Gears & Axles - Who has broken a 12 bolt?

I have been reading up on rear ends and I'm pretty sure that I am going to get a Strange 12 bolt in the future (8.8 inch is definately out now with the Extreme Chassis stories). But I have heard that the 12 bolts can break. I was wondering if those who have actually broken a 12 bolt (Strange or Moser) or know of one that was broke could post up some more info. Maybe the options that it came with, what actually broke, how much power the car has, what rpm it was launched at, etc. What options are actually worthwhile to upgrade to when getting a 12 bolt? By the way, I want a posi (not a spool), and this is for a M6 car. What power level should be considered for upgrading to a 9 inch? I am planning on eventually having 425-450 hp running with full weight. And I don't race very much, but I want no concerns if I do race. So who all has broken a 12 bolt? Thanks :hail:

12 bolt posi's can break on slicks but spools hold up very well. I havent heard of too many 12 bolts breaking in our cars. If you are going to run a posi full time and have a lot of power (over 470RWHP) I would consider a 9 inch. Though 9 inch posi's arent indestructible either

:cheers:

I think seven different guys in my club have broken the Strange 12 bolt. (All M6's) I got one and I like it though.

Can you give some more info on these people that broke the 12 bolt (concerning the things I mentioned in the original post)? That would be really helpful. Thanks!

Chris is right. It's the posi unit that doesn't hold up well. I have seen many guys break their Eaton posis, one was a bone stock M6 with 12 bolt housing.

I ran my 12 bolt with posi into the 9's. You can guarantee that I was hitting it hard. The only problem that I ran into was gear whine. This was taken care of by changing from a tapered crush collar to a solid one.

Now I run a spool, just in case. The posi is sitting up on a shelf ready for re-entry into batle.

Roman

I ran my 12 bolt with posi into the 9's. You can guarantee that I was hitting it hard. The only problem that I ran into was gear whine. This was taken care of by changing from a tapered crush collar to a solid one.

Now I run a spool, just in case. The posi is sitting up on a shelf ready for re-entry into batle.

Roman
strange or moser rear? eaton posi? just curious, thanks!

Can you tell me more about changing the tapered crush collar to a solid one? Does this affect driving on the street at all? Is it hard to install? How much does it cost? Where do you buy one? Along with not wanting to break the rear end, I REALLY don't want it to whine. So if this is an option, I would like to hear more about it. Also, is a spool a bad idea for a daily driven car that sees quite a bit of highway miles?

strange or moser rear? eaton posi? just curious, thanks!

KTRE rear with a 800 lb eaton posi. But unfortunately these were bought out by Mark Williams and are no longer sold (to the best of my knowledge)

Can you tell me more about changing the tapered crush collar to a solid one? Does this affect driving on the street at all? Is it hard to install? How much does it cost? Where do you buy one? Along with not wanting to break the rear end, I REALLY don't want it to whine. So if this is an option, I would like to hear more about it. Also, is a spool a bad idea for a daily driven car that sees quite a bit of highway miles?

I by no means know much about rearends, so if anyone can give a more professional explaination be my guest. But here I go.

Crush collar, crush sleeve is the way that the bearings are pre-loaded in most applications. The Solid spacer is installed with shims and is a more robust means of preloading the bearings. From what I understand this is fine on the street. The Solid spacer cost me around $30.

The spool is mainly preferance, it does take away some of the streetability. In my case, I don't care. It depends on what level you want the car to go to. There are other options, detroit locker, posi........But these will break at high power levels.

Roman

It's almost always the M6 guys that break the 12-bolt posis. I ran alot of low 10 and high 9 second passes with my Moser 12-bolt and HD Eaton posi with never a problem. This was with a TH350 and a transbrake.

KTRE rear with a 800 lb eaton posi. But unfortunately these were bought out by Mark Williams and are no longer sold (to the best of my knowledge)

i think mark williams is the only seller of the ktre's i called them begining of this year and they still carried them. i plan on doing one in the future

any real difference between strange and moser? I know that eh strange is more of a bolt in, nad the tq arm is attached better. I am leaning towards going with a strange, 4.30's, 33 sp. axles, and the best posi unit that I can get. I am also gonna have new brake plates and reluctor rings installed so I don't have to tear down my old rear. Anything else that I am missing?

