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Flying Dutchman Pilot!
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Discussion Starter #1
I was running a welded diff in my 5speed MKIII a few weeks ago and the car sheared the ring and pinion when launching it off the rev limiter on ET Streets at the track. Car had gotten a 1.63 60's before the ring and pinion failed that day. I had assumed a weld came loose, or the entire diff broke free and the loose welds got into the ring and pinion causing the failure. I have since opened the rear and found no signs of the welded diff failing as far as I can see without opening the diff.

I am worried I just plain and simple sheared the ring and pinion and the welded diff had nothing to do with it which leads me to believe if I get a spool or a solution other than welding I will shear another ring and pinion. On the other hand it is entirely possible all the carnage in the carrier case made it so I could not blame the welded diff even though it was the cause of the problem. I did not take the diff unit apart yet to see if any of the welds were missing. Should I be holding a preload in the rear with a line lock or something similar? How can I keep my carrier together?
 

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If there are no chunks of teeth when you open the cover. The ring and pinion is more than likely not the culprit of the problem. At that point, i would check out your diff for the problem. Is this car street driven or a track only car? If its street driven, i would avoid a spool.
 

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Personally, whatever did indeed fail(be it the welds, shearing the teeth etc) I'd just do up another one and go for it...they are pretty robust(i think they even use the same gears(different pumpking, but same gears) as the Toyota 4x4...

Dave
 

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Flying Dutchman Pilot!
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Discussion Starter #4
Oh you don't understand, the ring and Pinion were SHEARED. Meaning I was missing about 18 of the 39 or so teeth on the ring gear. Most of the teeth were disintegrated into tiny particles. From visual inspection without opening the diff, everything looks intact inside.

The car is a street/strip car, but I change carriers for when I go racing and trailor it to the track now so I am not concerned with a spool in my drag carrier. I have to change carriers regardless because I don't like highway driving with a 4.30 in the car.

Yep they use the same gears as the toyota 4x4. I think I am just going to try it again like you said only this time with a real tight diff, but not welded and find out the hard way what caused it. There is severe shock when I drop the clutch off that rev limiter though(Its a lot worse than the auto), it wouldn't surprise me if its just too much for the ring and pinion with no preload. I just hate wasting good parts like this. The wreckers in Brooklyn have two 4.30 carriers, I think I'll get them both tomorrow.
 
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