A couple months ago i was at the track and had bad wheel hop resulting in something breaking. I cracked the PPF, so i replaced that, and there was still a random "binding" noise going slow. Today i pulled the cover and there was a **** load of little metal pieces. I noticed ALL the teeth are stripped off the 4 small gears inside the differential? What would have caused this to happen? Also, the car still moves ok, so what do they really do?

 

dude, replace the diff, I did mine in my old FD 3 years ago and I managed to strip all the teeth off the spider gears, mind you I was sitting in 3rd gear doing a massive skid at the time it let go!
It could be a combination of a few things, old oil, too much power, abuse and just shear age or it could be a combination of all listed.

I still have the old diff in my shed if you want to see some pictures?

That is my 2 cents anyway and I am no expert on diffs.

 

Maybe to much backlash?

 

Oh, the diff is definatley getting replaced. Im just curious why those teeth strip, it doesnt seem like they are under too much stress. Id love to see some pics so i can see if its the same as mine.

 

The two smaller gears here are the ones that are stripped. It looks like ALL of them have broken teeth.

 

The Torsen differential wasn't meant for drag launches. It was meant for easy starting and road racing. Mine blew up at the drag strip. Ever since then, I replaced it with a Kaaz. I hate it, too noisy.

 

Wheel hop at the drag strip can and will damage the stock diff. If you are serious about drag racing, you'll want to upgrade to a Kaaz or use a T2 diff.

 

Alrighty. I have WTB, hopefully i can find a decent prized TII.

 

Find a s4 t11 diff there quiet and strong enough to cut 1.50's 60 ft times and there cheaper. And running low profile tires at the drag strip=wheel hop!

 

Take a read here as well:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fc-diff-fd-637116/

 

You can run RX8 diff's also but I am not sure if they are as strong or stronger.

 

Here is a shot of my blown diff, sorry about the quality as I only have a **** phone for photos. You can see where the teeth were burred down or shorn off.

 

mine looks EXACTLY the same. What symptoms did you have after it happend? Mine drives ok under light throttle, but it binds with even the slightest turn.

 

I was at the local 1/8 mile track when a spider gear jump out on a second gear shift locked the rear and almost put me in the wall.

 

I was lucky I managed to nanna it home (30km''s away) it would drive ok but if I accelerated the rear would slip as a blown clutch would. I parked it up that night and tried to drive it to work the next day (was my dd), it clunked like hell in reverse and got it out of the driveway to have it completely go 500m down the road and I had to get towed home buy some guy in a van!

What were your symptoms?

 

Mahjik is right on the money.

the stock FD makes approx 200 ft pounds of torque at the differential. almost any slightly modded FD makes 300+.

the Torsen, with it's fragile spider gears, is designed purely for road racing w stock power. take it to the drag strip and, well, you know.

while i don't drag, i do put down 364 ft pounds of torque so i switched to a T2 limited slip. add Garfinkle's Engine Torque brace and the Banzai diff brace and you solve most driveline problems including the PPF.

hc

 

Well i was at the track when it broke. I dumped it at about 4k, MAJOR wheel hop then a loud thump. I very lightly crusied down the track,and there was no noise but as soon as i was turning off the track it was clunking bad, then went away going straight. Had it towed home. When i was pushing it down the driveway, it would clunk when i was even SLIGHTLY turning. and feel like it was binding then releasing in reverse.

Car is seeing about 13psi, so im in the market for a TII