ok so i recently got a rear diff out of a 1991 GTU pulled it form the car myself.
any way i put it in an well i notice the gears are shorter 5th gear at 2 grand is bearly doing 45ish. so it rains an i try out the lsd an it spins one wheel like my old open diff WTF but some times it will lock up WTF so i change the fliud an it does the same thing i put in royal purple 75-90 gear oil but it still does not lock up good is it broke

 

it sounds like it might be a VLSD (viscous limited slip diff) but I might be wrong. and it sounds like it has the 3.90 final drive gear in it.

 

If it's a stock S5 GTU rear end it should be a 7", 4.10, open rear.

The only LSD rear ends in the GTU was 1988.

GTUs had 4.30 LSD.

 

like I said I might be wrong.

 

All S5 GTU Rx-7s had open diffs.

 

not even vlsd.??

 

An S5 GTU is a BASE MODEL.
No BASE MODEL came with LSD.
1986 - 1987 base models
1988 SE
1989 - 1990 GTU
All of them are base models.
NONE of them came with LSD from the factory.


-Ted

 

So does that mean the 88 GTU came with LSD?

 

Did my 2nd Gen RX-7 come with a Limited Slip Differential?
Only the following USA model 2nd gen RX-7s had a LSD from the factory:
86-88 GXL
87-91 T2
88 GTU
89-90 GTUs (however not the 89-90 GTU)
It is also rumored that a few rare 91 coupes with both the A (upgraded the interior trim, added a power sunroof, tilt steering wheel, cruise control, and 4 piston front disc brakes and vented single piston rear brakes) and the B package (leather seating, a CD player, and rear cargo cover) came with a LSD, but you should note that Mazda denies that any FC other than the T2 came with a LSD in 91). You can also tell by looking at the differential as there will be a LSD tag on S4 cars with a LSD.

 

yup all so check out this link
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/specifications-what-did-2nd-generation-rx-7-come-w-options-standard-features-642372/
so if you disagree then read

 

if your diff is 3.909 then you should be at 2,350 rpms in 5th gear going 60mph..
was the diff you got from a GTU with a automatic trannsmission?

 

hmmm I was going to pull one of a S5 GTU that the person said it was locking...and that mine was non-locking. NOT ANYMORE>that wouldnt even be a upgrade thanks....

 

ok the car was a gtus lol an it is a vlsd i put 90 140 i like it was an now it locks up but it has a bad snap to it example

rev to redline slip in the clutch one tire spins then SNAP both wheels spin an then it kicks out side ways

also it does have the 4.30 gear