New moser or build an original 12 bolt

[keith4909]

1967 Gto
474ci
Turbo 400

A recent deal I had to buy a 12 bolt off Craigslist fell through and now I am searching for another one. It would cost me 2000-2300 to build up a Chevy 12 bolt and 2700 to have a moser unit built. Any thoughts? Benefits? Disadvantages?

[parsonsj]

Does rear end noise matter to you? All the aftermarket gear sets are noisy. You can set them up perfectly and they will still make noise. If noise isn't a factor, do the 9".

If noise does matter than you need to find a rear with original OEM gears. An inexpensive way to go is buy a late model Mustang 8.8 rear. You can still get brand new Ford gear sets that are OEM quiet, and the rear itself is very strong, with lots of aftermarket support. I recently pulled a 9" inch DSE setup out of a customer's car and replaced it with an 8.8 with good success.

[keith4909]

How loud are we talking. My exhaust is loud but still want those parts to be quite

[parsonsj]

Lots and lots and lots of 9" rear ends make noise you can hear -- usually in the 40-70 mph range. Racers couldn't care less about that, but that's cruising speed for street driving.

[Spork82]

It's a weird "whurrrring " sound

I agree with Parsons, you can find a 8.8 out of any 88+ Mustang and build it. Lots of guys buy Explorer 8.8's since many of them are disc and posi but they have an offset pumpkin.

I found my mustang 8.8 on CL for $70 and installed a eaton posi, frpp gears, oem bearings, custom driveshafts and wilwoods for $1500.

Lots of parts for them and endless options for suspension setups.

[1BADBET]

Not to hijack but if you use the GM synthetic gear oil it should stop the noise. I've put it in noisy rearends from all manufactures new and old and they're always quiet. Had a buddy with a Toyota truck that had the rear end serviced and it made noise, we swapped in the gm stuff and it's dead quiet....


For the few extra bucks i would buy all new from moser. The new center section and tubes/ brackets are going to be thicker and stronger than the 50 year old stock stuff.

[Z06vet]

Synthetic fluid will not stop gear whine. In fact, the paperwork that came with my new moser 12 bolt specifically say DO NOT use synthetic fluid. Several other rear ends & center sections that were used on some builds I helped with also specified not to use synthetic as well. I know some guys that use it on track cars swear by it. My new moser whined like nothing I have ever heard. They sent me a set of new richmond gears (this was 3+ yrs ago) and they very close to 100% quiet. I had the tech use marking compound on the set installed by moser, & the pattern went right off the end of the ring gear. I wont get into that here. I have since built 5-6 cars and have been putting used GM gears in them. That has worked well for me. I would tend to try to do the same for the 9". John has much more experience than I, and I just wanted to affirm his advise. I refuse to put up with gear whine, its just not acceptable to me. Scott

[parsonsj]

I'm told that Strange Engineering announced at SEMA 2013 that they would be introducing "double-lapped" gear sets (like what the OEMs do) to reduce aftermarket gear whine. I don't know if they ever actually came to market.

[69X22]

Does rear end noise matter to you? All the aftermarket gear sets are noisy. You can set them up perfectly and they will still make noise. If noise isn't a factor, do the 9".

If noise does matter than you need to find a rear with original OEM gears. An inexpensive way to go is buy a late model Mustang 8.8 rear. You can still get brand new Ford gear sets that are OEM quiet, and the rear itself is very strong, with lots of aftermarket support. I recently pulled a 9" inch DSE setup out of a customer's car and replaced it with an 8.8 with good success.

I agree 100% with John. There is nothing worse than sinking 80k plus in a car just to hear gear whine when its done. I went through 3 sets of aftermarket gears before I put a set used OEM gears off of ebay in.

[Bonehead]

Well. Let me share a little story with you.

