from a 742 case,what would be necessary for me to do in order to install in a 489 case,what parts would be needed.the case is all i have and it has bearings on it.thanks

is the 742 sure grip pig complete? You are wanting to swap the SG innards to the 489 case cuz it (489 open) has a ratio that you are wanting?

SG from a 742 case should be a clutch type. All that is required is the appropriately sized bearings for the case you are using.

Just remember that the gears dont interchange.That and if its a clutch type think about rebuilding it while its out.Just because its a 42 case dosent mean it hasnt had a cone type installed.I have a clutch type from a 66 with 40K that will go into the 89 SG I run now if and when it goes bad.Rocky

You need bearings for a 489 case and a ring and pinion set for a 489 case. You'll need to set up the gears.
Left hand threads on the ring gear!

The 489 case was built with a crush sleeve which is the acknowledged weak spot. You'll need a spacer to replace the crush sleeve, and shims to set pinion fore-and-aft. It is more difficult to set up using the solid spacer, but the crush sleeve does not appreciate jackrabbit starts.

www.doctordiff.com has all the parts you need.

R.

thanks to all.

He will need the sure grip carrier bearings for a 68 and down 742 rear , the hole in the 489 case for the bearing is the same size as the hole in the 742 and 741 case . The bearings for a cone type are different .

Call dr. diff , tell him what you have otherwise you have to order a bearing kit for a 489 and a bearing kit for a 742 to get all the required bearings ... and as suggested set it up wit ha solid spacer.