I agree with the above. I'll add that the purpose of the crush sleeve is to provide the proper amount of inner pinion bearing race clamping force upon final assembly so that loads placed upon those races when driving doesn't cause things to move around and loosen up. Crushing the sleeve is somewhat of a delicate operation, it takes alot of torque on the pinion nut to crush the sleeve, and once the bearings contact the races you have to proceed very carefully, checking preload (w/ an in-lb torque wrench) until you achieve the proper preload. If you go too far and get too high of a preload, you've crushed the sleeve too far and you'll have to disassemble and try again with a NEW crush sleeve. If you attempt to just loosen the pinion nut and re-tighten to achieve the proper preload, the crush sleeve, having been already crushed too much, cannot provide adequate race clamping force. It won't be too many miles before your pinion bearings will need replacement again. Crush sleeves are cheap compared to taking it ALL apart again, do it right the first time.

Also, you don't need to install the crush sleeve until after you've shimmed the pinion bearing and set backlash to get the proper gear-mesh pattern.

 

But, the one thing it doesn't seem to address is: What damage can be expected if a pinion seal leak has gone unchecked for so long that the next time oil was added, it took almost the entire two quarts?

I'm a dumbass. This is my situation: I've been hearing noises from the rear end (no, I'm not talking about flatulence! ) recently, so I figured after five years maybe I should change out the Amsoil oil. Well, the adventure didn't start out too well when I stripped the drain plug on my MAC cover with the allen wrench, but I decided that since I got the oil for next to nothing, might as well see if it'll take any. 1 & 3/4 qts. later, it still wasn't completely full (I can't get all of the second quart in because of the hand pump I had to use that screws onto the container). But in any event, I'm still hearing the same noises which I'd describe as sounds separate from what I thought was normal chatter for 3.73 gears. I'm hearing two separate noises. When I'm coasting, I hear a sound similar to *horse hoofs on concrete*, but when I'm on the drive side of the gear I also hear an intermittent, deeper sounding chatter. Tell me if I'm wrong, but I think I've hurt the ring/pinion gears as well as the diff unit.

I'm asking this because I'll be taking my wounded animal up to LG on Saturday so they can do a diagnosis, and I want to be prepared for the worst. I also intend to have the stock 3.23's re-installed.

Also, is it general practice to replace the differential unit in a case like this, or is it just a matter of replacing it's bearings and such? Thanks.

Note to moderators: If I'm posting this in the wrong place, let me know and I'll start a thread with it because I'm very concerned about this situation.

 

No Rich where you are posting is fine. The nice thing about this thread is that it is stickied, so people with the same questions as yourself can find this easily without searching (though they normally start new threads anyway).

Running on a leaking pinion seal will do damage. Not only is it annoying to continuosly wipe gear oil off the floor, but if the rear end doesn't stay full, you're in trouble. Without enough lube to cool & lubricate the moving parts in the rear end, heat starts destroying things quickly.

Unfortunately if the damage is done, it's done, and changing the lube will not help that.

I would venture to say that you have a torsen carrier (as opposed to an auburn) since you mentioned the chattering. The torsens aren't so great - it is a mechanical carrier (worm gears, etc) as opposed to the auburn which is limited slip (i.e. clutch plates) so it does tend to be noisier, especially when it's on the way out.

Are you going back to 3.23s because you don't like the ratio itself, or because of the noise? Because 3.73s are great for automatics, it really wakes them up. I think you might be disapointed going back to 3.23s.

Hopefully LG will be able to tell you if your carrier is going out, or not. Normally we don't replace the diffs because of wear - usually they just flat out break first. I stripped the internal gears on my torsen and that's what did mine in. I noticed a lot of clicking/chattering before it totally went out, so I knew it was only a matter of when, not if.

Whatever gearset you go with, purchase a master install kit to go along with it. That will include all of the bearings, shims, seals, etc that the installer will need.

 

I'm almost certain it's an Auburn limited slip. I say that because I needed to add the GM additive when the new gears were installed. The diff wasn't changed. My reasoning for going back to the 3.23's was two-fold. In the event the installed set is damaged, I can have the stock ring & pinion re-installed to save a little bit of cash, and the other reason is to hopefully see some increase in fuel mileage. If the 3.73's are okay, and the gas cost savings isn't really significant, I guess it would be best to just leave well enough alone, huh? Is the part number of the master install kit dependant on what gearset choice I decide on? I did assume that I'd be buying one, but I wasn't sure if it was absolutely necessary. I do love the pull I get from the 3.73's along with the 3K Vigilante (smoking the tires from a 5-10mph roll is great fun!), but I was kind of getting tired of the chatter. Back in 2000, the prevailing wisdom was that a big gear and chatter went hand-in-hand, but when I talked to Bobby at LG, he indicated to me that if the gears are set up properly, they should be quiet. One thing I do remember, for the short period of time the stock (optioned) 3.23's were in there... no noise.

Sorry for rambling, but now that I think about it, I did do an oil change sometime after the original swap, and the guy that helped me looked at the wear pattern on the gear and said it looked good. I've never seen any drips coming from the cover or on the garage floor, so it's safe to assume the leak wasn't at that seal. A lot of grime has built up on the right side axle housing, the right side of the fuel tank and the right side muffler. What does that tell ya?

I appreciate your insight Keliente.

 

Yeah a leaking pinion seal will throw fluid all over the place and make a big old mess...it's nasty.

