In this months Chevy High Performance Moser states that a properly built 7.5" 10 bolt rear end is good for 400 REAR WHEEL HORSEPOWER!. Finally someone has stepped up and made a claim as to what the 7.5" rear can handle. I always knew with people running 11's on 7.5" rears that they were stronger than people thought. Just glad to have a quantifiable number to go with these rears. Hopefully this should end some of the "my rear isn't strong enough for my 170HP TBI Camaro, hell I just went though my 2nd rear. The 7.5 is too weak!" comments. Maybe..........

BTW, the install article in this months Chevy High Performance did have some holes in it though. First of all one does not set backlash before pinion depth. If you set backlash and then move the pinion then you change the backlash reading. Secondly, when setting the crush collar tightness you look for approx. 10-15 in-lbs of rotational force not "one spin by hand". What the heck is one spin by hand!? LMAO. Lastly, why would you run main cap studs when you have a rear end girdle with preload bolts. Granted studs will help but seems like overkill when the cover preload bolts won't let those caps go anywhere. Just some food for thought.

 

how did they come up with that number?

what i really want to know is, what sort of torque will handle, with what weight car, with what kind of traction.

 

I agree with Dewey316. I'm sure that a 7.5" 10-bolt will live a long happy life behind a 600 HP engine in a light car with street tires. The tires will fry long before enough shock torque gets transmitted through the rear to snap the axels like twigs and make the ring gear spit teeth like a 98 pound hockey player.

I simply don't believe that no breakage would be experienced with 400 HP is a typical, heavy street car running slicks. I've seen these rears grenade on stock cars run on slicks. I've seen them break in stock street cars. It all depends on how hard you drive it. I think that the 400HP claim is goign to lull a lot of people into a false sense of security.

Magazine articles on major rebuilds like a rearend or transmission often leave out a lot of important details. I would never recommend tryign to rebuild a rearend based soley on a tech article in a magazine.

 

It's always the negative people that chime in first.............

 

Negative? Not really, just realistic. I know that people want to beleive that the rear that is already in their car is tough enough for what they've got planned, but most of the time that just isn't the case with our 3rd gens. They got shafted in that department at the factory, unless they were one fo the lucky few that got a Dana 44 or the Australian 9-bolt.

I have too much experience to knwo that you can never state absolutes like "that rear won't lat one trip down the strip", but by and large the 7.5 10-bolt has a bad reputation that has been earned honestly. Run one in a high powered car with traction and you'll most likely be cursing it in short order.

 

I guess it depends on how you define high power. I run 12.91 in the 1/4 mile with slicks but that is with an auto. Softer hit obviously. I will concede that a stick will bang those rear gears pretty hard but a little common sense will go a long way. Just staging properly to take slack out of the drive train would avdert most 7.5" failures. The biggest problem is that 8 out of 10 people set up gears improperly and shouldn't even be allowed in a rear axle. When you only have 7.5" precision in ESSENTIAL!

 

I agree that setup makes a big difference in any component (engine, trans, rear, ect.). That being said, the 7.5 has several inherent weaknesses that can't be overcome.

1.) 28 spline axels are the biggest that will fit. Mustang guys had 28s from the factory and consider them to be a weak link. Axel strength comes from spline count, and the 7.5 will only accept 28s.

2.) The 7.5" ring gear is puny. Even Toyota runs an 8" ring gear.

3.) c-clips. Not a good way to retain axels. They don't often break in drag cars, but for any racing where corners are turned they are downright dangerous. C-clip eliminators are a problem in and of themselves. The bearings tend to be small and the seals prone to leaks. Weld on housing ends are the best solution, but that's a job you'll have to farm out, so the cost goes up.

Driveline components are tricky when it comes to absolute strength. For every guy that's broken a reputedly weak component (T5, 7.5" 10-bolt, ect) in a street car there's another guy that's got one in a car that runs 11s on slicks. It's impossible to make a definitive call on what the break point is, because it isn't like an engine where you can say that such and such a combonation can only make a maxium of x horsepower. It's a question of airflow, not component strength.

