I always here people talking about breaking a 10 bolt but since there is more than 1 part to it what specific part and/or parts are they always breaking? Is there any way to fix/prevent it easily? I just don't understand how the problem with it can be so massive that it is more cost effective to buy an entire new rear end than fix or upgrading the original one. Would someone please enlighten my as to why I am wrong.

 

Usually, the teeth on the ring gear break.

There's no real way to completely stop it, but you can make the 10-bolt stronger. The biggest reason for failure is due to the use of the crush sleeve, which controls the pinion depth. As the sleeve compresses beyond factory specs, slop develops in the pinion to ring gear mesh, which causes eventual failure. To minimize this, many of us have gone to a solid spacer, which in theory, would eliminate the for/aft movement of the pinion.

Another area prone to causing failure is the bearing caps. When they twist/spread, it causes issues as well. This can be "helped" by replacing the OEM bolts with ARP studs, which utilize nuts on both sides. Also, using a differential cap with pre-load bolts puts additional pressure on the center of the bearing caps, to help hold everything in place.

The housing can twist as well. Using a diff. cover/girdle may or may not help, but it won't hurt.

Finally, twisting of the axle tubes can result in failure. Many people have welded the tubes in place to the center pumpkin. Some have even gone so far as to reinforce the tubes with additional bracing.

For the most part, the best bet is to avoid sudden shock to the gears. Slicks and clutch drops from 3,000 are proven methods to killin' the rear. Automatics tend to be more forgiving, as the torque convertor minimizes sudden shock to the teeth. Remember too...the higher numeric gears have less teeth to spread the load. So they tend to fail more frequently than the smaller numerical gears.

For what it's worth...I made the above mentioned upgrades to my rear (minus the tube mods.) and have had no issues. I have converted my car to auto-cross trim, so my drag days are behind me though.

 

Al pretty much summed it all up nicely!

I've had 2 teeth come off the pinion gear of a set of 4.10's, and a chip off the corner of a tooth on the ring gear of a set of 3.73's. I NOW have ANOTHER set of 3.73's that just recently bit the dust, but I haven't pulled the diff apart yet to see what happened this time ... I suspect a tooth off the ring gear, but it could be the pinion gear (again) this time!?

My gear breaks have all been from road racing on a very TIGHT road course, which somewhat resembles an Auto-X course. The 4.10's were actually behind an automatic tranny, but it was doing repetitive 3rd-->2nd downshifts coming out of every corner, and I guess the gears finally had enough!

Unfortunately, you can do all the "upgrades" in the world, but there's no way of strengthening the small gears. Inevitably, driver abuse will kill the 10-bolt.

 

My main concern is with Drag racing. I want to race next year and have planned on having a race car, but if I can't have it ready for the beginning of the year I was planning on entering my DD until it is ready. It has 3.42's so that at least makes me a little hopeful and I don't plan on doing and 3k clutch drops because most of the time I will be leaving off idle. I just don't want to throw a set of drag radials on the back and immediately blow a rear apart.

 

i broke 3 teeth off my pinion with a measley 2k clutch dump after my header install,,

 

On my 99 Formula and on my 96 Firebird V6, both A4, I have had ALL of the bearings go out and start making an awful grinding/whining/howling noise. From what I have heard, the whining/howling was caused by the pinion bearing. I know some rears just are noisy, but this was bad. Both times the only option was a new rear (at least that's what the shop said). Why do these bearings fail?

 

Failed bearings can often be due to having too much pre-load on them when setting up the diff. You NEED pre-load, but too much of a good thing can sometimes be a bad thing . I've had a pinion bearing go bad, and a carrier bearing. I KNOW that I burned myself on the pinion bearing ... I'm pretty sure I over-torqued the pinion nut when assembling the diff (book calls for ~20 - 25 inch-pounds, I probably put ~40 - 50 on it ... did it by "feel", and didn't use a torque wrench ).

However, you CAN change ALL of the bearings, without changing the whole carrier. The bearings aren't exactly "cheap", but they're way cheaper than a whole carrier!! (and changing the carrier still doesn't address both of the pinion bearings ). Basically, your shop is FULL OF $H!T.