Perhaps your auburn is on its way out then...either way the gears themselves will not cause chatter...but if you want the 3.23s for the (slight) gas mileage improvement then you know what is best for your car. The master install kit will be the same for any 10 bolt rear end. A properly set up rear end shouldn't make any noise at all.

 

That's okay, I bought a big-*** can of Gumout! Love that stuff.



Keli, don't ever become a doctor... or nurse!

 

Going to revive this thread that I killed over a month ago...

All in all, a happy ending to my neglect and inaction. It turns out the pinion seal wasn't where the leak occured, that part's still a mystery. The diff was fine, but the pinion bearing was shot. Since the whole assembly had to come apart to install the new bearings, I decided to have the old Motive 3.73's replaced with new Motive 3.73's and now, thanks to a superb setup by Sean at LGM... quiet as a mouse. Sure wish those guys weren't moving to Allen, but I digress.

Here's the bad news: One week after the install and while driving in town, don't you know I got a speeding ticket? My theory is my brain was subconciously judging vehicle speed based on the gear chatter and howl, and when it was silenced my brain went off into the weeds. I sent a message to Bobby @ LG suggesting that his crew was partially responsible and that someone there should take the Defensive Driving class in my place, but for some reason he didn't respond. I think that's only fair, don't you?



Anyway, all is well in the drivetrain again.

P.S. Someone please reply to this because I don't want to see my name next to this thread anymore. I'm not really a thread killer.

 

I find it strange, but of all the real drag cars I've seen and everybody I talked to at the race track that runs a nine inch has usaully taken a 9 inch from an old truck and had it setup for their particular vehicle. None of them said they spent $2500.00 and bought one brand new.

 

People can do whatever they want,why would want to go through the hassel of building one from an old rusty junk yard heap?It takes tools and experence to do things right... you can use the term "Real" drag car however you want.. but I doubt you'll find an OE 3rd member or housing for that matter in a "real" drag car

 

Thats exactly what I am saying, why are people with pure drag cars using junkyard cores to build their setups and us gen III/IV fbody guys are having to buy them brand new? if you know the answer speak up . If not don't post.
No one said anything about the third member being o.e. I'm quite sure the case and the carrier was replaced with something stronger but the the total third member and housing just wasn't purchased brand new. I'm quite sure some chassis shop or something ended up setting up the whole thing, but i doubt it cost $2500.00 to do it.

 

I think it comes down to if you are building a drag car chassis and all you have the tools and experence... 99% of Fbodys are just swaps in the driveway... The things can be bought easly... Its not just taking an old housing and welding brackets on it.... if you want to do it right I think sportsman drag cars are alot like circle track cars you do what you have to to get it done...

 

I can agree with that. The average chassis shop can probably fabricate an entire rear end, but most of these guys have years of experience, and therefore don't mind welding a few extra brackets on a rear end. But like you said, its just a chassis and as long it goes straight nothing else matters.

 

I'm running a 99 SS M6 with open exhaust and an intake. It's not raced, just a DD that's REALLY loud. I just rolled over 90k miles.

Recently I noticed a grinding sound coming from the rearend. It was loud enough that I could hear it over an open-pipe exhaust and custom stereo. My initial thought was brakes or wheel bearings, so I took it to my favorite mechanic to get checked out.

$21 and my car being broken into later...

They told me the noise isn't brakes or wheel bearings, but is probably something with the differential (axle bearings, or worse). They recommended me a shop that I won't be able to go to since it's a cash-only operation, and I essentially live paycheck to paycheck.

--------------------------

Edit: I took the car to the shop my mechanic recommended. Yay check's from credit card companies. :o This guy has been running his little differential/rear end shop for 33 years. It looks run down as all get-out, but he has a rack with his own personal funny car sitting on it. I found this encouraging...

I was getting off of a night shift, so I told him what I'd seen/heard/felt and handed him the keys. When I got the call, he told me that just about every bearing in the rear end was shot, and that the right axle needed to be replaced. His quote? $750

I'm so very glad I took my own mechanic's advice to go to this guy. Given what I've read here about what that work would cost elsewhere, like a stealership, I think I just saved a boatload of money and am getting expert work, to boot.

 

Great write up.

 

anyone have some pros and cons before i do my gear change?

fyi- i got GM 3.73 upgrading from 3.23. many say they will be louder, rev higher, lose topend, make my engine work harder, waste lots more gas, feel like im going faster (ie: im going 70 feels like im going 100) ...etc

i like driving highway..dont mind too much on gas loss. but i dont want any of the others mentioned above?:help:

 

Alright, I read all about 3 and 4 channels. How do I determine which I have? I have 98 TA WS6 w/ M6.

 

I think there should be more information stickied here about the differences between 9" and 10 bolts and 12 bolts. What options can be had with which ones, which gear ratios, and which ones can get which posi trutrc or spool etc. Which ones can get ta's mounted to them.. which ones have brake lines built in vs needing to run new ones or get u bolts or c clips etc etc.. Wish I knew enough to make it

 

yes what tee-boy said how do you tell other than lookin at the car i dont have a lift at home

 

Nice write up..

Something that might could be added for those thinking about a swap..

Will a TCS rear go into a car without TCS without any major difficulties? Will it still be "plug and play?"

 

It is not plug and play. Because the location of the reluctor ring and sensors differ from 3 to 4 channel, you will have some fab to do.

4 channel (TCS) rear end into 3 channel (non TCS) car:

Drill hole into center of pumpkin to mount ABS sensor. Add reluctor ring to differential.

3 channel rear end into 4 channel car:

Just swap axles and backing plates.