Well after blowing up a stock carrier a couple years back, I bought a auburn pro series and richmond gear set. Being in emergency rebuild mode I made a mistake and sent it out to a shop to get it done A.S.A.P. It came back with a clunk when turning. I took it back and they couldn't figure it out, told me it was probably because my tire pressure was different...I started suspecting the shop. Anyways I found out it was simply the posi additive, some GM liquid fixed it up.

The gears always had a slight whine, nothing major, and certainly nothing you could really hear over the hooker exhaust. Seems normal for richmonds anyways. Well at the strip this spring on a 2.1 60' on bald street tires I ended up blowing 2 teeth off of the pinion. I suspected my housing might be especially weak, or maybe the very slightly bent axle that causes a tad of vibration over 70mph did it in. The car only traps 105mph so I didn't think It was the power, especially on street tires.

Yesterday I took the pinion out finally and what I found was the pinion bearing was just shy of an 1/8th" from the pinion head, with the shim rattling between. I feel inclined to blame it on the shop not pressing the bearing all the way on. My question is whats the possibility of the bearing slipping down the pinion while tapping the pinion out of the housing, under driving conditions, or when the rear blew? Has anybody seen a pinion come out of a housing without it being pressed tight to the head?

 

When a metal part shatters like that, it produces an extremely strong acoustic (shock) wave that travels through the metal. There's basically no telling what could have happened at the instant it blew up.

That said, I have never seen one do that. The bearing is a drive fit onto the pinion, but it's a light enough interference fit, that I would expect normal loads (let alone drag-race shock loading) to press it the rest of the way on. I can't imagine it being possible for a bearing to remain that way after lots of use; and I can't imagine any shop being sloppy enough to put a rear together like that. That would make it basically impossible to set up the gears correctly. So if the gears worked right before the rear exploded, I'd doubt seriously that it was like that all along. I wouldn't blame the shop.

 

I've never seen a bearing that came off at all during pinion removal, and that was with a very powerful air hammer. I never even saw one that wasn't on all the way in rear-ends that were totally loose or completely destroyed. It's possible the shop was in a hurrey to get it done and just didn't bother pressing it on the whole way.

 

I'd also like to mention that before removing the pinion the preload felt about right on the bearing, and there was no slop in and out, or up and down. So if the bearing was like it is now, before I removed the pinion, the setup was compensated for it.

 

What kind of gears?? I had the same problem with my Richmond gears. I, just a couple of weeks ago, posted a similar issue. My gears did not brake but the rear pinion bearing spun on the pinion gear. I also was told "That has never happened before, it must be something else." I think that is bulls**t. (Now that's two in less than a month with a spun pinion bearing!) IMOP, I think the pinion shaft was smaller than O.E. and the pinion bearing spun because of the increased clearance.
I just replaced my rear pinion bearing shim, used LOCK TIGHT PRESSED FIT and a new bearing. IMOP, I am only going to put maybe 8,000 Miles on the car in the next two years, by then I will have saved for a moser rear.

 

Well I think we just identified your problem. You're correct the richmonds are smaller than OEM. I can get a deffinate difference with the Micrometer next time the new pinion is out of the rear during this setup. I took the same bearing that came off the richmond pinion by hand, (had some light scaring on the inside from spinning) and had to PRESS it onto the motive pinion. This could have been a key factor in my pinion failure.

 

Question #1 How do you know Richmond's are smaller? Question #2 Were your gears richmond that the pinion bearing spun?

 

Because the exact same bearing slipped right down my richmond pinion, and not down the motive without being pressed, as stated above.

Yes the richmond pinion blew off 2 teeth and cracked a 3rd all the way through (But its still attached). The pinion came out of the housing with the bearing slipped down it, and I pulled it the rest of the way off without much effort.

 

Ok. I wasn't sure your gears were richmond. I thought that maybe you were indicating that it was "common knowelge that richmond gears have smaller diameter pinion gear shafts."

I will only be buying Genuine GM gears from hear on out.

 

No not common knowledge, and there are indeed thousands of richmond users out there and I hadn't heard of this happening. But its undenyable when its in your face. Maybe they had a bad batch go out a while ago......

Motives have a good reputation in the LT1/LS1 community (The guys who actually have fast cars)

You might keep them in mind as well.