My friend has a 97 camaro z28. We were driving the other day and it started to howl or whine a little from the rearend and we didnt know what it was. I told him not to but he kept driving it. Anyway we were on our way to a frinds house last night and he slowly drove away from a stop and he shifted into second at about half throttle and all the teeth on the pinion just shattered off. They are GM 4.10's and his car is making like 350 hp. there was a little leak at the front pinion and i mean like ultra little, but everything else is fine. He just got the car and hasnt even beat it yet.
Does anyone know why this would all of a sudden happen????

 

Somebody abused it. The small 7 5/8" ring gear can't take a lot of abuse. Manual trannys and transbrakes can shock the driveline. Since the ring and pinion are very small they'll break before an axle will.

I'm still waiting for mine to blow up. When it does I have a 9" ready to bolt in.

------------------
Follow my racing progress on Stephen's racing page
and check out the race car

87 IROC-Z SuperPro ET Bracket Race Car
461 naturally aspirated Big Block

Best ET on a time slip: 11.242 altitude corrected to 10.89
Best MPH on a time slip: 121.52 altitude corrected to 125.89
Altitude corrected rear wheel HP: 497.9
Best 60 foot: 1.546

Racing at 3500 feet elevation but most race days it's over 5000 feet density altitude!
Member of the Calgary Drag Racing Association

87 IROC bracket car, 91 454SS daily driver, 95 Homebuilt Harley

 

4.10s were never a factory option, so my question is: who put them in, and how long ago? GM 10-bolts are weak, but don't be too quick to put the blame there. The rearend in my mid-14 second camaro blew out 4 months after the gear installation. I had a hard time believing that the gobs of horsepower from my little 305 caused it, and I was right. The shop openly admitted it was installation error. Then the said it was also a 'racing application' and refused to warranty the work.
It's just an option your buddy should look into, because I've seen many an f-body make 12, even 11 second passes on a 10-bolt.

------------------
Michelle
92 Formula 350
91 Z28

 

Well sure. Mine runs low 11's with the 10 bolt and 4.10 gears but I don't use a transbrake and I don't have a standard to do a high rpm clutch drop. Those 2 things will hurt that tiny ring and pinion more than HP will. Stock engines with a manual tranny break ring and pinions.

How long were those 4.10 gears in the car? Since you mentioned that he just got the car, you have no idea what the previous owner did to it.

 

We have no idea how long the gears were in the car, but they couldnt have been in there too long. The car only has about 71000 km on it and i think the person he bought it off did the swap 2 years ago. The gears were not stock gears but they were GM gears, it is stamped on the pinion, right beside the numbers 41-10, which is 4.10 right??? i think anyway.
So do you think this would be warranteed?? probably not.
Well we did some looking and came up with a set of richmond 4.10's and the install kit for the gears for $300 american in Jeg's. Does this sound like a good deal??? and what do you guys think of richmond???, I hope they are good, hope they wont break.

 

IT happens. My wife's 82 Olds 98 ate the pinion gear. Abused, never. It just gave up after many miles and many gear shifts. However, it's probably a good idea to set the rear end up so you don't have a lot of play when shifting from reverse to neutral to drive. All that clunking can't be a good thing.

------------------
Z's r Best

 

Sometimes the cast iron differential side bearing spacers will crack and cause the ring and pinion backlash to open up, that would cause the whining you heard, then after a while it shattered and the gears un meshed enough to rip the teeth off.