Open? .... Posi?

-
fish'sfish

fish'sfish

Active Member
Joined
Mar 11, 2010
Messages
30
Reaction score
5
Location
Chicago
I had this center section sitting for about 15 years i pulled it out to use it and i think it is a open rearend...? it is a 489 case with 411 gears ... who would put 411 gears in a open rearend?
The other picture is the 741 case out of the car it has 3.23 gears in it.
Can the posi unit be swicthed from 741 case to 489?
Also is that rearend Open?

DSCN3917.jpg


DSCN3919.jpg
 
1st one looks open to me. 2nd looks like it might have the cone posi in it. Dont think its rebuildable hope someone jumps in and lets ya know about the posi unit. I think it is the cone though.
 
Is it pretty easy to swap....do you have to reset gears or do they stay in case?
 
Don't need to reset the pinion depth to remove the suregrip from the 741 and put it in the 489 since the pinion gear doesn't need to come out to remove it. Geof
 
you will need to use the bearings and races that are on the suregrip, swap the ring gear over to it, and then set the backlash and bearing pre-load. Pinion can stay in the case and as cosig stated, it should not need to be messed with at all.
 
..........just remember the crown bolts r left hand thread.............55 lbs tork...........90 lbs on cap bolts.......6-10 backlash................kim.............
 
Before you swap it, take a backlash reading on the 489 housing/gearset. When you put the sure grip in, reset it to that backlash setting.

As Kimmer mentioned, the ring gear bolts are left hand thread.

So you don't have to beat the ring gear to install, make sure the wife isn't home, turn on oven to about 200* and warm up the ring gear for about 10 minutes. It will drop right on and start the bolts, don't go crazy tightening them, just get them started.
 
You must log in or register to reply here.
-

Back
Top