Rear diff swapping questions w/pics

[ScottyS]

Hey all,

My new '91 SS project is cruising along, and I am at the diff portion.

I am swapping a 4.11 tranny in, and have the matching diff from an Impreza. I've been reading all the stuff on here, and that really helped me get these out with minimal effort, thank you all!

Questions:

1) Confirm I have an LSD in the original case - I thought it would have male stubs!

2) I'm still not exactly sure what to swap and how, as not having the male stubs is confusing me.


I just want to make sure what is going on before I tear into it.

Thanks!
Scotty

[Legacy777]

You pulled the male stubs out with the cv axles. Find the roll pin remove it, and you should be able to get the stubs out.

Your 91 is a VLSD. As to the details of swapping it over.....I can't say.

[ScottyS]

You pulled the male stubs out with the cv axles. Find the roll pin remove it, and you should be able to get the stubs out.

Heh, that's funny right there. Do I get an award?

I'll go have a look.

Edit: yep, the pins are there, covered in grease/dirt. Hopefully that method did not compromise anything.

[ScottyS]

Oh, here is some info that a friend sent me regarding the LSD swapping on his SVX.

The principles are the same, maybe details will differ depending on parts used:

I'm assuming your goal is to swap rear differentials on the car, but your new diff is open and you want to swap the LSD carrier into it, right?

To this goal, you crack both diffs open.

Remove the ring gear/carrier assembly from both. Be sure to keep track of the number of shims on each side of the carrier!

Disassemble the ring gear/carrier assembly (i.e. take the ring gear off the carrier) and swap the donor ring gear onto the original LSD carrier.

Install the donor ring gear with the LSD carrier in the donor case. To do this, you will likely have to grind down two bumps on the inside of the case in order for the LSD carrier to be inserted in the diff. Try to take off the minimum material and keep it from getting into the pinion gear. Make sure you really clean out the case when you're done, as any metal shavings are going to wear out the rear-end.

Once the donor ring w/ LSD carrier is installed back in the donor case (make sure you re-use the shims in the correct count on either side of the carrier!).

Then get some thick grease or something and spread is on a few of the teeth on the ring gear. Turn the pinion by hand and look at the pattern it makes in the grease. If you seem to have good contact (i.e. it's not a thin line) you're good to go. If the ring/pinion are misaligned, you'll probably need to have a tranny shop re-shim the diff or it will wear out quickly (or worse, break the gears). As long as you re-use the shims that came out of that diff, you should be fine.

[93forestpearl]

If you look at the two cases you'll see where they machined the LSD case slightly to fit the VLSD unit in there. Not a big deal to grind that off, but keep the shaving out of the pinion bearings. You could swap the ring and pinsion over to the LSD unit, but you would need to make sure your backlash is set properly.

[ScottyS]

OK, so it's pretty clear that these carriers don't swap. One is a Subaru R160, and the other is a "Nissan style" R160 with the bolt-on sideplates.

I will look for a 4.11 Nissan style instead.