It's almost always the M6 guys that break the 12-bolt posis.

Yup, I keep on forgetting that important info. :)

Thanks.

Roman

any real difference between strange and moser? I know that eh strange is more of a bolt in, nad the tq arm is attached better. I am leaning towards going with a strange, 4.30's, 33 sp. axles, and the best posi unit that I can get. I am also gonna have new brake plates and reluctor rings installed so I don't have to tear down my old rear. Anything else that I am missing?

It depends on where you plan on ending up with the car. 1350 u-joints?

Definitely go with the 1350 u-joint. You also might consider gun drilled axles and you may as well have the installer weld LCA relocation brackets on.

ttt....anyone else?

I thought of a couple questions that I would like to know in addition to more info on people breaking the 12 bolts. First, you say that the posi breaks with M6's. Is this just on the weaker posi or the upgraded HD Eaton posi? Also, if a posi does break, do you just replace the whole unit or is it fixable? I know basically nothing about rearends, hence this thread :) Besides the posi, what can break easily? Is there anything that breaks that is not easily fixed (like would you need a whole new rear end)? Is it just people putting down 450+ horsepower on slicks with 5000 rpm clutch dumps, or have they broke under more normal circumstances? If I don't race much but plan to have quite a bit of power in the future (up to 450 hp or so) is it overkill to look into a 9 inch? If they both have posi's (no spool or locker), are they basically the same strength wise?Does a 12 bolt or 9 inch typically have more gear whine? Sorry about all the questions, I just want to learn more before I spend a lot of money on a new rear. Thanks! :hail:

any real difference between strange and moser? I know that eh strange is more of a bolt in, nad the tq arm is attached better. I am leaning towards going with a strange, 4.30's, 33 sp. axles, and the best posi unit that I can get. I am also gonna have new brake plates and reluctor rings installed so I don't have to tear down my old rear. Anything else that I am missing?

I would also like to know the difference? What about compaired to a ford 9?

I ran my 12 bolt with posi into the 9's. You can guarantee that I was hitting it hard. The only problem that I ran into was gear whine. This was taken care of by changing from a tapered crush collar to a solid one.

Now I run a spool, just in case. The posi is sitting up on a shelf ready for re-entry into batle.

Roman


Same here. I'm on my 3rd gear set. Never broke them, they just either started out whining or whined after making a few hard passes on slicks. I've had 2 sets of Moser/US Gears and both were noisy as hell. I have Motives and were dead silent until going to the track a few times. Now they have a slight whine but nowhere near as bad as the US Gears.

Here's my advice if you want a quiet rear. Buy a housing, axles and posi from Moser or Strange and have the rest setup locally by someone who has some credentials. Get a solid pinion spacer and Motive gears. Or, just buy a complete unit and take it to have new gears/spacer installed and sell the gears that come in it.

The Strange housing is a direct bolt-in. The Moser has 3" axle tubes and you'll need to redo your sway bar mounts to accommodate them.

If you get the larger 33 spline axles they have to bore out the posi housing for them to fit, making it weaker. That's where the posi usually breaks. That or the spider gears inside.

Get the 33 spline axles star flanged and gundrilled too if possible. Those axles are HEAVY. Doubt they'll drill a 33 axle though. Probably need 35's to do that.

Hope that helps.

Craig

Thanks for the info! I've learned a lot in this thread. I am still leaning toward the Strange (for now, I probably won't get this for quite a while). It comes standard with a 33-spline axle and I would want the HD Eaton Posi.

Anyway, I was wondering what "star flanged" and "gundrilled" mean. If I bought the complete 12 bolt kit, how much would it cost to have this done?

Also, any idea of how much it would cost and how much trouble it is to put the solid pinion spacer in? I want the complete unit if possible, and I don't want to have to buy more and sell it if possible as well. I am thinking that I could buy the complete Strange kit, and if it whines, I could have the solid pinion spacer (and maybe gears) put in. Or is it a better idea to put the solid spacer in beforehand?

How do the Strange gears compare to the Moser/US and the Motive as far as whining and strength?

