The S4 TII diff in my car is making noise that making me worry a bit. So I was wondering what I could do. If it was possible to install the LSD from a FD into the S4 case. The Torsen style seems to be a good happy medium to what I have read. Any help would be great.

 

Simply replace the diff..

If torsen is what you prefer then you want S5 TII diff

I have it, low mile Jspec for $485.00 Shipped

It will cost you more $$ to overhaul your original and swap out the clutch type LSD unit with a used S5 TII/FD unit.

 

Since when? S5 TII diffs are viscous type NOT Torsen, which, as the OP stated, comes from a FD. Anyone paying good money for a S5 TII diff should have their head examined.

And for good reason, a Torsen is a decent solution, but a clutch type diff is superior since it's tunable. If you are really that broke , and can't afford new clutch disks, there are informed people that will buy your S4 TII diff and make your swap to a Torsen cheaper.

 

The only place that I know of that sells the stuff to rebuild them is Mazdatrix. I wanted to rebuild it but I am not sure if rebuilding it would get rid of the whine it has.

 

you might find an FD owner willing to trade you straight across for 3rd members.

whining is worn bearings, either the bearings themselves or they are worn to the point that the gear pattern is off enough to cause gear runoff, which will cause moaning noise under load or decel and possibly both. rebuilding it properly will cure the issue.

 

Oh if thats the case I think I will just rebuild it. Is there a kit out there or do I have to buy the parts by them selfs? I think if there is no kit I will buy the parts little by little.

 

by the way I get noise at both accel and deccl I can make it quiet if I hold the gas pedal just right or push the clutch in

 

well, the clutch pack to rebuild the LSD itself is about $650.. but it can be shimmed with the shims that mazdatrix sells. usually the clutches aren't too severely worn to be reused but they do lose tension over time.

 

what about the bearings?

 

bearings, shims and crush sleeve, seals, etc for the rest is about $335 for a total overhaul in parts not including the LSD portion of the unit. yes they do get quite pricey which is why some people opt away from the clutch type LSD.

not that everything needs to be replaced but you have to expect that worst case it can be close to $1200 to fully rebuild one of these diffs.

 

ouch! and i heard they only last 50,000 miles

 

Like I said....cheaper to swap out the complete diff

I have S4 TII Clutch type...too.. $485.00 shipped

 

^The diff that is in there now I got from you too years ago. It has made noise since day one I thought it was normal untill now. I am not going to spend almost $500 to have the same problem again.

 

There is not a lot of inexpensive options out there other than a used S4 or S5 setup which could be worst that what you have now. With the smaller n/a differential you can at least find a Torsen unit out of a later Miata but those have gotten expensive over the years due to Spec Miata racing.

On a completely different note... I know the V8 guys have found a way to install the Ford 8.8 IRS in their cars, but that is not cheap either. Then again they don't have much of a choice considering the amount of torque they have to deal with and general lack of lower gear ratios in the stock T2 differential. With the Ford 8.8 IRS they also have a lot more gear and LSD options.

Interesting reading though;

http://www.norotors.com/index.php?topic=5084.0