matts22

iTrader: (2)

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

CHRISPY

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

INMY01TA

iTrader: (1)

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.

matts22

iTrader: (2)

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!

LOnSLO

iTrader: (15)

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.

romanss

iTrader: (3)

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

Turo

iTrader: (23)

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

matts22

iTrader: (2)

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?

romanss

iTrader: (3)

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)

romanss

iTrader: (3)

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

Colonel

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.

rons 00z

iTrader: (10)

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

JL ws-6

iTrader: (50)

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?

romanss

iTrader: (3)

Yup, I keep on forgetting that important info.

Thanks.

Roman

romanss

iTrader: (3)

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

NOZR1

iTrader: (5)

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.

matts22

iTrader: (2)

ttt....anyone else?

matts22

iTrader: (2)

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!

2MuchRiceMakesMeSick

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

1fastWS6

iTrader: (3)

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