TII LSD clearances or Gear Oil in My Hair
 

Ok, I broke down my TII diff to see how worn out it is. I expected it to be pretty bad since this was purchased from a U-Pull wrecking yard. So I'm going through the FSM and I find the standard thickness for the 4 frictions discs and the 2 friction plates are .0787" and the limit is .0748". My friction discs are .0692", .0689", .0696" and .0688". The plates are .0689" and .0695". SO all my frictions are worn out right? That's what the numbers say. All new friction plates and discs should be .4722" total or .4488" "limit" for the 6 frictions. My stack is .4149" or .0573" under new spec and .0339" under service limit.

Following along in the FSM on page 9-39 the tech is to measure the thickness of the 6 plate springs (total value A). Mine measure .4117". I am also to measure assembled thickness of the two pressure rings with the spider in between, the 4 friction discs and the two friction plates (dimension L1). That dimension for my parts equals 3.1623". Calculate clearance number 1: 3.5827"-A-L1= 3.5827-.4117"-3.1623"=.0087" The spec is .0039"-.0098" and I'm in there.

What's messing with my mind is that my frictions are .0339" UNDER the service limit, but the assembled height of everything is within spec. Even more confounding is that if I were to replace my thickest friction (.0695") with a new friction (.0787") I would loose .0092" of clearance which is .0005" less than the calculated clearance.

What gives? RETed you ever come across this? At this point I'm thinking it gets put back together As-Is.

Oh, if you're following along in the FSM clearance 2 is within spec (but toward the high side) at .0128. I could replace one thrust washer to tighten it up if I really felt the need, but I don't.

i wouldn't have bothered pulling it apart unless it had an obvious problem. just because it came from a wrecker doesn't mean it is junk and i hate going by the manual for everything because 2+2 will not always = 4 if you go by the manual word for word. imo, if they aren't scored, burnt or grooved i would have left them alone, if anything replace the spring packs as that is what mainly loses tension and causes the clutches to prematurely fail.

Well, this is me and since the LSD came from an unknown car I pulled it apart. I'd rather pull it apart now rather than have to pull the diff again. The plate springs as they are known in the FSM look quite good. I wish I knew how much crown they should have as that would tell me if they've let go. The parts fische calls the plate springs "seat pinion-differential" P020-27-266. I wonder how much they cost and how quickly I could get my hands on them. Unless someone that has rebuilt a TII LSD pipes up and says something is wrong I'll probably put it back together tonight or Monday.

Ok, I went and measured the inside of the differential case and it is 3.593". The plate springs, pressure rings and friction plates total 3.574" so I have .019" clearance between the diff case and the guts. So it appears I could replace one of my friction plates or discs with a new one and get it down to .010" total clearance, but I think it will work quite well the way it is and not buying parts is free. Plus I want to get this car put together and drive it before I'm 40. That only gives me about 7 1/2 years! :D

BTW, gear oil in the hair is terrible. Happened to me, took a shower with Ivory dish soap.

how much was it from the u-pull place
and is that a good idea to get parts?

Finally! The TII diff is in! I also put in DTSS eliminator bushings so I won't get wonky handling while on track. I still need to put the brakes back together, but it's dark and I'm tired and I don't have new pads yet. This diff swap would have been much faster if I hadn't pulled the TII diff apart and measured everything, but now I know it's good and I got to see Mazda's idea of a clutch LSD. I like the design and the gears are finished very nicely.

Well, it's a place me and a buddy frequent so we got the diff and axles for $100. The diff, however, was missing the driveshaft flange. Thanks to a board member here I got a flange with the nut and washer for like $15. There are certain things I buy used, but I'm not a total cheapskate so I don't go there looking for brake pads and other consumable stuff.

Now it's time to hit the shower.

hehe, this is one of the parts we've had very limited experiences with. :P
We usually swap them for FD Torsens or aftermarket LSD's and be done with it. :)

By the time you buy all the parts, I think you could've afforded at least a KAAZ?

How much would it cost to replace all the plates?


-Ted