I have verified that the splines on the 28 Spline Rear axles are larger than the 26 splines. No precision measurements yet but it is aproximatly 28.5 or 29mm.........
This does look positive for Mazda RX-7 Turbo LSD's fitting the Sportage and possably ARB having the tooling for splines to make a locker for our Rear axle.
What I have found out is that the non-turbo RX7s have a 7" ring gear and the newer (85+??) have the same splines as our front diffs.
The turbo RX-7s have a larger ring gear and MIGHT be the same size as the Sportage REAR.
It seems that the Turbo RX7 is a 30 spline diff.
Are we sure that the Sportage rear axles are 28 splines not 30 splines? Much of the RX7 specs seems to be just repeats of old info that may be wrong. Could our 28 spline rear info be wrong too?
No disrespect, but you seem to be contradicting yourself.
The other issue is that
axle diameter does not always equal
spline diameter, this depends on whether they are rolled on or cut into the axle ie
___/--------| rolled
.................|
or
____________
....\---------| cut
..................|
where:
------ = spline
....... = metal
_____ = edge of metal (axle diameter)
G'Day Gary,
I don't think that I have contradicted myself but is kind of late here. The contradiction seems to be some info on the web.
We do have verification of the size of the Sportage 26 spline FRONT diffs and ring gear.
We DO know that the splines of the REAR axles that have been called 28 spline axles have larger diameter than the 26 spline ones.
We also know that the REAR axle shaft is larger than either spline diameter. I have the figure somewhere but I think it is around 32mm.
What I have not been able to verify is whether the 28 spline axles really are 28 splines or are they 30 splines.
Also with Mazda and Kia's part numbering methods, we can't really tell if the rear Sportage and rear RX7 TURBO ring gears are interchangable.
All we really know is the Sportage REAR diffs and the RX7 TURBO REAR diffs are larger than the Sportage FRONT diffs and the Sportage FRONT diffs are nominally interchangable with the 94+ Miata REAR diffs and the RX7 NON-Turbo 26 spline REAR diffs.
At this time we can only speculate that the Sportage REAR diff is the same size (but possably different splines) as the RX7 TURBO diffs. The only source of info on the RX7 TURBO axle splines is SoloMiata's site which states 29mm x 28 splines but both of the RX7 Turbo diffs on ebay are reported to be 30 splines by their sellers.
Just had a thought: I wonder if the Sportage rear splines are actually 30 splines with 2 splines 180 degrees apart removed?
What we really need is someone with a newer rear axle or diff out of the vehicle that can do some counting and measuring.
