What exactly breaks in the stock rearend?

**LS1POWER** · 10-01-2005, 12:45 PM

I was wondering what part of the stock rearend breaks. If you got new strong axles eaton posi and richmond gears. would this rearend still break when the car is runnning mid 11s.

**kmaro** · 10-01-2005, 06:04 PM

from my own personal experience, the ring and pinion are the weakest link. i have broke two sets now ,gm and richmond.

**needmorepwr** · 10-01-2005, 07:48 PM

I broke the spider gears inside the carrier. Big bang and no more driving!

**02z28ls1** · 10-01-2005, 07:56 PM

Originally Posted by LS1POWER

I was wondering what part of the stock rearend breaks. If you got new strong axles eaton posi and richmond gears. would this rearend still break when the car is runnning mid 11s.

As I understand it from what others have been saying-the auto tranny is not as hard on the rear end-the stick shift car shocks the driveline harder.Depends on how hard you drive the car.

**needmorepwr** · 10-01-2005, 07:59 PM

Very true. The 6 speed cars are harder on the rearend if you do high rpm launches and bang through the gears like me!

Dayak · 10-06-2005, 12:45 PM

I have a 12 bolt and it is whining like crazy so I think it is going out I get a buzz and whine at the same time it only does it when u have it going forward I mean when in the gas if coasting u can't hear it ... is this bearings?? ring and pinion?>??

Dayak

**BIG D's SS** · 10-06-2005, 12:47 PM

Sounds like it is not set up right. It sounds like it is the backlash not set correctly. I could be wrong, but in my experience that what I would say.

Dayak · 10-06-2005, 12:54 PM

Hey well I would have to think thats not it cause it just started the noise I have a stroker engine and new dual friction clutch and fly wheel so thats stuff is new so unless its the drive line or something???

also Big D. what do u think would be the best moves to get this thing to get some traction>>>??

Thanks
Dayak

**Prewett** · 10-10-2005, 12:28 PM

Dayak,

had the same whinning in mine. Busted bearings were the culprit. Replaced with 3.73 gears and all is great now!

reed98 · 10-10-2005, 03:02 PM

i've set up alot of rearends, the part that gives and causes things to break is the crush sleeve, when u get on it some times the sleeve crushes alittle and then the pinion gear gives. if u use a solid pinion spacer that can help a lot......

**Fran D** · 10-11-2005, 02:26 PM

Originally Posted by reed98

i've set up alot of rearends, the part that gives and causes things to break is the crush sleeve, when u get on it some times the sleeve crushes alittle and then the pinion gear gives. if u use a solid pinion spacer that can help a lot......

This was actually the cause of my rear's failure (or, rather, near-failure...I got to it before ka-boom). The sleeve was pounded down by the pinion so many times (M6 car) that it had actually compressed another .010"!!! This gave the pinion such a good run at the ring gear that the left carrier bearing began to fail (loud growl at all speeds).

I should have gone with a solid spacer, but I was in too much of a hurry to get the rear back together.

Chris 96 WS6 · 10-11-2005, 03:52 PM

9/10 times the ring gear breaks. However, main bearing caps can break, and even the case can break.

**tici** · 10-26-2005, 02:47 PM

Originally Posted by reed98

i've set up alot of rearends, the part that gives and causes things to break is the crush sleeve, when u get on it some times the sleeve crushes alittle and then the pinion gear gives. if u use a solid pinion spacer that can help a lot......

Why is GM using a crush sleeve? There are a bunch of shims anyway in the diff that a "piece of pipe" and a couple more shims won't hurt...
Or is there an advantage using a crush sleeve?

**Fran D** · 10-26-2005, 03:18 PM

Originally Posted by tici

Why is GM using a crush sleeve? There are a bunch of shims anyway in the diff that a "piece of pipe" and a couple more shims won't hurt...
Or is there an advantage using a crush sleeve?

It's not so much a GM issue (I don't think they could care less) as much as it is an American Axle issue (the Tier One supplier for this rear). However, the benefits are speed of assembly, which then equals cost (a VERY important issue to GM

). You don't have to go through several trial setups that you'd need to with a solid spacer (to get the preload correct).

**tici** · 10-26-2005, 09:58 PM

Is it always better to have a solid spacer? Or is it only after a certain power level or driving style (races)?

To my understanding you have a basic spacer and add shims until the preload i correct... same as the carrier bearings?

**Fran D** · 10-27-2005, 04:36 AM

Originally Posted by tici

Is it always better to have a solid spacer? Or is it only after a certain power level or driving style (races)?

To my understanding you have a basic spacer and add shims until the preload i correct... same as the carrier bearings?

I can't see any operational detriment to running a solid spacer. It may not be needed, but I can't imagine it doing any harm. On that basis, I would conclude that it is always better or, at worst, inconsequential. If my car had originally been set up with a solid spacer, I don't think that the pinion bearing clearances would have opened up...at least, not to the extent that they did.

You are correct in your understanding of shimming and preload.

**tici** · 10-27-2005, 04:53 AM

Mh... I'm now installing a M6 instead of the crappy 4L60E and I'll have to replace the 2.73 rear end with something shorter (at least a 3.42).
I was always scared by crushing the sleeve too much and have the car on the lift during a couple of days until I get a new one. I'll probably go with a solid one.
Are they difficult to get?

**Fran D** · 10-27-2005, 05:21 AM

Originally Posted by tici

...Are they difficult to get?

Nope. Do a search on Ratech. It's like $15 or $20.

By the way, you may want to consider something a little stiffer than the 3.42s. I just threw 4.10s in my car and it really woke it up! It's a daily driver and it has been very well behaved with no noticeable change in fuel mileage. The original 3.42s in my car always felt a little wrong with regards to getting the car moving and being at the appropriate part of the curve for a given MPH. I'm not sure the 4.10s are optimum either, but it is certainly an improvement. Just something to consider.

**tici** · 10-27-2005, 07:25 AM

I was suggested to install 3.73.
WIth this ratio 6th gear is just a little longer than the 4th in the automatic and the 2.73 so mileage should be the same as now.
I'll have to see if I find it in the thick version because my carrier is a series 2. But I think it exists.
4.1 is really short!
Aren't they more delicate with an higher ratio?

**Fran D** · 10-27-2005, 08:06 AM

Originally Posted by tici

...Aren't they more delicate with an higher ratio?

Not sure what you mean by delicate. The shorter ratio results in a beefier ring and a more compact pinion. It doesn't seem that delicate from a simple observation. The pinion is only spinning 20% faster than it did before, so I can't see that being much of an issue either.

The 3.73 would be a good compromise, though. You should be able to find the thick gear. I've seen them on many of the sponsor sites. I think you will be pleased with the extra ~10%.