8 3/4 741 or 489 case are they interchangeable ?

[trapster]

I don't know the difference between the 2 cases but I know I have swapped the 2 out before.

I have a 2.76 single 741 case in the car now
and a not so limited slip 489 case with 3.55's in it sitting on the bench.

I am going to send the 489 to Dr. Diff to rebuild and then put it in the car.

Are they interchangeable and what is the difference ?

thanks for the help.

David

 

[Guitar Jones]

Pinion sizes are different as is the way the pinion bearing preload is set. If you swap them complete they are interchangable. Not all the individual parts are though.

 

[1qwikScamp]

the carrier in them is the same just the ring and pinion is difrent

 

[trapster]

Cool, thanks

I was worried that one of them was shorter than the other.

I don't plan on swapping parts between the cases.

Is the limited slip part the same ?

 

[Guitar Jones]

Cool, thanks

I was worried that one of them was shorter than the other.

I don't plan on swapping parts between the cases.

Is the limited slip part the same ?

There were two different styles of them but they are all 30 spline and will work.

 

[trapster]

and whats the deal with the left handed threads

 

[Guitar Jones]

You mean on the left side wheel studs? lol It's a Chrysler thing they stopped doing back in the 60's.

 

[trapster]

No, the left handed threads holding the ring gear on.

 

[1qwikScamp]

so they dont come loose over extened peroid of time in forward motion. 1971 was the last year of the left hand wheel studs on the right side of chryslers

 

[Guitar Jones]

Ring gears still to this day have left hand threads on them.

 

[1qwikScamp]

Ring gears still to this day have left hand threads on them.

yep everyone i have been into has reverse threads on the ring gear