I have a 1987 Rx7 S4 TII, I have a strange clunking coming from the rear. It only happens when shifting, starting, or stopping, basically, the diff, or driveshaft has too much play, and thats what I hear (I think). Is there a way to rebuild the TII diff? This makes me ask a few questions.

• Diff will be coming down anyway, the seal that connects to the driveshaft is leaking (is this the pinion seal?)
  • While I am there, might as well replace the seals for the axles
  • Is there any bearings I should look out for?
  • If the clunk is from the diff, It is more than likely from the front portion of it, is there a way to tighten this, when I had the car up in the air, there did not seem to be much axle lash.
  • How do I determine my ring gear size without pulling the diff, need to know for the seals I guess?
• If it is the driveshaft I will just purchase a new one, or try to replace the non replaceable joints.

a Little background on the diff

• New diff bushings
• Poly subframe bushings (dont think this is causing the clunk)
• Beefed up the diff mount that tends to break off
• Pinion snubber mod installed.

Let me know what you think, any idea are welcome.

 

You have a s4 t2 diff which is clutch type and arguably the best diff offered in a fc. You can open the diff housing and check the gear backlash with a dial indicator to make sure it’s acceptable now, and after the rebuild.

you can buy new clutch discs, and even oversized mazdaspeed thrust washers are available. You can also shim the clutch pack with self-cut shims. This is a great way to adjust the initial torque of your diff to make it more aggressive which will definitely make the diff more lively.

it’s been a few years since I was messing with fc diff internals, but there are carrier bearings on the left and right side of the diff. Read the fsm on how to move the diff to adjust gear backlash.

I haven’t removed the pinion gear shaft but sounds like you might have to read the fsm and read up on the pinion gear’s bearings and washers.

S4 t2 and s5 t2 have the same ring gear size, s4 na and s5 na have the same ring gear size, t2 bring much larger and pronounced than na.

should try to eyeball the little tab by the 2 nuts on the front diff housing to make sure it’s still at a 90 degree angle and didn’t straighten out, allowing the diff to rotate. It’s a crap design. I want to go in with sheetmetal and box it, weld it to reinforce that tab if i pull the subframe again. Even Hert from hoonigan had a chain securing the front diff….

 

Thanks for the input, Ill look into the diff measurements, I think Im going to replace everything while Im there.