 

Personal experience - I had a 99 SS with 150shot of nitrous, 4.10 gears and a 6-speed. I ran an 11.70 with MT Sportsman tires. In that run I had a 1.67 60-foot time. The 7.5 is not a weak rearend. I believe it IS an unforgiving rear. I don't think you can launch at 5000rpm and expect it to last. It did handle my 495 rear wheel hp with no problems.

 

The article doesn't have anything our very own tech article doesn't have https://www.thirdgen.org/newdesign/t...nguprear.shtml , except the cap studs. The article left out the tube welding. I've heard the 400 HP figure in other places.

But that's only if modified as specified. I don't think anybody would argue you can kill a stock rear fairly easily. Most don't run it behind a manual, either (at least not regularly).

 

I'll stick to MY experience with this rear-3rd one now in 2 yrs-did all the good stuff except cap studs that has been recommeded on this site and crack/clunk went this last 7.5" this car will ever see. And it's not like I'm throwing down goobs of torque either-just 100% traction going off a 2 step convertor flashing at 3600.
IMO in a drag racing application where your going to stick all you've got, you better have more of these rears in stock cause your gonna need 'em.

 

The strongest 10 bolts are the ones that have never been touched (factory stock). When you get aftermarket parts, things fall apart.

 

Factory stock are the strongest...............ROTFLMAO!

 

I like car magazines, but let's face it: these articles SELL STUFF. The false sense of security that TKO mentions is going to make people call Moser and buy stuff for their 7.5, so of cousre they will claim big numbers....

 

Haven't seen the article, but do they say to use a crush collar still??? For a better more secure buildup a solid spacer is a ton better!!! Only way I would go IMO.

 

Ah, that's the other thing I forgot to mention this time (there was an earlier post about this mag article).

The CHP mag article continues the use of the crush sleeve. Boo, hiss...

I'll agree to some extent that they're trying to sell stuff. But, Moser isn't going to put their entire reputation on the line over 7.5"/7.625" 10-bolts.

 

What exactly does a solid bearing spacer do!? Come on man when you excelerate the pinion is pushed against the case (large bearing), so the collar has nothing to do with the bearings getting loose. Hard abuse will not effect the crush collar. What could anyone possibly do to the rear end to make the crush collar get loose anyway!. The only reason for the crush collar is to ge a controlled amount of preload with high torque levels on the pinion nut. Without the crush collar, every time you tightened the pinion nut the bearings would be way too tight!

 

The solid spacer comes with shims, so you selectively fit it for proper pinion bearing preload. Then you tighten the living dog poop out of the nut, instead of stop tightening like you do when you achieve the correct preload by way of the crush sleeve.

With a crush sleeve, once the bearings wear a little bit and all the preload goes away, there's nothing keeping the nut from backing off except for some nylon thread stuff. However, with the solid spacer, you can tighten the nut about 3 times as tight as you usually end up with when you use a crush sleeve, and the nut tightness never goes away.

 

Saying that hard abuse won't affect the crush sleeve is BS. Thats why when we pulled apart my buddies Moser after a day at the track w/ 5K clutch dumps the sleeve was more than .008 less than when we measured before the install?? That piece is meant to crush, so it will...

Yeah you torque the solid spacer to alot more than 3x. When I put my gears in w/ the crush sleeve, it says to get it right w/ the preload, back off the nut, and then put in 25 INCH pounds!!! Hell the solid spacer that I installed last weekend on my buddies 96 WS6 goes to 125 FOOT pounds!! That thing isn't coming off, thats for damn sure!!!

 

LOL, that sucker ain't coming off, thats for sure. Not sure if it was mentioned in this thread, but they said it was good for 400hp on an automatic drivetrain.

 

Well start with RB83L69.

The crush sleeve sits on the inner race of the front pinion bearing not the bearing rollers themself. If the bearings, front or rear, wear the race does not move. Hence no loss in nut tightness. The solid spacer also sits on the inner race and the same thing would happen if the bearings became excessively worn. Bearing wear is also accounted for with rotational preload being 10in-lbs higher on new bearings. Either way no solid spacer is going to keep the front bearing any more tight than the crush sleeve. The best use for a solid spacer I can see is that it keeps you from making the bearings too tight! Now thats a benefit but not a strength advantage.


Secondly Chris89GTA.

