM synthetic gear lube and two tubes of friction additive, smooth as can be now. Moral to story, ALWAYS use the synthetic gear lube.
Dan

[Duke W.]

Re: How to loosen clutches in the rear end of a 65 coupe

I don't understand what you think the problem is. Positraction has a preload to the clutches, and it should take something around 45 lb-ft to break them loose.

Jack up one rear corner, DOUBLE CHOCK the diagonal front wheel. Apply torque to a wheel nut. A beam type torque wrench is best so you can easily read breakaway torque. If you have a ratchet type start at about 25-30 lb-ft and increase in five lb-ft increments until breakaway.

If the breakaway torque is less than25-30 then the Positraction is worn to about the service limit.

Duke

[Edward J.]

Re: How to loosen clutches in the rear end of a 65 coupe

I have put the rear end lubrication in and done figure eights until I am blue in the face. Does any one have any suggestions how to free them up besides tearing apart the rear end.

20 years is a long time to let something sit, if there was the possiblity that there was some mositure in the fluid the clutches maybe sticking together because of rust on the surfaces. If the fluid looks milky then if maybe time for a rebuild.

[Joseph T.]

Re: How to loosen clutches in the rear end of a 65 coupe

I have sucked out the rear end lube and filled it with marvel mystery oil and done many figure 8 s. Then sucked out the marvel mystery oil and filled it with rear end lube and the GM additive. Did the trick.

[Gary R.]

Re: How to loosen clutches in the rear end of a 65 coupe

That would be worth a try the MM might loosen them up. There is not a lot of movement in them to begin with so I would try this and if not then the posi needs to be setup. The clutches don't wear as much as you would think. Mic up a used set and new set and you might find they are close. The deal is the setup of the clutches and how balanced they are between L & R.

[Frank D.]

Re: How to loosen clutches in the rear end of a 65 coupe

Gary - are you back in business and setup now for this type of work ??
I know you were moving or something...

[Gary R.]

Re: How to loosen clutches in the rear end of a 65 coupe

Frank I setup shop at home now and like it a lot better. I am building a 66 diff now in fact, the posi is going on my machine today for a run in.