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Broken Ring & Pinion gears

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Guess it was bound to happen.  Prep shop told me that my diff was leaking.  I took it apart this weekend to repair and found that the ring gear and pinion (might have my terminology wrong - the big gear and the little one that meshes into) are missing teeth with the teeth in the case.  from my reading, it looks like this "happens."  Any cause for it?  (Wasn't running low on gear oil).


In terms of replacing them, the car has an old Mazda Comp diff that's never given me any trouble.  Should I just get new ones and have a shop set it up?  Or should I upgrade to a torsen?

chris haldeman

chris haldeman

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Cheapest fix would be to get a junk yard 1.6 open diff and install the Mazda comp unit. It will break again usually rough down shift, rough bump drafting,curb jumping or off track re entries are the cause of failure. Torsen is near bullet proof so the choice is yours. I have not tested speed/power back to back but some have claimed the torsen is slower. Makes sense because it is physically bigger and heavier
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Many threads on this.  1.6 ring and pinion has a finite fatigue life, it is simply too small for the stress we subject it to.  Some guys get 60 weekends, when badly set up (i.e. per the FSM, lol) you might get 4 weekends.  Loss of fluid is FATAL, it barely holds 0.6 qts.  One on-track incident can be fatal - bumpdraft while braking, wheel-to-wheel, wheel-to-wall, off road excursion, stalled-engine spins, etc.


The problem is the 1.8 unit is absolutely, unequivocally, slower.  I only recommend it for rentals, enduro cars, and people who don't care about laptimes.


85% chance the MazdaComp unit itself is salvageable. 

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