GSLSE rear end with FC 3rd member?
 

I have a GSLSE rear end but its missing the complete 3rd member, but has everything else including the axles. I also have two spare NA 2nd gen complete differentials. I was told a long time ago that I can swap the 3rd member from an FC into a GSLSE rear but I would need a custom driveshaft... True or false?

Don't recall if they interchange, believe they do. The companion flange, what the shaft bolts to, would need to be swapped for the SE one. Doing so will require a new crush tube and resetting of the lash.

it aint gonna work wihtout tons of cash.

care to explain further wacky?

This shows whats interchangeable, doesnt say anything about fc pumpkin into fb housing. i believe its generation specific

http://mazdatrix.com/g5.htm

You could probably buy two or four FB centersections for what it'd cost for a one-off driveshaft.

'94-up Miata centersections should be a drop-in replacement for FB. Haven't tried it.

Truck front 7" centersections (including the Sportage unit) ARE drop-in. Even the driveshaft bolts up. This will leave you with an open diff of course, but you should be able to borrow one from one of the FC centers.

FC came with long pinion shaft so it will cost you $$$ to get a new driveshaft. Its cheaper to just find a GSL pumpkin since GSL-SE R&P suck anyways. LMK if you want a GSL 3rd member and I will get them for you. while we're at it, is this for daily driver or track car as I can get you different gears also (4.44 or 4.78).

This is for the Chump car/Lemons series racing. Track only car. I will need a new drive shaft anyways since I'm going with a TII tranny.

So a GSL 3rd member will fit a SE rear? dosnt the SE rear hold more power? I'm semi-new to 1st gen stuff. Been doing FC's for so long now I forgot all the 1st gen stuff...

PM me with a price shipped to Kissimmee, Florida 34743

Lemons? Ha! You'll blow your entire vehicle budget on the driveshaft, and then they'll crush your car because it looked too fast despite being 121st of 122, or you don't have enough flowers on your hood or some other stupid thing.

The -SE diff is not as good as the 12A diff, gears are about the same strength-wise (not really the weak point anyway) but really, all that matters is that it plugs in. Find a Sportage, weld its diff, plug it in. You don't need good parts for that kind of racing.

Were leaning towards Chump Car since you don't have to have to crazy theme to be able to race. Plus, even a custom built driveshaft looks exactly the same as a stock one. Throw some oil and dirt on there, rub it in to look like old grime, and no one would ever know the difference.

I have checked all the junk yards around here. All the KIA stuff is gone. There is a large rotary community here. So Rx7's and anything related is usually stripped instantly. But I already have a few NA 2nd gen diffs. This is why i want to use it. The parts are readily available, and if/when I break it, it's easier to find replacements.

So, is this a yes or a no on the FC diff fitting the SE or GSL rear?

only one way to find out..... bolt one in and try to stick the axles in the tubes.... you'll know pretty quickly. I know that the Miata LSD is swappable into both an FB big-axle (84-85) housing, and also interchangeable with and FC viscous LSD.... so that makes me believe it will fit, with a custom driveshaft. The only issue I can see is the added length of the pinion may do weird things to rear suspension geometry, and you may need some adjustable lower control arms to set the pinion angle correctly, or you may end up eating the tailshaft off your T2 tranny.

Pinion angle will not change, the diff has zero to do with that.

You may find that you'll have to do floorpan modification for the snot to clear the floor when the suspension is compressed. It should be just BFH work.

The viscous diff MAY not work. Something has me thinking that the viscous diff has the side gears in a different spot so the axles would have to be weird lengths. I could also be thinking of R160s from Subarus, though :) It all blends together after a while... but the clutch pack diff should work, given as the factory upgrade for the diff is a '84-91 part.

Here's a thought. T2 trans? I wonder if you could find an automatic driveshaft and use it. Might even fit as-is, although something tells me that it wouldn't and you'd have to shift the engine and trans back to suit. Oh no, an engine setback for basically free... :)

The pumpkin WILL plug into the rearend housing. The bolt pattern for all 7" pumpkins is the same, same register depth, etc. You can put a 7" Miata pumpkin in an FC N/A housing and vice-versa, and you can put a 7" Miata pumpkin in an FB rearend (and Series 3 axles will fit the diff, too). The only problems you will experience will be driveshaft length and possibly floor clearance.

Thanks Peejay and everyone else, for there info.

I would normally just try bolting things up to see if they work, but my time has been limited lately. So I wanted to find out first before I started tearing stuff down.

well your best bet is to go with wacky racers advice and info...

I recently just swapped a complete 95 kia sportage diff into my gsl-se rear end that i purchased from wacky...

The whole thing bolted up just fine to the rear end, and im running a turbo II tranny...

The flange that bolts up to the diff is using the the same one that came with the kia sportage, the flange on the drive shaft is that from a gsl-se bolt patern, and the imput shaft going into the tII tranny is from a mustang that used the same amount of splines..I can't remember...

But i know that when i had the drive shaft made it was made from mustang parts, like a 98-2000 mach one i believe...in the end i paid nearly $350 for the shaft with fillable fluid injection...nice huh?