I think you are confused on the 25in-lbs. That is the turning force or preload on the bearings once the sleeve is crushed. You never back off the nut once the crush sleeve is tight and last time I used my impact to tighten a crush sleeve it had one hell of a time. That nut should be pretty tight if my Titanium impact has to struggle. Furthurmore, look in CHP this month and you will see the pinion nut being tightened with about a 4 foot breaker bar. Don't you think the nut would be tight with that long of a bar? Also, you stated your "buddy" had a Moser axle that came with a crush sleeve! I think Moser knows what they are doing with rears and your buddy does too or he would not have been confident enough to buy one. So the crush sleeve is most likely just fine. Not only that but why the hell are you taking the crush sleeve out of a new rear any way......just to measure before and after lengths? How do you know you didn't mess up bearing preload or crush the collar .008 too much yourself when retightening the nut............


Not trying to be a jerk but solid spacers are not popular with aftermarket rear manufacturers and I believe that anything that could help they would use.

 

{insert loud obnoxious buzzer here}

The crush sleeve gets crushed between the inner race of the pinion head bearing, and a step on the shaft of the pinion.

When you build a rear end, you tighten the nut; when the nut first contacts the inner race of the bearing, it pushes the bearing down onto the pinion shaft; when the bearing gets pushed far enough, it contacts the crush sleeve. At that point, the bearing still needs to get pushed down another 1/8" or so in order to take all the play out of the bearings; but in order to do so, the sleeve must crush. Once the sleeve has crushed far enough to take up all the play in the pinion bearings, you continue to tighten the nut, which adds preload to the pinion bearings. At that point you have to stop tightening the nut. In my experience of actually building rear ends, such as the one I drove from Cincinnati to Cleveland on Tuesday and back again yesterday, it usually takes about 50-60 ft-lbs on the nut to reach spec preload; compared to the much higher torque you (or at least I) can put on the nut with a solid spacer. The purpose of the spacer isn't to keep the bearings tight; it's to keep the nut tight. It keeps the nut from backing off.

The reason they're not popular with rear end mfrs is because using one adds a good solid hour to the build time of a rear end, maybe more. Time is money. Yerbasic street stroke will buy his rear from the cheapest place he can get it, witness the number of people who post on this site about how they're going to the junkyard to get the rear out of a F*rd Granada or whatever and weld a bunch of stuff on it and come up with something they think is just as good as a Moser or Strange or Currie. The average customer will simply not pay the extra cost for that extra part and labor. Those that will, will specify it as part of their custom rear; rather than buying their rear on the low bid. We are relatively few compared to the low-bidders.

Please don't try to tell me what one does or doesn't do, until you understand how it works, and maybe have used one a time or 2.

 

Yep, crush collars suck. Just the idea of a crimp nut and crush collar holding my pinion in seems real hokey to me. Dana's don't use 'em, and I'm sure that it must be for some good reason.

 

I am sorry to confuse you 83 but when I said bearings I mean plural to mean multiple rear ends or all modern solid axle designs. I will edit my post to help you out.

 

BTW 83 I wasn't trying to be a dick but if it's going to be so personal then maybe your not so sure of you own explanaiton.

Even if my explanaiton was wrong it would not affect the basis of my earlier post. Same thing still applies. Crush collar would not let the bearings loosen up. Plenty of torque on JUST THE FRONT BEARING. Let me know if I got that last part right. I wouldn't want to have one thing wrong so you could make an *** of me because no one ever makes a mistake.

Also, your trying to tell us that someone who spends 1700 dollars on a perofmance rear will not pay a little extra for a solid spacer is the mentality of a performance rear manufacturer. Hmmmm...

 

Pasky, I don't see where the automatic refference is located. What page? On page 102 the last paragraph does not mention that an auto is a requirement to the 400 HP.

 

The reason that it was pulled apart before and after Mike is b/c my buddy is extremely thorough w/ his parts. He pulls everythign apart and makes sure its right spec wise before running it. He just pulled his new 383 LT1 motor apart to check clearances, torque specs, b/c he wants to be 100% positive it is right before the headache of something breaking...