 

As far as doing drag launches with a 6-speed, be "nice" to the car when you launch . Rrrrollllll onto the throttle "gently" (but quickly) from no more than ~2000 - 2500 RPM. I managed to knock off a few consecutive 12.9's & 13.0's, on drag radials, launching at no more than ~1500 - 2000 RPM (with 3.90 gears in the back). My best time was a 12.87 (all were 1.9xx 60' times). You just have to figure out how to launch smoooothly (like an auto) without giving the diff a hard SHOCK, but do it quick enough that you don't bog the car down too badly .

OR, go ***** out, hope for the best, and fix whatever you break!

 

I recently pulled apart a working 10 bolt out of a 6 speed. Mileage is unknown but I dont think it was very high. I do know for a fact the 10 bolt was quiet and functioning perfect. i noticed very slight slack in the carrier bearings. It seems they had almost zero preload, I guess from wear. I would suggest for anyone who drives their car hard and wants to give the 10 bolt a chance to last, refresh it frequently. I would swap all bearings/races throughout before next season.

 

It's all about mass, design and intended use. The 10 bolt 7.5 is a light duty rear agreed? Intended for S-10's, low HP/Torque vehicles yes? For sure not your High Performance rear... never intended for big abuse. Their is a reason a 9", S60, 12-Bolt, Corporate 8.5, etc... will take it. One is just everything is beefier thus the increase in weight. Working with the 10 bolt 7.5 you can plug the holes in the dike with your fingers but even then you run out of fingers. Now if someone made Blutonium (no such thing) gears, etc... maybe but just not going to happen.

 

It's a 10 bolt....Enough said.

 

I don't mean to hijack, but how common is breaking a 2.73 or 3.23 from an auto?

 

this thread is exactly what ive been wondering these past few days. i even went to the bank to ask if i could get a loan for 1K-1.5K for a 12 bolt. which i was approved for, dangerous thought.

I think i'll drop 500 into the 10 bolt and see what happens. my car is a street queen for the most part. havent even had it to the track yet and ive owned it for a year.

 

I always admit to the honest truth. I have beat the snot outta my 10 bolt with DRs and it is smooth as butter. No problems. Although I have seen M6s wear a 100K 10 bolt's *** out on street tires and not much more then factory power levels at the track.

 

im putting down 412rwhp and I was doing 4-5k launches last night at the track over and over again without a single problem. My 10 bolt is brand new factory quiet and I have a full suspension under me and a RAM powergrip HD clutch but I was on street tires.

3.42 gears

 

It's like rolling the dice with a 10 bolt. I'm not trailered so really wanted the added security. I also don't want the ring gear to break and send me into the wall or another car. Just like when I ride my Motorcycle I wear a full face helmet... what chance are you willing to take?

I will tell you this though. I have a friend with a 3800 lb Regal that has been on the same 9" for years and years going to the track, bracket racing, running on the street, hitting it with a 300 shot going in the 9's and has only freshened the bearings/races up on it. Never broke it once and who knows what it had done to by the previous owner.

 

I've broke my posi unit twice (Zexel-Torsen) and the gears survived....

 

I contacted a buddy of mine from high school who had an '01 SS. He said he would always launch in 2nd gear. He couldn't remember what RPM, he sold the car 4 years ago, but he said it was much safer and his 60ft times were in the 2.0x range. Anybody do this?

 

With an auto, you will last alot longer. But if you have a m6 with slicks you can bet it will break. The 10 bolt is weak and can get away with slicks at the strip but just wont last very long like that. To put it in perspective, put 11-12psi on a stock LS1 block, will it work... Yes but not for very long beating on it. I have busted the stock Zexel and 2 sets of gears (3.42s and 4.10s). I have been to the track with slicks with 4.10s in the 10 bolts and it made quite a few passes, but eventually started chewing up teeth on the ring. All of that was with boltons though, and before the h/c. Never broke an axle though.

 

I did that, but with street tires at the track. The main reason I did, was because I had 4.10s. Trying to get any traction in 1st with 4.10s at the strip is impossible lol.