mike02ss

I am wanting to put in a rearend in my car and somehow can't make a decision. I like the 9" but was told my a reputable company that it is not the ideal decision for a daily driver due to the housing sometimes making contact with the floor pan on corners or bumps. Those with a 9" please tell me your experiences. Also would you buy a strange over a moser and why? Anyone with a 12bolt with the 3.90 axle ratio please tell me if it makes a lot of noise. Thanks

Silver Slayer

iTrader: (13)

I have a 9" in my daily driver. The issues I had from Moser were:

1. The axles were too long. I had to cut both of them.

2. The torque arm mount on the housing had to be ground down to allow my sway bar to bolt up.

3. The side bolts for the BMR torque arm were rubbing against the side of the tranmission tunnel.

4. Gear setup from Moser sucks! I sent my third member back twice to have them set up the gears and replace the pinion seal.

5. Do not get the Auburn Pro Series posi unit if you are planning to take it to the strip. I even sent mine back to Auburn to have it replaced under warranty, but the first time to the track and it would not turn the left rear over in the water.

Other than that, I have had no problems. Just have someone that knows what they are doing check the gear setup prior to installing. My main decision in choosing the 9" was the brute strength and accessibility to the gears. I can take the third member out and do gear changes on a bench instead of laying under the car. I also have the 3.89 gears and I am very pleased.

I do not regret my decision on the 9".

Any other questions let me know.

Kevin

ShadowZ28

I ordered an 8.8 and am waiting for it to come in. I'll let you know how it is when it comes in.

Joe

TTPMatt

iTrader: (18)

The 9" is not a 'direct' bolt-in as Silver Slayer said. Unfortunately the pinion angle is greatly affected on these units. The t/q arm mount is not an exact science and it also depends on what torque arm you have (Obviously an adjustable t/q arm would be a better choice for a 9").

The Moser 12-bolts (Eaton Posi) we have in cars have seen 500-600rwhp with absolutely no problem. The 12-bolt is also lighter and less rotational weight = less paradistic loss (Drivetrain loss).

The only 'problem' with the 3.90 gear ratio is that they are Richmond gears instead of Moser US gears, and they tend to be whinier than any other gears. Richmond makes a good set of gears, however they can tend to be loud. In some cases they are quiet, but in others they are loud so it's all luck of the draw unfortunately. Of course, the setup on the gears has an impact on the noise. If you can go with a 3.73 or 4.11 they should be quieter, however if you can deal with some noise the 3.90 is a good choice.

What modifications do you have/plan to have in the future? Automatic or manual tranny?

We are the largest vendor on the east coast for Moser 12-bolts in 4th gen f-bodies. Give me a call and I'll be happy to discuss anything you want to talk about. We are running a great sale on these right now until 12/31.

- Matt

mike02ss

Thanks for the replies, Matt does moser make a completer bolt in rearend? Car is a 2002 with abs and tcs. I want the rearend with the least amount of hassles, just want to basically do a swap. Thanks..

BLKWS6

My Moser 12bolt with the HD eaton unit w/3.73s broke after 6 passes. And of course, moser doesnt care. not bad, $2300 for 6 passes..comes out to about $383 a pass!
Had it a total of about month and a half. Best 60ft was a 1.71.

mike02ss

BLKWS6 thats the reason I can't decide which rear to buy, I want to buy the best and not have any issues. It seems all 12bolts have some kind of problems while the 9" has bolt in issues. It really sucks that manufacturers can't make a product to perform at the level of which it was intended, and after they get your money you're on your own. Still undecided

1ScrudeDude

This **** scares me. I'm scraping hard to get my cash together, and this is not encouraging. Moser needs to do something about their customer service and warranty.

I too, am the deer frozen in headlights, not knowing which way to go withthis damn rear end thing....

pontiac

iTrader: (4)

I just blew up my 10 bolt 4 10 rear end and replaced it with a Moser 9" housing. Moser 31 spline axles (you can find all kinds of 31 spline **** out there cheap) with a Detoit locker. Mine bolted in perfect. The traction control sensur was a pain in the *** but you would have had the same pain in the *** on a 12 bolt. brackes traction controle both work great drives great you can tell the rear end is tite and not going to break. i have a second chunk with a miny spool and a 4.56 gear got it off ebay fo 200. i drive the 4.11 detroit locked every day and love it. hope this helps.

