strange or moser 12 bolt?

**bpopham22** · 08-24-2010, 02:42 PM

im about a month away from investing into a new rear end and i want to know from people who have them, which is best. Strength is a big concern because the car will be procharged by this time next summer. But im also concerned about driveability, i want the ride to be as close to OEM as possible, if that is possible. The car will have around 500 rwhp and will not be raced at the track but maybe once a yr

**Supershafts** · 08-24-2010, 05:27 PM

12 bolt will handle twice that 500hp and the dana will do more then the 12 bolt...

**xmarkx** · 08-24-2010, 07:41 PM

strange has a better rep but can be more expensive depending what options you pick

**pajeff02** · 08-25-2010, 06:40 PM

Of the primary three rears... greatest to least

Strength:

Dana > 9" > 12 bolt

Weight:

Dana > 9" > 12 bolt

Efficiency:

12 bolt > Dana > 9"

I have a Moser 12 bolt in our car with 3.73's, True Trac, 33 spline axles, welded sway bar brackets, relocation brackets and 4 channel. Just a little bit of noise now under light cruise around 1,500 rpm that is lessening as we put more miles on it. Total cost was $2,800. Install is detailed in this thread: 12 bolt install

**TA98** · 08-25-2010, 06:45 PM

^^^^ have you had any leaks? i know you got yours recently and ive heard people were having problems with their rear ends recently which has me a little worried about buying a Moser

**pajeff02** · 08-25-2010, 06:53 PM

Originally Posted by T/A98

^^^^ have you had any leaks? i know you got yours recently and ive heard people were having problems with their rear ends recently which has me a little worried about buying a Moser

I thought I had a pinion seal leak after I first installed it, but it must have been excess oil from the assembly process. After a little more than 750 miles everything is bone dry.

**INMY01TA** · 09-03-2010, 07:12 PM

Originally Posted by Supershafts

12 bolt will handle twice that 500hp and the dana will do more then the 12 bolt...

Heh. I'm the owner of a Strange 12 bolt and I've seen at around 7 or 8 guys in my club break 12 bolts with less than 500hp through the years. Mine is still good tho.

**Mr. Luos** · 09-03-2010, 09:06 PM

Is the 12 bolt the only option???
If so, go Strange.
And NOT Moser.

I recommend Midwest 9" rears.

**Supershafts** · 09-04-2010, 05:17 AM

Originally Posted by INMY01TA

Heh. I'm the owner of a Strange 12 bolt and I've seen at around 7 or 8 guys in my club break 12 bolts with less than 500hp through the years. Mine is still good tho.

I have repaired almost every diff there is
.....
Any diff will break if you don't know what you are doing and use it improperly....
Breaking a 12 bolt with less then 500 hp means someone was just keeping their foot down when they had wheel hop, tire shake, or some other issue.
The same will happen to any rear/diff doing the same thing...

Example.... Kid comes in (he has a AAM 14 bolt) with his jeep... see's me re-doing a torn up AAM, he says i thought these were indestructible, i put one in my jeep.
I told him that this jeep owner thought the same exact thing, and he thought that meant he could go rock climbing like you and no matter what he can keep is right foot firmly placed against that right pedal on the floor....
This is what happens to a diff when you do that.

That is what happens to any diff AAM, Dana, Sterling, BW, ect...

I would replace the rear in this order and go 12 bolt, Dana and then 9"... in that order..

.

**SHovV** · 09-04-2010, 08:26 AM

automatic, get a 12 bolt
manual, get a 9"

**Firebirdjones** · 09-04-2010, 11:48 AM

Supershafts is correct. If you are breaking a 12 bolt, there are other issues going on. Either the rearend was not setup properly to begin with or you have other drivetrain issues that need to be addressed.
I've built many 12 bolts over the years and run them in 3 of my own cars. Most of them behind 10 second cars without a single complaint.
My chevelle came factory equipped with a GM 12 bolt, and since I've had the car (1987) I went through the rear in 88, still 30 spline axles, Moroso posi, Richmond gears, That's it, still a stock cover (no bearing cap supports) and stock cast iron caps.
I've raced it with that same old 12 bolt. 1.5 60 foot times carrying the left front wheel in a 4,100 lbs. car and it hasn't so much as wimpered. And that's with stock stuff.

These aftermarket cast 12 bolts are much stronger than the GM units with more material cast around the bearing supports and thicker webbing throughout. They are a great piece if setup correctly.

**TmaxicanA** · 09-04-2010, 02:48 PM

this is a great thread. i have been looking at rear diffs for awhile. and thought moser 9" was the only way to go lol. thanks for all this info

(not my thread but i appriciate it none the less.

**INMY01TA** · 09-04-2010, 03:02 PM

Originally Posted by Supershafts

Breaking a 12 bolt with less then 500 hp means someone was just keeping their foot down when they had wheel hop, tire shake, or some other issue.
The same will happen to any rear/diff doing the same thing...

Nope every one of em broke right off the line. Wheel hop and tire shake is not a problem with these cars at those power levels. Usually the Eaton posi is what broke in em. I do have several friends w/12 bolts running spools and they hold up just fine.

