Can I put a '87 LSD into my '85 GS rear end? I think I read that it can be done but I'm not sure. Yes, I know a search will reveal the answer, but I'm working 12 hour days 7 days a week right now and to say I'm short on time would be an understatement. So I'm hoping someone will give me the answer out of the goodness of their heart. Thanks!

 

even if it could its not a strait swap or worth the trouble when you can get a 84-85 posi center for $100.

 

Yep. Viscous LSD's suck.

 

Not all FC LSD's are viscous,many are multiplate like the 1st gen units.
Some LSD carriers can be swapped and some cant,it depends on what trim level the donor FC is.Its not worth swapping in a viscous unit,as they do suck like Moses pointed out.

Due to differences in the ring and pinion between the 1st gen and 2nd gen rearends,only the carrier itself will swap.Whatever type LSD carrier you end up running,it will require you to swap FB gears onto the LSD unit,then reset all differential lash,pattern and preloadsettings.

 

Thanks for the info guys. I'm gonna say screw all that crap! I had a line on a cheap one if I acted quickly. I'll hold out for a GSL unit instead. Thanks again.

 

I've done a little research into this and I have heard that the FC N/A diff will fit if you buy a KAAZ diff.

 

I know that aftermarkets like the Torsen sold by Mazdatrix,will fit later 1st gens and some 2nd gens.
What Im not sure of is which 2nd gens.The TII has big gears and axles,but Im not sure if the axles and internal guts of the TII are bigger than BOTH the 4 lug base cars and the 5 lug high end N/A cars like the GXL,GTU and Vert.
Usually when FC guys talk about rearends and alxes,its just plain "4 lug" or "5 lug".

 

All NAs are the same, TIIs are different. NAs have a 7" ring gear, TIIs have an 8". As far as the lsd units by themselves, don't know.

 

The LSD units are the same for all the N/A cars 84- on.