I purchased my chevelle three months ago.
I has now developed a clunk sound in the rear end when turning the wheels on a jack.
Specs, 1965 chevelle zz502, th400, 12 bolt gm. It has a locker in there, anyone have any ideas ?

http://i37.photobucket.com/albums/e97/Rockern/Bakaksling013.jpg
http://i37.photobucket.com/albums/e97/Rockern/Bakaksling012.jpg

the gearset is richmond 49-0095-1 by the way, 3,55:1
and there are springs inside of it, unforunately i didn`t take any photos of the inside.

What ever it is, it is busted. Sorry.

How do you now it`s busted ?
Is it repairable or should I be ordering a new one ?

i would not say it is busted.
it is a eaton posi, which is ussually a very good unit. i would recomend atleast inspecting the internals. easy to take apart and can be a somewhat difficult to reassemble.
let us know when you are ready to check it out. all parts are available for it. tom

it may not be the problem, could be a axle bearing, ujoint or some part of the posi internals or a bearing.
take your time and check the easy stuff.
it is a eaton 2 series posi, it also has a spacer to use the 3 series gears. tom

It's hard to tell from the pic but I don't see anything that looks broken, It looks like a stock GM carrier-you say it has springs in it -then it would be a posi, if it has 12 bolts holding the ring gear on it's a 12 bolt GM. As for the clucking sound, all rear ends will make a slight cluncking with no gear oil in the case, it's the backlash between the gears. If your pinion gear isn't wobbly ( up and down ) and the gears don't show any galling ( which it doesn't look like they do in your pic ) and if you don't notice it when driving your probably OK. The only other thing would be the clutches in the posi are worn out which would cause a noise when turning or the bearings would be shot which would make a noise when driving that you would definitely notice. If there is alot ( more than a 1/4 in. or so at the yoke ) of free movement in the pinion gear when you turn it back and forth while holding the ring gear still your pinion nut may have backed off allowing to much back lash but it's hard to tell that from a picture.

MrBreez

Here are two videos, maybe they`ll give a better description ?
Poor filming though as I`m holding the camera in my mouth while turing the wheel haha.
YouTube - GM 12 bolt eaton posi, what is wrong ?
YouTube - GM 12 bolt eaton posi, what is wrong ? NR2


Does this look normal ?

It sure looks busted to me in that second pic. That crack lookin' deal that runs up to the cross shaft bore on both sides is just a little noticeable. ;)

That sure looks like a crack to me!

that is why I said it's busted, after 43 years in the repair business, I think I know a busted center section.

Ditto by me too, it looks to be a heck of a crack and I'm NO rearend guy at all..

I have a feeling it's going to come apart just like an egg.

pdq67

These cracks :(

of course !!(""/&!&!!!! how could I have overlooked that crack ?!?! I was focusing on the internals and the gears. :-(
Good thing i found what was causing the shaking in my car.
Stupid thing is that I was planning to take the car for a 650 mile ride this weekend and I`ve been looking forward to that trip for 3 months !!!

Would I be crazy to weld it together an drive carefully ? I friend of mine is a good welder and could help me with it..

it sounds like to me that the pinion is mess up , i cant imagen how that could happen, tell what where you doing when it started to make this noise, was you doing a burn out , the fuild looks clean, just rip that bad boy apart , to easy and you will see it for sure, check the outer bearings normally that where your failure will begin, if it was low on fuild , thats what i would do, these rearends are not complicated, pull your c clip and remove your axels then remove the four bolts and pull the third member, just keep the shims left and right seperate, your going have to put it back to , then take some pictures also where the sound coming from the center or the sides

NO, You need a new carrier. No welding, no repair, just buy a new one, and have the rear re-set.

I`ve been doing burnouts all the time ;-) the sound has been coming gradually the last week. been taking it easy but that`s easier said than done..
Don`t know if I have the time to fix this one before we leave though. Might be taking the 2.gen camaro wich is soo sweet too and will handle the trip too. but I was soo looking forward to kill some riser on our way though.

With rough driving this is what you have to expect, and that`s ok. But the timing of this happening now couldn`t have been worse.

What`s the strongest carrier on the market, suitable for street driving ?

And thanks for all the help guys !

Get an Eaton Posi carrier, get rid of the mini spool.

Isn`t eaton what I have or is mine a stock 12 bolt posi ?