And I would still like to know about things from my last post: Is it just people putting down 450+ horsepower on slicks with 5000 rpm clutch dumps, or have they broke under more normal circumstances? If I don't race much but plan to have quite a bit of power in the future (up to 450 hp or so) is it overkill to look into a 9 inch? If they both have posi's (no spool or locker), are they basically the same strength wise? Does a 12 bolt or 9 inch typically have more gear whine?

This will answer most of your questions:
http://www.strangeengineering.net/

A 9" can handle more power, but is heavier and robs more HP than a 12 bolt. And you can't get 3 channel ABS in a 9" either.

any real difference between strange and moser? I know that eh strange is more of a bolt in, nad the tq arm is attached better. I am leaning towards going with a strange, 4.30's, 33 sp. axles, and the best posi unit that I can get. I am also gonna have new brake plates and reluctor rings installed so I don't have to tear down my old rear. Anything else that I am missing?whats the difference in the TQ arm mounts? does anything else have to be modified for either one to bolt in or do they just... bolt-in?

The moser uses 4 small bolts that backout to hold the torque arm in, where the strange uses the stock long bolts and hold way better than the moser 4 bolt setup

All the guys that I know that broke em had the Eaton posi. Some were heaed and cam cars, some were cam only, and at least one guy I know I can think of off the top of my head had a stock internall motor when he busted his. He did have a kevlar Mcleod clutch and ET Streets on though. I've got about eight passes on mine and it wines (4:10's).

One of my buddies broke a 9" in his 69 camaro.....That was a fun experience. How much heavier is the 9" compared to the 12 bolt?

I looked on Strange's website and didn't find much. I still have a lot of unanswered questions from my old posts if someone could help. Thanks.

t t t

i highly doubt that people with 450 hp are going to break a 12 bolt easily...i would imagine to break a 12 bolt you would be needing upwards of 700hp...but then again i don't know much about the rearends..i've just seen many people with that much hp not break anything

How bad is a spool to drive on the street. I dont daily drive the car but i do drive it on the street. The posi is more expensive but the spool is stronger, so im not sure which i should go with.

i highly doubt that people with 450 hp are going to break a 12 bolt easily...i would imagine to break a 12 bolt you would be needing upwards of 700hp...but then again i don't know much about the rearends..i've just seen many people with that much hp not break anythingin an auto car that may be true but when you pop the clutch on a stick shift its 10 times harder on the rear than anything but a transbrake in an auto.

t t t

3 channel is for ABS only, and 4 channel is for ABS/TCS right?

3 channel is for ABS only, and 4 channel is for ABS/TCS right?

Correct...

Well I am a stock internal car and have been through 7 ring and pinions in 8 thousand miles in my moser 12 bolt.They get so loud after a few passes that ya can't stand it .
I've tried several different installers and us gear,richmond,motive, ring and pinions. I've
had the best luck with motive so far.I think a 9" is needed in these stick cars the way we shock the driveline.

One of my buddies broke a 9" in his 69 camaro.....That was a fun experience. How much heavier is the 9" compared to the 12 bolt?


My 9" with 35 spline axles, and locker weighed 30 lbs more than the 12 bolt it replaced. I went through 3 sets of gears in about 4000 miles with my 12 bolt. They never broke, but I couldn't stand the noise anymore. Setup of the rear was NOT the reason for the noise. I had converted the 12 bolt to 1 piece axle bearings, like a 9", and had a solid pinion spacer too. After about 15 runs on QTP's the gears sung like the church choir on Sunday. :judge: My 9" has some noise on deceleration but virtually none cruising with any pressure on the gas pedal. This is with 4.57 gears in the 9". M6 car owners should just say no to a 12 bolt and get a 9". :nod: ;)

Bruce

so auto with 12 bolt and spool is fine then?
even if later th400 and transbrake?

friend of mine says
spools are bad for daily drivers
chirp around corners
eat up tires quickly
is this true?

I broke a eaton hd posi, the spider gears are the weak link in a 12 bolt.

Moser is in the process of coming up with a better set up than the Eaton. I make only 400 or so rear wheel hp. But dump it at 6k on ET Streets.

If you have an A4 chances are you wont break a 12 bolt. But if you are running an M6, I would go 9inch. Or wait and see the new unit Moser is developing.

