S5 TII diff in S4 base model (4 lug)
 

Hey folks,

I been diggin around for the compatibility info. I have a very sentimental 87 base model (4 lug) that I'm trying to get back into respectible condition. It's fun to drive and runs great but the open diff is bumming me out. I had a S5 TII parts car that I still have the diff and half shafts from. But I'm not confident that the splines on the hub end of things will work. Can anyone confirm this for me?

I know I also have driveshaft flange issues. Can I just swap the NA flange to the TII diff (like I did on my FB) or do I really need to get a hybrid driveshaft (or go full TII driveline)?

Thanks so much in advance for any help.

Mike

The splines will match up.

I've heard that you can just swap the flange, but I haven't seen it done personally [I have a friend who's planning on doing it though]

5lug rear ends will not bolt up to 4 lug hubs.

You will have to either get the 5 lug hubs, or somehow change the axel stubs to accept the 4 lug halfshaft. you would also have to figure out how to bolt up the driveshaft, n.a shaft will not bolt to a turbo diff. As for changing the driveshaft flange, I dont think its possible, the TII unit is more bigger then a N.a unit if I remember, the flange will not bolt in. I could be mistaken though.

Its not really worth it to swap in a S5 lsd. Seeing how it is a viscous type, the fluid inside the lsd breaks down with age. At most, you will probably get a 20% lockup compared to 100% when it was new. Not worth the headache and time.

If you really want lsd, get a clutch type from the S4. You can just swap out the lsd unit from n.a to n.a. Get one out of a GXL, rebuild it, and you are golden.

WOAH!
some of this is incorrect!/\
The 5 lug hubs will match up to the 4 lug half shafts..I know,I did the swap.5 times!I did not have to change the Diff or the shafts to accept the 5 lug hubs.
Lets shed some light on this ok?
The Half shaft Splines are the same,whether it be 4 lug,5 lug or turbo.
The Thickness of the half shaft is what is different between the N/A and the TII shafts More power,more thicker..get it??
.also the Flanges at the Diff itself are slighlty different so they don't bolt on correctly.
Hence the reason why you cannot use the N/a Half shafts with a TII,and Vice versa.
Now,Driveshafts.
The N/A driveshaft has a smaller input spline at the front of the driveshaft,,you know,where the driveshaft enters the Transmission.So you cannot use a TII driveshaft and shove it into an N?A transmission..and Vice Versa,because the TII trans accepts a bigger spined driveshaft you can't throw an itty bitty driveshaft into a Big hole!.IT won't fit!
That is why they make conversion shafts..like at : www.mazdatrix.com .here is the Link to the Conversion shafts: http://www.mazdatrix.com/g9.htm
..I'm old and Tired so I hope that helps!.Cheers STYX!~

If you put the s5 TII diff into the N/A car,use the half shafts,also IF you can,use the trans,starter,clutch slave,and of course the Driveshaft.
oh,switch out the flywheel and clutch too.
Basically your engine stays N/A.The rest is TII.

and now I know, and knowing is half the battle :P

styx is rt on top of it and this guys best solution is to get an S4 GXL rear diff which will be a direct swapover and have the desirable clutch type diff

Easiest way would be to find a n/a s4 lsd. All would bolt right up with no issues.

i thought it was already covered.

Turbo transsmission to N/a rear end, use turbo drive shaft and drill out the holes on the diff flange.
Personally done this one^ can't find the photo.


N/a trassmission to Turbo rear, use the n/a drivehsaft, same as above, but i think you're supposed to drill the driftshaft instead for more meat?

Everyone, thanks for the clarification(s). I actually have 2-3 full turbo drivetrains (minus diffs & half shafts). I've been procrastinating about doing the full swap if I can find a decent dash to put it in it. So, the flywheel back approach is a decent proposition. Could knock that out in an afternoon. BUT, as mentioned, I forgot the S5 was the viscous type. Damn, I junked 3 parts cars over the last few years that were all S4's with LSD (2 GXL's and a vert). Just didnt' think about it. Oh well.