As for the 25 in/lbs, you are right, I did get confused, but please don't tell me that I don't know what I am doing, consideirng I have done quite a few rear end rebuilds, and gear installs that have had absolutly no problems at all..

NOt trying to be a dick, but just saying...:lala:

 

Hmmm, your right, could have sworn I saw it said auto.

 

OK i need to start off on a new foot here. The problem with the web is that no one can tell the context of what anyone is saying. I just get excited about this kind of stuff and I really want people to see a fresh perspective. So I probably come off wrong. The input 83 has given me is fantastic, I never would have thought of being able to tighten the pinion nut even more tight than usual. I didn't mean to offend anyone and I am sorry if I did.

 

Mike its all good man. I think you are right, and the context, and sometimes exactly what people are saying and meaning can get screwed up over the web. The 10 bolt build is a great thing for us to know about. Especially if it keeps guy from having to get a Moser or Strange for a while!!!

 

The way the whole pinion bearing system works is a bit confusing. Let's do a thought exercise to clear it up.

Go look at a front wheel bearing, and imagine the following changes:

1. The rotor sits still, and the spindle spins; and

2. The nut that tightens down, instead of just being able to tighten it as much as you want, eventually runs the bearing into something along the spindle that stops it from tightening.

That's exactly how pinion bearings and crush sleeves work.

Think about the force that the castle nut puts on that outer bearing. It's pressing it down into its race. But at the same time, it's also pulling the inner bearing toward it, into its race too. In other words, whatever preload it applies, gets applied equally and in balance, to both inner and outer bearings.

Now thing about how the nut is retained in a front wheel situation. You tighten the nut and take out play; as you tighten, eventually all the play is gone; you tighten it up a bit more until you get a bit of preload; and you lock the nut in place with a cotter pin.

The cotter pin works OK there because the direction of motion is almost always the same and there's no real force on any of those parts trying to turn anything. However, the rear end isn't like that; it mostly spins only one way, but sometimes the force is from the engine trying to speed up the drive shaft, and sometimes it's the other way. So the nut is getting a tendency to be turned one way, then the other, then back, over and over again, from pressing on the yoke, which can move a little bit. Sooner or later it's going to try to work the nut loose. One of the common failure modes back in the ancient days when they actually used cotter pins on pinion nuts, was the cotter pin cutting through, and the nut backing off. As one that has had that happen to me on old rear ends, I can tell you, it sucks. Basically the cotter pin breaks; and before you know what happened, the pinion gets sucked into the rear when you go to back up, and the rear gets destroyed.

So a new retention method needed to be invented. Remember, this still has to be suitable for mass production; always keep that in mind. That means minimum assembly labor time.

So go back to the wheel bearing. Imagine that we put a step on the spindle, and put this crushable sleeve that goes between the inner race of the outer wheel bearing and the step. Now, if we choose the sleeve to require an appropriate level of force to crush it, we can tighten the nut to take up the play, but instead, sometime before the play goes away, the bearing will contact the crush sleeve, and the nut will become very much harder to tighten further, because in order to do so, it has to crush the sleeve. So, we tighten and tighten, and eventually the play is gone; and we tighten a bit more, until we get the preload we want; and the nut in theory is held in place by the pressure of the sleeve. We still have bearing preload, and it's still equally appoied to both bearings.

But there's still a problem. Anything that happens to that sleeve that crushes it some more, will take holding tension off the nut, allowing it to back off. So we still don't quite have a stable system. Much better suited than a cotter pin to being a moving part maybe, but still less than perfect. And, when a large force is applied in reverse (as shock loading does.... the parts are not smoothly pressed one way, but rather jump back and forth violently) that reverse force tries to crush the sleeve, which brings the undesired result.

Now imagine that instead of the crush sleeve, we select a spacer of a height such that when we tighten the nut down on the bearing, and the bearing reaches the spacer (and can go no farther), we have the preload we want. Now we can tighten that nut until it begs for mercy, and it will never back off. We still have preload distributed equally on both bearings (since it's impossible for it not to be), except that now we have a permanently stable nut. And, more importantly, now it doesn't matter if we shock the system, because everything is locked solidly in place, with nothing that can bend or otherwise change size or shape.

Only problem is, it costs more - ALOT more - to produce. That's a real issue in a for-profit company.

