Well, in light of the fact that my Mazda OEM throwout bearing with only 6000 miles on it just exploded tonight due to mechanical faliure (no, not riding clutch, before this, the throwout bearing lasted well over 10k used, so not my fault!!!), I am trying to find out if anyone else has had this problem by compiling a list of failed OEM throwout bearings with the information of when and where it was purchased and what mileage it failed at. This is to hopefully determine if it was a one-time incident (IIRC somebody else already wrote about this problem), or if it is indeed a bad batch from Mazda's OEM supplier

I'll start it off:

October 2004, Mazdatrix
6,000 Miles

 

Never heard of a TOB actually failing. A LOT of people mistakenly say that their TOB is worn or noisy, when in fact it's the input shaft bearing on their transmission making the noise. This noise is usually heard in neutral and low gears/low rpms, and goes away when the clutch is pushed in. Were it the TOB, the noise would only OCCUR when the clutch is pushed in, since that's the only time that the TOB is contacting the PP and spinning. The noise goes away when pushing the clutch in, because the input shaft of the trans stops spinnning at that time.

Anyway, the only failures of TOB's Ive seen are from sitting for years at a time, and they rust up and lock up. Then when someone tries to get the car going again, the dead TOB eats the pressureplate fingers up, and you have to do a clutch job.

 

Nope, by the looks of it, the TOB actually overheated and failed. Either not properly pre-lubed in the factory or the # or size of (sorry for lack of vocabulary) ***** was wrong. The sound started when the clutch was disengaged and the TOB came in contact with the PP about 2-3 days ago and I was planning on replacing it this weekend, but as we all know about plans and RX-7's getting along...

Anyway, I can't see in the trans through the viewing hole underneath (TII trans), but it feels like the front of the bearing seperated and is not transferring pressure to the PP, and the clutch fork is decended into the bell housing and resting on the sleeve of the input shaft that the TOB slides on instead of the TOB itself. Do note, I am doing all this by feel, not actual sight, so I won't know until I pull the SOB to look at the TOB and the PP. Oh, sorry for all the acronyms, but you get the idea.

 

Sounds like what happened to me this week. Hopefully my clutch, flywheel, TOB, and pilot bearing arrive this Friday so I can replace them and see if the PP or the TOB failed..

 

Check your pivot ball for the fork arm on the tranny front cover plate. When these wear enough, it usually causes premature PP wear, but i would guess that the TOB would take a hit too...

I had a clutch assy that lasted only like 25K because of this...

Mazdatrix has a little explanation of this on their site, look at the tranny front cover picture in their parts catalogue (in the clutch section, IIRC)...

 

Okay, this just f**kin sucks now. Well, I pulled the trans (in a bowling alley parking lot of all places, which luckily I work at), and my hopes for a quick turnaround time for the throwout bearing change quickly disappeared.
Basically, what it looks like is one of the bolts either snapped or backed off on the TOB pilot shaft, and allowed it to begin wobbling. one bolt broke, one fell out, and the other 2 had the heads stripped clean off. Something is seriously wrong with that, too, because I have no freaking idea how that is even possible. I've honestly never seen that happen before, and I've actually seen alot of bolt and (pardon termenology, but) nut faliures. Photos to show my dilema are just below this post!

 

and one of the bitchy exhaust that I had to take off at the engine and broke the top stud on the rear rotor off (even more mother #@$@!# fun...get to pull the engine to fix da bitch)

 

So, the four bolts that hold that seal around the input shaft are forked?

Man, somebody did a bad job of using the correct torque on those bolts.

So, some how the TOB was able to destroy two bolt heads?

That SUCKS!

James

 

Light it on fire and collect the insurance money. j/k.. I contemplated that many times, but my mods are worth more than my car is (4K car, 7K in mods in a year and a half), lmao..

 

Why in the mother **** did you p ull your exhaust manifold from the block? all you had to do was remove 2 17mm nuts and leave the exhaust manifold on the engine! I've seen cars where people remove their exhaust this way, and I have no clue how or why they do so. Seems like the REALLY hard way to me.

 

that same thing happend to me with the header stud on the top in the rear housing and now my motor is out of the car because of it

 

why???

 

^ My guess would be that he's like me and went crazy on it and broke it. I tried to do the 17mm nuts below the exhaust manifold, but couldn't get one to come loose regardless. Ended up having to take a hack saw to the stud and drill it out. Not by choice, just lack of options...

 

hey, anyone know how much the TOB pilots cost from mazda or if anyone has one here? Come to realize that with how wollowed out it is, it also has stress fractures ~1/8" down the sides equally all around. I'm just F'n pissed off right now, though. No matter how much I love my 7, having her break like this just gets me talking about gettting a honda civic (*gulp*) or something...

 

Pilot bearing is like $10, seal for it another couple...

Tranny front cover around $40, throwout bearing? maybe $25...

Fork arm, I dunno, never seen it on their price list...

 

Do you know off the top of your head if mazda motorsports has them? Also, don't need the fork, but the little $5 ball that it piviots on and the pilot bearing is brand spankin new. Like I said, all this stuff was done ~ 6k miles ago only, new tranny and all.

 

Okay, got the low down on it all. Mazda calls it a front trans cover, and they only want $48 for it new. F'n piviot, though, is $32 itself!!! WTF!?

 

Lol, yeah...Just get the whole assy- it even has the new front seal installed in it for ya...