Originally Posted by firebirdjones

I've built many 12 bolts over the years and run them in 3 of my own cars. Most of them behind 10 second cars without a single complaint.
My chevelle came factory equipped with a GM 12 bolt, and since I've had the car (1987) I went through the rear in 88, still 30 spline axles, Moroso posi, Richmond gears, That's it, still a stock cover (no bearing cap supports) and stock cast iron caps.
I've raced it with that same old 12 bolt. 1.5 60 foot times carrying the left front wheel in a 4,100 lbs. car and it hasn't so much as wimpered. And that's with stock stuff.

Read up over on LS1tech. The 12 bolts they make for the 4th gens with torque arm mounts just don't hold up the way the ones of yesteryear do. I know, everyone I know near here and on tech just doesn't know what they're doing.

**Packy** · 09-04-2010, 04:16 PM

My Moser 12 bolt has been in my car for 8 years with no issues. I have broke a torque arm but the rear end had no problems. I even ran a six speed for about 5 of those years. I just wish that I would have painted it before I had installed it.

**Supershafts** · 09-05-2010, 11:52 AM

Originally Posted by INMY01TA

Nope every one of em broke right off the line. Wheel hop and tire shake is not a problem with these cars at those power levels. Usually the Eaton posi is what broke in em. I do have several friends w/12 bolts running spools and they hold up just fine.

Read up over on LS1tech. The 12 bolts they make for the 4th gens with torque arm mounts just don't hold up the way the ones of yesteryear do. I know, everyone I know near here and on tech just doesn't know what they're doing.

What broke in the eaton ? Was it really an eaton or some bs china copy...
I know a lot of you have no idea probably...but YOU better make sure and DEMAND no china copies of anything in your stuff when you buy it....

Many respected, wait, better advertised aftermarket companies are using china copies...

I have seen the billet input shafts china copies...... torque converters, china copies.... rear end parts of every piece, china copies...... driveshaft stuff, china copies.....
So when you have a friend who broke a eaton......the only thing eaton about that part might have been the name on the box..

Get me a link to the thread

Firebirdjones is right the new stuff the aftermarket is making is much better as per strength... just becareful they aren't taking the padding there pockets approach
Even the drop out 3rd section 12 bolt is stronger....

**Firebirdjones** · 09-05-2010, 12:14 PM

Originally Posted by INMY01TA

Nope every one of em broke right off the line. Wheel hop and tire shake is not a problem with these cars at those power levels. Usually the Eaton posi is what broke in em. I do have several friends w/12 bolts running spools and they hold up just fine.

Read up over on LS1tech. The 12 bolts they make for the 4th gens with torque arm mounts just don't hold up the way the ones of yesteryear do. I know, everyone I know near here and on tech just doesn't know what they're doing.

I've run nothing but the Eaton posi's in my builds, run the Moroso version in my own, never had problems with either on cars making 700+ HP.
My Moroso is only a 30 spline version too. I use the new Eaton 33 spline versions in other builds, one of if not the best posi on the market as far as I'm concerned. Eaton was the supplier for GM throughout the muscle car wars.
Don't care much what anyone says over on LS1tech. You need to talk to Strange personally, they'll give you all the details on why they like the 12 bolt torque arm setups over the 9 inch setups. I doubt anything I tell ya will matter.

**Firebirdjones** · 09-05-2010, 12:19 PM

Originally Posted by Supershafts

What broke in the eaton ? Was it really an eaton or some bs china copy...
I know a lot of you have no idea probably...but YOU better make sure and DEMAND no china copies of anything in your stuff when you buy it....

Many respected, wait, better advertised aftermarket companies are using china copies...

I have seen the billet input shafts china copies...... torque converters, china copies.... rear end parts of every piece, china copies...... driveshaft stuff, china copies.....
So when you have a friend who broke a eaton......the only thing eaton about that part might have been the name on the box..

Get me a link to the thread

Firebirdjones is right the new stuff the aftermarket is making is much better as per strength... just becareful they aren't taking the padding there pockets approach
Even the drop out 3rd section 12 bolt is stronger....

Exactly, you have to watch what ya buy. Everyone searches the internet for the best deal only to get china made crap in a name brand box. Not the best approach.
Like I mentioned above, I haven't been able to break an Eaton posi with over 700 HP. You can get them with up to 33 spline axles now, enough to support well over 1,000 HP and TQ.
I agree, if people were breaking them, it was china made crap in an Eaton box.

**Mr. Luos** · 09-05-2010, 12:21 PM

My biggest problem with the 12 bolt is how the torque arm mounts to it.
Seems it would be a stressing point.

I like how it connects to the 9". If it bends or breaks...the whole housing isn't shot.

**Firebirdjones** · 09-05-2010, 12:24 PM

It's not any different than the 10bolts everyone is pulling out. Actually, if you look at the aftermarket cast 12 bolts closely you'll notice they have much more casting in this area for strength than GM ever designed into the 10 bolts.
I've used the Currie torque arm bracket that adapts to any 9 inch housing. It uses 2 of the studs that hold the third member in place, and if I remember right, there are some tack welds to be made on the housing itself.
It's a good piece, but I don't see in any way how it would be better than a cast iron 12 bolt housing that has the mounts cast into it all as part of the housing. Personally I've never had an issue with either one way or the other.

**Mr. Luos** · 09-05-2010, 12:27 PM

Even just a tweak can effect the whole rearend.
Similar to why donuts can kill a 10 bolt.

Granted, it isn't likely.

Personally....Midwest Fab 9" and be done with it.