Maybe you're like me, in that if you decide that you want a certain level of perfection in some detail of your car, you will spare no expense to make it just so. And if so, I urge you to make this upgrade to your rear the next time you're R&Ring the gears. But I dare you to go through all the posts you can find on this site about aftermarket rears and find even one asking if they should get that option on their Currie 12-bolt or whatever; and compare that to the number of "Where can I get a F*rd 9" the cheapest?" type of posts.

And I also apologize for jumping on you so hard; it just bothers me to see technically incorrect information posted here, and blatantly bogus arguments contrary to established fact. That sort of thing is in the same class as arguing that the Earth is flat, and telling people that they can't sail west to get to China; when anyone that has actual sailing experience and has done it knows that you can. It just makes the arguer look stupid, while confusing the daylights out of readers who maybe don't already know the facts, but rather came here to get informed and de-mystified.

 

Great post RB!!!

 

But ultimately my point is that the solid spacer may prevent a problem but really does not enhance the strength of the rear. I don't feel that the info I have given is incorrect. In fact I feel that it is well thought out.

I'm sorry we see things so differently.

 

No need to be sorry. Its just my opinons that if you remove a chance for that sleeve to crush itself some under heavy loads, then you are making it stronger IMO... not the gears, but the setup. Now the crushing problem might not snap the setup immediately, but it will cause issues if that nut starts to come off. Just my $.02, and others might disagree.

This has been a pretty good discussion though...

 

by pulling it out of their ***.

you cannot accuratly rate the strength or life of a rear end in horsepower. peroid.




CamaroMike. give me a 170hp TBI camaro, slicks and a manual with a good clutch, and i'll break 10bolts for you.

it may take me a week, but it will break within a month. id bet money on it.

 

Thanks Chris, it's always good to get the real facts out in the open. It's important to do that since people come here to get the real deal about their cars, instead of just hearing the same monkey-spank they can pick up in the McDonalds parking lot on Saturday night, repeated by others with no experience, just regurgitating the same tired old myths that we all love to laugh at. It's amazing to me in this hobby, if a magazine prints something, or enough people say it to each other over and over again, how the most bizarre stuff can get accepted as truth. "I think" or "I heard" or "They all say" doesn't make something true.

I used to live in Tennessee. For a period of some years right around the same time as the Scopes monkey trial, there was a state law banning the use of any number other than 3 as pi; because the Bible says in the Old Testament that a wagon wheel travels about three times as far in one revolution as the distance across it ..... which of course is the definition of pi. Needless to say, it would be pretty hard to build anything round and have it come out right, if you put 3 into an equation where pi belongs. But, that didn't stop them from making the law. This sort of "I believe" and "I think" stuff we see on here all the time is just about as funny as that, when compared to reality. What somebody "believes" or "thinks" doesn't change fact. Those are the people that I always hope are in the other lane at the track.

 

I always though a good scientific method of proof started with a THEORY. If people didn't say "I believe or I think" where would we be. Also, be carefull what you say is "fact". That can always change with the next "scientific investigation".

I'm just sayin Keep an OPEN mind.

 

RB83L69
"The crush sleeve gets crushed between the inner race of the pinion head bearing, and a step on the shaft of the pinion."

Not to be a kill joy but please look at the link below.

http://www.hotrod.com/techarticles/84118/

About halfway down the page HotRod shows a pinion with a crush sleeve that goes between the two bearings. Our rears most likely don't do this due to how small the pinion is. Just goes to show you there are no absolute rules.

 

Your link clearly shows the sleeve on the step on the pinion shaft.

http://www.chevyhiperformance.com/te...148_0207_bolt/

Same thing for a 10-bolt.

 

I do agree that the 10bolt has a step just like pinion in the link you posted but.........

Don't mistake the machined surface for the rear bearing as a step. Please read the caption.

See below.


"Once you know which shim is necessary, have a new bearing pressed onto the pinion, making sure to slip the shim on first. The arrow shows the crush sleeve, which is centered between the two pinion bearings. When the pinion nut is tightened, the bearings sandwich and slightly crush the sleeve, and the tension in the sleeve provides preload on the bearings. The more the nut is tightened, the more the bearings compress the sleeve, providing more preload."