TTPMatt

iTrader: (18)

I've heard of only a few isolated incidents of 12-bolts blowing, all sorts of brands. The Eaton posi is a rebuildable unit.

We have had no issues so far with the 9" that we have installed, I just want to point out that I have heard issues and I'd rather you guys all know that before I say 'well they have no problems at all'.

Put it this way, we have put so many of these units out the door and on the few problems we've had (One unit came without a single wheel stud, and moser shipped a brand new set -- Another customer bent an 30 spline axle and moser replaced it when it wasn't even covered).

Customer service goes a long way in this game, I would not think that Moser would blow someone off like that.

- Matt

1ScrudeDude

So Matt, you are saying that Moser is being better about follow up and quality assurance? I don't mean that sarcastically, but if this is true, then sales will start zipping.

I'm looking hard, and want to convince myself that the Moser is the one to go with because it's cheap(er) and power efficient. But I went through the worst gear swap in history with Motive, so when I hear things about the ring/pinion set up, I cringe.

BTW Motive now stamps the ring/pinion set, so the installer can dial in the pre-run numbers. That didn't happen until after me....

Hardtop

iTrader: (3)

Matt, I'm not trying to be a pain but I know of more than a few Moser and Strange 12 bolts that have broken. They use the same Eaton posi. There is no way that either of them is going to hold up to 500-600 rwhp and a M6 for any length of time. I've got a Strange 12 bolt, so I'm speaking from experience. I have seen more than a few posi's and spyder gears do this.>>>>>> Save yourself the money and aggravation and get a 9" with a locker. I'm going to this spring.

Bruce

Silver Slayer

iTrader: (13)

I have a friend that trashed a new 12 bolt posi with only 297HP and 30? Ft Lbs on ET Streets. It was a 6 speed car though.
I will say that Moser was happy to accept my third member back twice, and told me they would keep trying till they got it right. I say that they should have been able to get it at least close the first time, considering the number of units they sell and the amount of gear setups they do. It also pisses me off to think that they did not even send the right length axles.
As far as a complete bolt it 9" I do not think Moser does that unless you send them your brake backing plates and ABS rings (if equipped). You might find a sponsor that will have the rear sent to them and then they will install the backing plates and rings (for a small fee of course). Otherwise, you will have three boxes sent to you house, you will have to install the backing plates and find someone to press on the bearings and ABS rings.

Kevin

Deeavi

iTrader: (16)

The thing on rear ends is setup. Check you setup even on new ones. Break them in right, and always warm the rear before running.

kp

iTrader: (34)

If you are going to drag race your car a lot with slicks/et streets and need a posi just get the 9"

Occasional track use and not leaving off the rev limiter a 12 bolt/posi 33 spline will hold up. I never had any problems with mine leaving from 6200+ on ET streets, I had a 3.90 gear (moser installed) in my 12 bolt and it was fairly loud from 50-70mph but nothing I would consider excessive.

But I really wasnt 100% confident in the rear either after seeing a few blow up in a fairly short time. The Moser housing is pretty stout but the spider gears in the posi is the weak link. The old brute strength moroso posi units used to hold up pretty well but they cost. Sure the eatons are rebuildable if the spider gears dont tear everything up when they shatter

A 9" just doesnt cost that much more but there are hassles sometimes with any kind of mods, pressing on the axle bearings is no big deal and thats an easy 25.00 job at any machine shop/parts store with a press. The pinion angle can be adjusted with an adjustable torque arm. If your car is lowered they do get pretty close in a couple spots and they are heavier then a 12 bolt.

In the long run the little extra work will pay off when you are sitting at the starting line after spending 2300.00 on a rear end and being 99% sure it wont brake as opposed to 50% sure. You could have just saved the money and been 25% sure with your stock rear

Probably the least hassle bolt in would be the 8.8 since it uses your factory tubes. I think its a great idea but its really not that much cheaper then a 12 bolt after its optioned out and you have to send them your old tubes or another 100.00. If you can sell your old rear for 250 or so it pretty much offsets the difference. I still consider a 8.8 but will probably go with a moser 12 bolt/spool for my next rear since I can have a moser 12 bolt to my door in a week

Its a rough decision but I really think for a heavy M6 car the only choice if you want a posi is a 9 inch. A 12 bolt with a spool is pretty indestructable also but not for an everyday car.

1ScrudeDude

I hear that 3.90 gear is loud no matter what. TByrne even discloses on his website that he doesn't think the 3.90 is an option.