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tennessee mopar nut
04-06-2008, 11:01 PM
I had recently built an 8 3/4 rearend with new gears and a suregrip. the stump came out of a 62-4 imperial with a 2.76 suregrip. 742 casting.
Upon dissasembly i noticed there was no crush sleeve. cuz thats all i seem to hear about "crush sleeve this or that" So i called hensley performance, and they really had no answer to my question either. so i put the thing back together with the new gears, bearings, and shims per instuctions. got a nice contact patch and everything. rebuilt the entire housing and brakes too.
So now im doin the same for my buddys 66 coronet. using an open stump from a 69 satellite. 741 casting. now this one has a solid spacer with shims between the pinon bearings. WHATS UP WITH THAT?
Is my 742 casting gonna shred? is it supposed to have this mystery "crush sleeve"? or one of the affore mentioned solid sleeve? I have not yet driven the car yet
Throw some knowledge at me please:whack:
thanks TMnut

ehostler
04-07-2008, 12:07 AM
From http://www.autohobbydigest.com/8_75.html

1-3/8" small stem pinion... (aka. '741')...
Carrier casting numbers: 1820657 (1957-1964), 2070741 (1963-1972). This assembly was typically used in low weight/low horsepower applications through low weight/medium horsepower and high weight/low horsepower applications. Pinion depth and bearing preload is set with shims. Differential bearing setting (ie. backlash ) is set with threaded adjusters.

1-3/4" large stem pinion... (aka. '742')...
Carrier casting numbers: 1634985 (1957-1964), 2070742 (~1961-1969). This assembly was replaced by a phase-in of the 1-7/8" pinion starting in the 1969 model year. 1970 RW (Plymouth and Dodge mid-size) were the last models to use the 1-3/4" which appeared in a 2881489 case. This assembly was typically used in high weight/medium horsepower applications through high weight/high horsepower applications. Pinion depth and bearing preload is set with shims. Differential bearing setting (ie. backlash ) is set with threaded adjusters.

1-7/8" tapered stem pinion... (aka. '489')...
Carrier casting numbers: 2881488, 2881489 (1969-1974). This assembly was introduced in 1969 and was phased-in as a replacement for both the 1-3/4" "742" unit and the 1-3/8" "741" unit. Note: the 1-3/4" pinion also appeared in some '489' carriers during this period. By 1973, the '489' was the only unit available in passenger car applications. This assembly was typically used in high weight/medium horsepower applications through high weight/high horsepower applications. Pinion depth is set with shims, preload is set with a crush sleeve. Differential bearing setting (ie. backlash ) is set with threaded adjusters.

dave5711
04-07-2008, 01:12 AM
Ed is bang on. No crush sleeve in a 742

742 uses shims to set the pinion bearing preload.

The question is, if you've put yours back together, what was the preload at?

did you check the rotating torque, as specified in the manual? IIRC Should be around 20 to 40 inch pounds with new bearings. xloser to 20 if used bearings.

I will say that if you have no idea what the pinion preload was/is, then the chances for a failure are quite good.

John Kunkel
04-07-2008, 04:26 PM
"pinion bearing preload is set with a crush sleeve."

You see this statement a lot in regard to rear ends but it's not quite true; the preload is "set" by how much the yoke nut is tightened, the crush sleeve merely maintains pressure to keep the nut tight.

If there were another positive means of keeping the nut tight, the crush sleeve could be left out.

rusty duster
04-08-2008, 05:30 PM
you tighten down on the crush collar until you reach the pre-load measurement;which I don't know the amount.The crush sleeve can not be left out unless you replace the crush sleeve with a spacer and shims;which is a better fix.

dave5711
04-09-2008, 12:57 AM
you tighten down on the crush collar until you reach the pre-load measurement;which I don't know the amount.The crush sleeve can not be left out unless you replace the crush sleeve with a spacer and shims;which is a better fix..


That's a great explanation, BUT there are differential designs that don't have a crush sleeve, and never did from the factory.

As mentioned above, the mopar 742 case is one of them.
It uses shims between the end of the pinion gear, and the bearing. There is no place to put a crush sleeve in this design,

Dana 60(and the bigger dana's) is the same. No crush sleeve

On these designs you tighten the pinion nut to the torque spec, and verify the rotating torque of the pinion gear.(check continually while tightening incasae you are way too shy on shims, and you'll destroy the bearings)

if the rotating torque is too high, you need more shim.
If it's too low, you need less.

The shims, or a crush sleeve, all acomplish the same thing. They hold the pinion bearings apart, while the nut holds them together.

5th Ave Sleeper
04-09-2008, 07:30 AM
Ok this settles my mind somwhat. because i did use an inch pound wrench on the pinon nut. I did use new bearings as well. so i feel better now. thank to all!
Oh by the way TN mopar nut is now me