Trying to get my viscous LSD welded up.
I'm just starting out, I dont have the cash for a real clutch type, and I dont wanna switch over to a whole N/A diff with the shrimpy stub shafts.

I took it to a Local shop to have it done, but they seem to think its nearly impossible.
Has anyone here done this before? or seen it done?




..

 

from what I understand, you cannot weld it

you can however shim it, but the money spent on that would be better used on a real rear end.

 

Let me get your old viscous and we'll find out. Forrest needs a diff for the TII shell i gave him.
/thread jack. i don't see why it can't be done. 240 viscous diffs get welded all the time. there's still a ring/pinion, and spider gears.... if there weren't i dont see how the diff would work at all..

 

I didnt know if the guy was bullshitting me or not... because he told me he couldnt do it, BUT that he would trade me for his 3rd gen torsen, and then weld that up for me... The only thing is that I would still need the s4 Tii stub shafts to make it work anyway.

 

I've heard of plenty of people shimming clutch types from an S4 Turbo, but never a viscous lsd. Are you sure bout that?

and yeah... 240 guys weld their vlsd's, so i figured it wouldn be too bad. I disassembled the whole thing, and it DOES have spider gears, so i dont really see what the issue would be.

 

i really don't see what the issue would be with welding it. i know the S5 TII diff has different sized stub shafts left to right, but you definitely can't "shim" it. S4 TII Diff yes. you can add extra clutch discs aka friction rings.
i'm sure there's similar discs inside the S5 vlsd to make it lock, but for the most part, i wouldn't think you could shim it, otherwise there would be 100 threads in here of people doing this..

maybe the dude just doesnt know?

 

yea the s5 stubs are considerably different lengths (left and right sides), which is why I cant use them in the torsen.
The one shaft is so short that the clip rings on the end of it wont reach the end of the spline inside the 3rd-Gen carrier... aka the stub shafts can creep their out of the diff while driving if they wanted to.
Obviously its not an option.

So i'm not really sure where to go with this one. I wish I knew how to weld myself

 

a vlsd doesn't use friction discs, it is dependent on the oil inside to lock up a diff, which isn't even that good anyway. Welding the gears together is not going to make the oil inside change when the diff locks up.

 

if i am right miatas share A LOT of the same or simalar drivetrain parts so take a look here

http://en.wikipedia.org/wiki/Viscous_LSD

again im not sure but they do point out these diffs are "less efficient than mechanical types" and when they wear out "revert to semi-open differential behavior"

just read up and i think youll be lookin more at that diff you were offered

EDIT: another way to look at it is a viscous lsd it some what like a torque conveter on an automatic tranny... without fluid the power from the motor wouldnt get to the drivetrain(like having the clutch pushed in all the time), now if you welded it you would never stop moving with the engine running(like never pressing in the clutch on a manual)... which is what you want but welding those spider gears wouldnt do that because the fuild is what is "locking your diff"

just trying to shoot you in the right direction mind you i could be wrong but that is my understanding of viscous lsd

 

Youre on point with that... I looked into it further on some other forums, and just welding the spider gears wont do the trick. You have to find a way to lock the Splined sleeve inside the thermal coupling so that it doesnt spin either.