 

How has this topic gone to other rear ends now?? The topic was to discuss the 10 bolt, not other types etc., so that was the information provided. And like linked, and awknowleged by Mike, the sleeve on the 10 bolt does sit on the pinion ledge, and from there to the rear pinion bearing...

 

BWAHAHAHAHAHAHAHA!!!! Magazine articles!!!! "Our rears most likely don't do this"!!!!! That's great! You're a comedian. Just listen to you. Why, you're ready to quit your day job.

You really should quit reading magazines and actually go learn something! Quit arguing with people that know what they're talking about based on rtheir eal-world hands-on experience, thinking you know everything there is to know because you read a magazine article once.

"It's better to be merely thought a fool, than to open you mouth and remove all doubt."

OK, enough of all that. Back to REALITY. Here's a 10-bolt pinion with a crush sleeve. Obviously you've never even seen one, let alone actually worked on one, so I'll show you what one looks like. Note the step on the gear that the crush sleeve sits on. As you can clearly see from the pic, the crush sleeve will slide down the pinion until it seats on that step, and that's what crushes it. The tail bearing fits on the part of the pinion where the crush sleeve is currently sitting. The crush sleve is free to fall off of the end of the pinion; in fact, it's about 1/16" larger than the shaft of the pinion right there.

Go find out what the scientific method really applies to.... which is the acquisition of new, previously undiscovered knowledge about the unknown, not conjecture about how an item manufactured by the millions is assembled. I rather suspect you're not a scientist by training or trade anyway, so don't lecture me about the scientific method, either.

OBTW I might have an extra solid spacer laying around somewhere too.... do I need to continue allowing you to make yourself look foolish by posting a pic of that, too?

Would you like fries with that, sir?

 

with an auto you might be able to survive wth a 10 bolt for awhile but for those of us that shift our own gears you are looking at disaster waiting to happen.

I have broken 2 axle shafts like uncooked spaghetti and only one of those caused the wheel+axle to come out of the housing. Lucily i was barely crossing the tree when it came completely out. What if it happened on the 1/2 shift (say it cracked on launch and just held on till i hit second) my car would be trashed

for those of us who shift muscle cars as they should be shifted the 10 bolt is a waste of time. I blew out the powertrax (or the ring gear.. im not really sure) in mine two weekends ago and said F this im getting a 9 inch. You wont ever see me worrying about my rear at the line again like I would do with any 10 bolt.

 

I really was trying to have an adult discussion...........

Really didn't care who was wrong or right..........

If the goal of a thread is to win then..............

OK You Win.

I just wanted to indulge in a though provking post.

 

Well, anybody with any experience and common sense with these rears gave you an answer for your thought provoking post. Does'nt really matter who's wrong, right, talking trash, etc...These rears are junk for high performance use period, end of discussion. They are good enough for daily drivers from the factory with low hp output, but anybody that slightly mods for more power and tries to get 100% traction is sooner or later going to be fragging this rear-much deopends on the moon and star alignment for longevity. Sure, you can put 1000hp in front of it and make it live because traction is NOT an issue so it'd be safe to say they can stand up to 1000hp, but when getting down to the nitty gritty when all power is going to hook, it does'nt take much to break these go-cart sized rear diffs, weak parts, bad design what else do you need to know. I'll be the first one to argue GM has a poor diff design, PITA if you need/want to change gears, unsafe with the C-clip BS, and the only way to make these things worth a chit is to have different axle tubes inserted so they have the right kind of axle retension since the c clip elimination kit eats seals and is not practical for daily driven cars, I've had a GM axle tire assembly go past me on the road while my truck sent sparks flying from the diff eating the pavement. So in reality not really much thought provoktion at all, just more magazine bs with guys questioning it to see what other think.

 

Ditto. Blow all 10 bolts outa that thing, you can, with a factory L03. Ask me how, oh just how, I know this one. they just DONT like slicks!

 

For that price 'd get the moser 12-bolt

 

Anyone notice the pic of the brake bracket in that Chevy high performance article. It looks like a drum to disc conversion. Are those brackets custom or does someone sell them?

Here's the pic: