I know that a Kia diff will fit directly in a big axle rearend. I also know that a Kia diff with the big axle LSD installed (using the Kia R&P) will also work.

It also appears to me that the Kia diff with a small axle LSD and Kia R&P will work in a small axle rearend. Does anyone know a reason this will not work? The carrier bearings on the LSD are the same for big and small axle. The LSD case seems to be the seem. As such, it seems that the small bearing LSD should work fine with the Kia housing and R&P.

I will probably be trying the swap soon, but wanted to see if anyone has tried this.

Carl

 

i looked into this many (many many) moons ago, here's what i found

the diff carrier, big iron thing, is the same from the R100 to the end of FB production (skipping rx2?), the 94-05 miata is very similar except for the PPF mounts.

the gear set, like the carrier, 79-85 and then 94-05 miata. the non turbo FC would work too, but its got that stupid long pinion, which makes it not interchange with anything else.

the bearings are the same story.

in fact it even looks like the only difference between the big and small axle diff's is (are?) the side gears, the gears the axles actually slide into.

and having worked at a Mazda/KIA dealership, kia used to use the mazda part numbers with an 0K in front of em, so except for things like the gearset, they are literally using the mazda pieces.

kia did get bought by hyundai, and they switched over to the hyundai part number system, so its um stupid.

 

So if only the side gears are different on the LSD portion, it seems that the kia ring gear should bolt directly on and the can go right onto a small bearing axle.

Interestingly, looking at the Mazda part no. list, they only show one side gear size for all GSL and GSL-SE years. If this isn't a typo, it would imply that the only difference on the large and small bearing axles is the outboard (wheel) bearing. Does that make sense. Unfortunately I don't have a large axle to check the dimensions of the splined section. I have a pile of small's.

Carl

 

the 81-83 diff side gears are M020-27-251

84-85 is M050-27-251

the LSD case is M020-27-230 for 81-85

 

Thanks for the info. Also prompted me to notice that my parts catalog is for 84-85. Explains alot.

Still since the LSD case is the same though, it looks like the Kia diff can be used with a small bearing rear axle. Just have to use the small bearing LSD.

Sweet. I'll try it later this summer.

Thanks,

Carl

 

I know this is an old thread (maybe ancient would be more appropriate) but I am curious whether this idea of Kia parts went anywhere.
If so, what Kia model can provide the LSD side gears for the 24 spline axle?
I have a a 1982 SA22C (FB to you guys) which has to remain standard in the road rally class its built for.
An LSD would be a great help!!

 

no you have that backwards, the only difference between the big axle and small axle LSD units are the side gears, the ones the axles go into. so you can use any 84-2005 Limited slip unit, and use your small axle side gears and it will work.

Kia used the Mazda diff, with low gears, but no limited slip

 

The Kia diff is an open diff, so it just provides the lower gears (4.77 vs 3.9 stock FB/SA). You can put either the small or large axle LSD unit from an RX7 in the Kia housing using the Kia ring and pinion without having to reset the pinion depth. If you have a large axle, you can bolt a Miata torsen into the Kia housing.

The Kia diff comes from the Sportage. A search of the site will tell you which gears.

The thing is you will not get an LSD from a Kia (at least that I know of), only the lower gears.

Carl

 

Thanks guys!
I couldn't imagine Kia using an LSD (they're front drive usually) but the reference to the Mazda side gear part no's confused the issue.
So, if I want a lower ratio diff than 3.9, I can use a hybrid combination of the Kia Sportage gear set and the Mazda carrier (LSD or not).
Could be real useful in the 'other' SA22C sitting in the shed, 4.77 behind a good 13B would be a good thing for tarmac hillclimbs or short tracks.
And a Sportage of early 2000's has shown up in the local U-Pull-It (like your Pick-A-Part) so a visit there is coming on Monday.
The collective wisdom is much appreciated.

 

BTW its the FRONT diff on the kia you want

 

Couldn't find a diff in the rear of the Sportage !!
Seriosly, got the front diff yerterday and it sure is a much lower ratio, I think 4.77.
Put that on the shelf for a later project.
Thanks guys.

 

can you pm me
about this thread

 

Hi Izztek,

What's up? For some reason I can't PM you. That option doesn't show up in your profile.

Carl