Swapping out a Rear Differential...Need Help.

[Jeff Torrey]

I bought my car used, 1992 Viper. Previous owner apparently blew the rear end, because the rear end in the car is a 1995 Unit. So I bought a rear end from a 92 Parts Car, thinking that I would like the car to have an original 92 Rear End (early Viper Rear Ends had a drain plug).

I am now thinking about installing the rear end and have a few questions. I know when you disconnect the drive shaft and 1/2 shafts it's always good to mark them to insure you re-install them in the same location (to make sure thinks are balanced). But if I swap units, is there a certain way that the 1/2 shafts and driveshaft have to bolt up? ...or is it straightforward?

The unit I am installing leaked fluid in shipping, does that mean I need a new seal or gasket? ...or is it Ok to install as is? The unit doesn't leak when it sits upright as installed in the car.

What is the recommended Fluid? I have some Redline MT-90 I could put in it, will that work?

Thanks.

 

[snampro]

hmmm, sounds familiar. I'm in the process of doing the same.

bolting up the half shafts and drive shaft is straight forward, nothing cosmic. locktite the bolt.

check your half shafts before reinstalling, make sure they extend and contract easily. if not they need to be replaced, get a set of Unitrax shafts, they are awesome.

the leak is likely from the vent tube if the differential was at any point upside down. it is likely the vent tube was the cause of the leak. I accidentally left one of mine upside down for a few hours and a little fluid leaked out. if this isn't the case, you may want to seal the cover to the case again. you will use RTV silicone sealant and its easy. be sure to torque the bolts before putting the assembly back on the car.

honestely, though, a lesson learned from my diff swap (actually already knew it) is that you should look inside before installing on the car. you could have problems in there and not be able to tell from the outside.

 

[SNKEBIT]

You should replace the straps for the u-joints when once you take them off. Had a car that made a vibration after a swap. Found out the straps wouldn't tighten up enough.

Also a good idea to look inside case before installing unit. Just to make sure everything looks o.k.