Moser told me this 12 bolt with Eaton HD posi woiuld be indestructable in my 400hp car. Call them now and see if you get the same response.

Rob

What is the weight differnce between the 12bolt and the 9". I know the 9 weighs more but does anyone know how much more?

How bad is a spool to drive on the street. I dont daily drive the car but i do drive it on the street. The posi is more expensive but the spool is stronger, so im not sure which i should go with.


They are not bad at all or not near as bad as people say. It does change your turning habbits slightly. The first true spool I rode in, i didnt even know it was there untill i asked what kind of rear end he had in the car. If your worried about tires then I suggest you dont get drag radials. But dont listen to me, I run a trex in an A4 for a daily driver, go find someone that lives close to you and find out for yourself.

What is the weight differnce between the 12bolt and the 9". I know the 9 weighs more but does anyone know how much more?Umm, read 3 posts directly above yours.

Locker/spools are okay for highway driving, they are more annoying around town.

My strange 12 bolt Blew up tonight at the Track :shiner: 5K clutch dump ,ET streets, something felt odd at the end of the track, I had a hard time turning off the track. It feels like the Posi unit....no more clutch dumps for me. These parts are way to expensive to be replacing twice.

Man that sucks. I was just wondering if you can tell us more about it the rearend. Especially what options it had on it, how much it has been raced, etc.? Also, I know it broke, but prior to that, did it whine? Was this just the bolt in unit or did you have someone set it up? What are your future plans as far as the rearend? Thanks and again...sorry about the rear end.

No, it wasnt quiet but I have heard louder. Its a Strange 12-bolt rearend w/4.11 gears, custom axles, 400# HD carrier, ABS, & LPW aluminum cover, Mark Williams carbon fiber driveshaft w/Spicer 1350 u-joints. That was the second allmost WOT clutch dump the last one on ET streets spun, I guess the track was better preped this time cause it hooked great. I really dont want a Drag race car rather a fun/fast street car that wont keep breaking.

Thanks for the info. So was this a Strange bolt in unit, or did you buy the parts and have someone set it up? Sorry, I'm just confused. I'm looking for the same thing--more of a fast street car. Just trying to get it all figured out before I decide to do it.

My strange 12 bolt Blew up tonight at the Track :shiner: 5K clutch dump ,ET streets, something felt odd at the end of the track, I had a hard time turning off the track. It feels like the Posi unit....no more clutch dumps for me. These parts are way to expensive to be replacing twice.Put a Spool in it and keep dumping. :drive:

Thanks for the info. So was this a Strange bolt in unit, or did you buy the parts and have someone set it up? Sorry, I'm just confused. I'm looking for the same thing--more of a fast street car. Just trying to get it all figured out before I decide to do it.

I had a Strange with 33 spline axles, solid axle bearings and pinion spacer, and it was so loud I couldn't stand it. 3 different sets of gears, and no it wasn't a setup problem. Have a 9" with 35 spline axles and a locker now and couldn't be happier with it. If you have a M6, get a 9". I've had both. :judge:

Bruce

Mine was also farley quit until I took it to the track. Now it makes all the same noise you all are talking about.
But now it is Broken! It broke the driver spider gear with Nitio's on a 1.9 60' and only 355HP.
Moser 12 Bolt Eaten posi 33sp.

Mine was also farley quit until I took it to the track. Now it makes all the same noise you all are talking about.
But now it is Broken! It broke the driver spider gear with Nitio's on a 1.9 60' and only 355HP.
Moser 12 Bolt Eaten posi 33sp.

Those spiders are the weak link. I wouldn't put another Eaton in there if I was you. I'd go for a locker, or Moser is supposed to be working on something new that will hold up. Give them a call. They know the Eaton wont hold up in a M6 F-Body. The car is too heavy. You probably have an upgraded clutch too right?

Rob

Yes, I upgrade to 33 spline and HD 800 lbs clutch.

I've got an EATON prop posi for sale with 3.73's set up for 3 channel if ya need. It is in the For sale section. It is 33 spline also very little miles on it and a couple passes at the track. No whining or anything. I just ended up going 9" got a deal you would have to be stupid to refuse. :D