Re: 742 to 489 and 741

[Derrick Brown <63max426@xxxxxxxxx>]

Hi Don,

Thanks.
Can you still get rebuild kits for the clutch style suregrip?  if so  
who is a good source>?
same for the 742 assembly itself, ie............bearings , seals  
etc........is there a preferred source?

thanks again,

On Nov 16, 2007, at 11:34 AM, Don Dulmage wrote:

> All have the same size shaft at the spline. The 742 is 1 3/4 at the  
> rear of the pinion by the gear end and the 489 is 1 7/8 the X or  
> 741 is 1 3/8. HOWEVER!!!! (big word aint it. ) they are all the  
> same size where the spline attaches (nut or threaded end of the  
> pinion) and since no piece is stronger than its weakest part the  
> idea that  a 741 or 742 is too weak for serious street use does not  
> wash. The bigger bearing inside increases load carrying abilty by  
> the gear  but in practice the smaller bearing , the front pinion  
> bearing is the one that will fail if you do have any trouble. and  
> it is realitively similar in all three diffs.
> Limited slips (cone and clutch can often be swapped without  
> trouble. Sometimes the carrier bearings are different but with the  
> matching races will fit nicely. I have done this many many times  
> over the years. Axle adjustment or shimming can be tricky sometimes  
> however a green bearing kit makes this detail moot.
> Don
> PS there are two splines often seen in all diffs , at least all 742  
> and 489s) fine spline and course splines. Often the front seal is  
> the same number as well BTW regardless of the case number
> Author of
> Return to Deutschland (True Adventure)
> Old Reliable (Mopar)
> http://altonapublicschool.faithweb.com/
>
> http://seniordragster.bravehost.com/index.html
> [Non-text portions of this message have been removed]

Derrick Brown
'63 Sport Fury, 4 speed
derrickb@xxxxxxx