Been making some calls here and it seems like moser eaton or auburn series is the way to go. Kind of hard to know the difference between the two. But it seems like auburn is the strongest one, wich is what I`m after know. Anyone have experience with these units?

But it seems like auburn is the strongest one


l:)

I must have been funny in a way. I have no idea about rearends, so where making some calls and this is what I got out of it. Auburn gets good words from people here in Norway. though, for street/strip applications.

Other than laughing your guts out on a newbie give me a few lines of positivity instead, I just discovered that waiting for a complete new rearend will be 6-7 weeks.

Would you go for overhauling or complete new rearend ?

Get the Eaton! Auburns are not the strongest.

Remi with you being in Norway it may make obtaining parts a bit more challenging. Most people prefer Eaton's over Auburns. The Eaton's are rebuildable unless you have catastrophic failure as you had. I would suggest if you can afford it a complete new rear from Moser. They offer them complete and with options including ford style axle bearing which are stronger than the factory C Clip style axle set up. I believe I have read where they have also relocated the upper control arm locations correcting some geometry issues. Good luck but as I said earlier some, including myself didn't realize your location. Here in the states you can have a new unit or rebuild parts in your hands in a day or 2 and most would just rebuild it.

Hi Rokker I´m from Sweden over here Auburn has bad reputation. Try if Stig at Stigs Axle and parts(0121-30125) he use to has Eaton in stock. If you plan to visit the strip often maybe you should compare the price for rebuild/upgrade yours vs a complete Moser with ford ends(here in Swden c-clips are totally forbidden on the strip). Used 12 bolts are valuable in Sweden guess Norway to? Heard a guy who gave as much as 7000 skr for an open chevelle 12 bolt, I bought two opens one for 5000 and the other for 4000 skr. Think a Moser is around 2000 us$+freight do not know how custom and taxes work in Norway.

Marcus

I`m considering a complete rear end from Moser. Where would be the best place to buy it? They sell it here in Norway tot but it is about 7000usd from the store. I would rather by it directly from Moser if that`s possible. Any other good plasec to buy it ?

If I could get one for 2000usd that would be the way to go for me. Either 12bolt or 9" haven`t decided.
Since mine is blown and I need a new carrier I would like to get new gears and axles too while I`m at it. And that rebuild is 3-4 weeks and about 3000usd here in Norway..

I`ll be checking out Stigs Axle tomorrow too.

I really think you can replace your broken differential with a new Eaton posi for way less money. A new Eaton posi would run you about $400 - $450 here in the states, and labor to install probably another $300. If I understand correctly, you already have a 12-bolt, so the Moser assembly would offer little additional benefit.

I agree with you Georgia69, the thing is that while It`s open it I`d like new gears as well, the 3,55:1 is too low for me. I`d like 3,.08:1.
And as I mentioned earlier together with new shafts and labour wich is 700usd here in Norway I`m getting pretty close to buying a new moser 9" rear end. And if it saves me some time too it`s hard not to consider it.

And I could probably sell the broken 12 bolt too for some Norwegian krones.

Don't do the 3:08's, I switched to Them, and switched back to 3:31. The 3:08's are to high, and will affect the performance.

Are You running a 5-speed, or TH400?

There is a Norwegian here in the PNW, goes by ejhorton, He might know some import regulation's for shipping to the Homeland.

Imho, 3.31's are GREAT!!

Best overall compromise of tire spinning and running the hwy's!

Short wide drag tire for the strip and a tall skinny tire for the road!

Best of both worlds unless you want to buy a 9" and two pumpkins, one a 3.00 and the other, a 4.11! I bet that even old man like myself can R&R a 9" pumpkin in like an hour and a half at the strip!

pdq67

as I`m holding the camera in my mouth while turing the wheel


unnhhhh....got any pictures of that?

I`m running a Th400, but a MUNCIE is lying on the shelf and it`s going in there after a while.

3,31:1 might be the way to go then. I would like lower cruising rpm, and it seems to little, but haven`t tried changing rear end ratio before so it`s hard to now if I will even notice a switch from 3,55 to 3,31.

Should i get the moser axle from moser itself ?