I've always had a 9" in my a body Chevelle/El Caminos. Always. Since I was 20, all my junk has had a 9" swapped in. When I started a 1967 El Camino I'm currently working on, I decided on yet another Moser and that was that. As the build progressed, I ran across a 12 bolt for a 67 with a 3.42 and an Eaton posi for $1000. I thought, why the heck not? Spend a grand, or spend $4000 on what I wanted from Moser. I decided to bit the bullet and get the 12 bolt. Brought it home, popped the cover, everything looks good. After 3 months of sitting I decided it was time to put it in the car. Had factory axles so I thought I'd upgrade to some Moser 30 spline and call it good. $1000 + $260. Still not bad. Then I thought, well might as well get a good cover for it and while I was at it, swap the 3.42 for a 3.31. All that with an install kit - $1000 + $260 + $160 + $250 + $120. Well that's not exactly what I had planned, but ok. Good upgrades. No worries. Welllllll.......come to find out, 12 bolts are a bit of a pain in the backside for getting a little out of wack. In other words. This on was bent. So, off to a great guy in Kent WA to have him straighten it up. Hey! While I'm there, might as well have him strip it all down, clean it, straighten it up and weld the axle tubes up. Solid. Then hey if hes gonna do that, might as well hack the ends off and put the 9" ends on since all my brake kits have the big Torino ends on them. Yup. Forget it. I'm so over the top dumb with this thing for a little more I could have just bought what I wanted in a 9" and have been done with it. Lesson learned. I'll never do another GM diff again. YMMV! Note: I pick the diff up in a week and the total cost sunk into this pile is just under $2650.

[bergers59]

Where did you get 2000-2300 from? I'm building a 12 bolt soon and I figured;
650 for axles
700 for carrier and ring gear/pinion
150 for c clip eliminators
100 for bearings/seals/gaskets
intend to put it in a car that will run low 11s on slicks
edit: I didn't include cost of housing, since I got one for free

[keith4909]

I don't have the housing and in the SF bay people are selling them for 800.00 plus

[MonzaRacer]

Hey guys if you really want some good rear ends don't overlook later Silverado 8.5 rears, swap in a non gov loc posi and make them fit length wise.
I honestly have been seeing so many places overcharge for rear ends lately. Using current housings I have been buiding rears in $1200-$1500 without exotic mods.
Lost one local welder who could weld tubes and install ends reasonable and true. If I had dedicated shop where I could wire up big welder I could do tubes and ends.
Its not rocket science after you see/help do it but does take some skill.
But I really haven't seen many new gear sets that noisy. I mean a 9in does have some gear whine but honestly I have had great success in rebuilding rear ends.
My main supplier so far has been West Coast Differentials for parts, I have been using Sierra gear ring and pinions with great success and reliability.
Still use Moser/Williams/Summers Bros for axles. Keep having Strange axles snap for some reason. I even sold few sets of Dutchman axles.
Heck if stock length Superior axles are labeled as 20%-40% stronger than OEM.m

[bergers59]

800 for a rear? jeez thats the most expensive I've heard yet. By the time you clean the housing, figure out if its straight, weld tubes, weld in c clip eliminators, you may as well buy the moser

[Skip Fix]

Moser 12 bolt center sections are beefier than stock ones.

Here a basic 12 bolt core goes for $500-800.

Lee I agree those Silverado housings are plentiful. Cut the brackets and ends off and weld on billet ends for taper bearings, toss a 30 spline posi and axles in it. Downside for his application a factory 4 link you need the cast in upper control arm setup up.

Another option if you can find one 8.5 10 bolt out of a 72 ish Buick/Olds A body. Most have bolt in axles already too.

[andrewb70]

I don't know what it means for this thread, but my 9" with Ford 4.33 gears is dead quiet.

Andrew

[parsonsj]

Yes, it's really a simple relationship: OEM gears == quiet. Aftermarket gears == noisy. Ford/GM doesn't matter. I like the 8.8 setup because you can get new Ford gears. Weld on Torino ends, use 31 spline axles, your brakes swap over, and it's almost as strong as the 9".

One word of caution: the 8.8 snout is 5/8" longer, so you will probably need a shorter driveshaft if you're swapping from the 9" to the 8.8.

[4mul8ion]

I'm told that Strange Engineering announced at SEMA 2013 that they would be introducing "double-lapped" gear sets (like what the OEMs do) to reduce aftermarket gear whine. I don't know if they ever actually came to market.

That's interesting and opens up some possibilities for me. I've been looking at Strange's and US Gear's website and googled for more information with no luck yet. I've noticed that they have added 4320 as an available gear material as well. Is there any more info you can share either here or in a PM about what you heard on the double lapped gears?

Kevin

[icemanrd19]

I've seen atleast 5 dse does 9" rear ends make noise from various different levels. From mine only making alittle noise cruising to my buddy's just being flat out loud. All cara have roughly 1000 to 4000 miles on them now. Seems as soon as you start reaching 50mph plus they make that humming noise. Gears range between 370s to 411s with the same result.

My buddies 12 bolt dse setup is dead quite.

Next step is to remove my buddy's 3rd member and mark it. Any other ideas?