Hi,

Does anybody know if the Mazda RX-7 rear diff. is the same size as the rear of the Sportage? There are some viscous LSDs available that might just fit.

hmm.. the one that we know is the rx-7 rear diff is same for the front diff on the sportage ..

I heard a rumor that Toyota made the Kia rear axle assy special. Not sure how true that is? It does however look like a small Toy built unit. Just weld it.

Are you serious?! How true do we know this to be? Can it be confirmed?

search for solomiata's posts .. if not look at his site and search there...

If the rear diff for the Kia were made by Toyota, it would be strong and it is not, so I doubt it is a Toyota. Most likely, it is a Mazda prototype.

Hi Rey,

Some of the non-turbo RX-7's (with the 7" ring gear) use the same ring gear mounting and "may" possably interchange the carrier too with the Sporty FRONT diff.

Later Miatas (also with the 7" ring gear) use the same ring gear mounting and "may" possably interchange the carrier too with the Sporty FRONT diff.

Ring gear exchange has been verified but I don't think that carrier interchange has been verified.


The RX-7 diffs that I think "might" interchange with the Sporty REAR is the newer 8" ones from turbo RX-7s.

It seems since KIA farmed out or scavenged most of the parts (short of the body and easily manufactured peices) that went on the sportage, that it's possible that diff could be made by anyone!
I have Robs front and rear hardware now and have been trying to find time to get it in my shop and tear it apart for a closer look. I had too heard somewhere long ago that it was Toyota and that goofy van that toyota made in the late 80's and early 90's with the center mounted engine had a solid axle I think and may have been the same. It probably doesn't matter if it is Toyota as it was no doubt not popular enough to warrant any kind of aftermarket gears.
Everything has KIA stamped on it, but like the engine, we know KIA didn't manufacturer it, Mazda did, so what's to say they stuck with strictly Mazda for all their parts. Ford built their Escort, Tempo, and EXP with the help of 12 different countries and 9 manufacturers, so anything in the automotive world is possible.

this is true so far as i can tell. we need to get a carrier and check it against the Sportage front 3rd. i have mine out, of course and any time anyone finds a Miata or RX-7 diff they want me to check, just send it, i'll check it.

Hi Dave,

I am making a few RX-7 contacts. Can you measure the distance between the carrier bearings and the carrier bearing i.d. on the front and rear Sportage diffs?

Do you remember the axle spline dimensions for front and rear?

I think the front was 26 splines x ???dia and the rear is 26 or 28 splines x 1.07"

So far, I have found out that one version of the RX7 is 26 splines by 27mm (~1.063"). That might match old sportage rear axles.