Am I breaking some rules here on the forum by asking where to buy parts?
I`m waiting for shipping estimates from moser now :-)

Having a real hard time deciding for rear end gears though. I`d love to have a 3,08:1 in there for cruising BUT this car isn`t really a cruiser either. So I`m thinking if i get the 3,08:1 gears I could swap gears in my muncie, getting maybe a 3,40:1 first gear, if it`s possible in the muncies, this will will give me about the same pull in first as the 4,11:1 rearend would do with my th400. But then it becomes a big project though..

Is true trac ok?

Where I work, we use Randy's Ring and Pinion, www.ringpinion.com is the link. Good luck with your repair.

Our Muncies are only 2.56 early /2.52 later wide or 2.20 close ratio'd 1st geared!!

And imho, the BEST gears going are the 3.31's!!

And btw 12-bolts are 3.07!

And if I had the money, here is what I'd do!

I'd buy a Richmond 5-speed w/ a 3.28 to 1 1st gear and a 1 to 1 5th gear and use something like 2.73's OR the 3.07's out back!

But just be forewarned, it won't take many sidesteps at 4,500 rpm if it HOOK's behind a stout 502 that I know of??

Otherwise, look into the TKO 5-speed type tranny's..
And the next step up is the 6-speed......

pdq67

I wouldn't do 3.07's with a future planned muncie swap. Your 400 has a much lower first than a muncie. I have a M20 with a 2.52 1st and a 2.73 rear and a stout small block. Forget about keeping a single disc heavy duty clutch in the car that doesn't chatter when you HAVE to slip the hell out of it or constantly be sideways on the street! First full throttle run the clutch let loose anyway. I am swapping back to 3.31s next weekend and a Mcleod street twin clutch. 2.73s with my 700r4 were alot of fun (low first gear), 4.11s were not! The car was just violent and worthless due to spin off the line, but I didn't turn many rpms on the freeway.

I am learning that I am not an exception to the rules when it comes to gearing, before you decide your rear gear give this some thought. I will not run anything less numerically than a 3.31 if I am using a muncie 4sp. If you are using an auto you can get away with it. I agree with the others though, 3.31s are a good all around gear except you have to find a used set or go with 3.42s or 3.55s from the aftermarket. Found mine on Ebay for $160.

I am running the Lok-Right locker which is like the true-trac, from the same company. I would go with the Lok-Right if you want a mechanical locker (I love it and it isn't as undriveable as people think and isn't noisy compared to the rest of the car if you are running street tires) it is cheap and effective. An Eaton posi is a lot more user friendly and by that I mean smooth engagement/disengagement, quiet, not as hard on the rest of your drive train, and since you have to set up your gears anyway to replace a carrier might be the best option .

I wouldn't do 3.07's with a future planned muncie swap. Your 400 has a much lower first than a muncie.

Muncie has either 2,20:1 or 2;52/2,56 my th400 has a 2,48:1 wich is very close to the wide ratio Muncie. Just for the record..

Here`s the car by the way.
YouTube - Chevrolet Chevelle ZZ502
http://i37.photobucket.com/albums/e97/Rockern/165.jpg
http://i37.photobucket.com/albums/e97/Rockern/153.jpg
http://i37.photobucket.com/albums/e97/Rockern/154.jpg
http://i37.photobucket.com/albums/e97/Rockern/155.jpg

Sorry, I was thinking about the 700r4 which is like a 3. something.

Yep, that is why your rear is busted. That is what fun does.

guess who`s waiting for a new moser rear end with 3,08:1 gears ?
Not the cheapest way, but definitely the safest and best way don`t you think?! (except for the gearing which i guess most of you guys would call girlie haha)
Guess I`ll have to add a supercharger after all then... haha, and a richmond 5speed :-) LOL
Maybe in time, I`m happy with the power the zz502 makes, and guess going from 3,55:1 to 3,08:1 won`t have to dramatic results anyway. Maybe I can even start using first gear WOT without only spinning tires? that would be fun !

New carrier for sure,

Here`s a picture of the new rear end almost installed.
The 3,08 gears was kind of a bummer on the performance side though, made a bigger difference on both performance and fuel consumption than expected. Have done a few more mods too so hard to tell if the rear end gears is the BIG sinner or not. Should have stayed with 3,55 or gotten the 3,42s.
All the mods together have taken me from around 11 mpg to 14,7mpg, so can`t complain much on the fuel consumption now.
http://i37.photobucket.com/albums/e97/Rockern/Bakaksel021.jpg