So I put all new bearings and seals in my 10 bolt last winter and after 2 months it is making horrendous noise again. I think the pinion bearing went again. ANYWAYS :P It is a 91 drum rear with a 7.625 RG, Posi, 28 spline, etc. I am looking at changing from a 3.23 gear to a 3.73. Since I have to do it over again I want something out of it My dilemma is that im looking around for gears and the price varies from 125$ to 600$. I don't understand the differences between them, is it quality? Id like to only have to spend 125$ but not if the quality is bad or something. Also, anyone have any idea of why my diff made all kinds of whining noise all the sudden,two months after new bearings? and no... i didn't do any burnouts/ donuts. (im pretty sure its a pinion bearing... its the same noise as when the last pinion bearing went) Thank you all a ton in advance. I appreciate all the good advice I get around here

First, you need to figure out why you keep tearing up pinion bearings. Sounds like too much or too little preload. Here's a nickle's worth of free advice: don't use a crush sleeve. Use a solid spacer. They are $10-$15 and worth their weight in gold.

Second, as for the gears do not, I repeat, DO NOT use cheap import ring and pinions, and stay away from Richmonds too (they whine like an angry babby). My advice is get a set of Yukons from Randy's Ring and Pinion. They are around $180 I think. Quiet, easy to set up, a great gearset. They're all I use now. I've installed them in everything from GM Corportate axels to Danas to Ford 8.8s and still no problems after miles and miles of use (much of it hard). The pricey sets are race gears that are softer metal and lighter. They will not live in a street car very long. They are designed to cushion the shock loads of a hard launch on slicks without breaking, but the tradeoff is that they wear out much quicker.

Thanks for the info.

I am going to check the total pre-load of the rear end (the spec is around 40 in lbs) to get a general idea of the pinion pre load so i don't have to disassemble it right now. When I set it up I remember getting it right in spec though... hmm.

I will go with the yukon gears too then.

And Ive read up a little on the solid spacer instead of the crush sleeve but all ive seen are mixed opinions, I guess I can give it a try though. I have nothing to loose at this point...

I'll give you a treat. The solid spacers were designed years ago for 9" Ford rear ends. The following may be a bit of an urban legend, but it's a good story anyway, and the physics involved are true regardless of the characters.

An old associate of mine used to work for a local dirt track car builder and machinist when he was a kid. His name was Sonny Dornberger I believe. He was an old school German machinist, and was very good at solving problems and could build one hell of an engine by the accounts of several people that I've talked to. He found a problem with the Ford 9" rear that caused the gearset failures he was experiencing. He had a meeting with several people from Ford's racing program to discuss it, as they could not figure it out either. When they showed up to his shop he asked whether they would like him to break the rear inside the shop or outside. They looked puzzled, but said "where ever you like". He chose inside the shop to avoid having to push a car with a broken rear. He started the car and proceded to break the gearset in the rear in just a few feet inside the shop. Then he got into an identical car and did the same thing that had broken the first rear, but the second one didn't break. The Ford guys were puzzled, so they asked him to pull the center section out so they could inspect it. Sonny obliged and when they tore down the rear they found a solid piece of chromoly tubing in place of a crush sleeve. That was the only difference. They were amazed, and began marketing a solid spacer kit over the counter with a Ford Racing part number on it, for which Sonny recieved exactly zero dollars.

Folklore aside, the crush sleeve allows the pinion to ocilate back and forth, because certain frequencies can cause the sleeve to expand and contract in response to a third order harmonic. When this happens the gears move out of proper mesh, and under high load conditions either the pinion head will strip teeth, or the ring rear will spit teeth, or the pinion head will snap off (especially with high gearsets as the head is small, like a 4.88). The crush sleeve is also a one time deal, though many people try to reuse them, often with disasterous consequences. A solid spacer will end all this. Dana rears are set up like this from the factory. They use shims to set preload.

What kind of rear do you have? 40 in/lbs is way too much for a 10 bolt. You should have 6-8 with old bearings and 14-19 with new bearings. The only rears I've ever seen with peload close to 40 in./lbs are the big Dana 80s and the Ford 10.25" Sterlings. Too much preload will fry the bearings.

The spec I was talking about was the total preload. this is with the diff and axles in. My alldata is down right now so i dont know the spec exactly but I think its like 35 in lbs. I was trying to avoid having to take out the carrier right now to test the pinion preload. I forget what the preload spec was when I tightened it down but it was alot less than 35... maybe like 20ish?

Go with a good name brand gear and stay away from the HOUSE brand gears, like Summit and Jeg's. Yukon is usually a good gear, but if you use their 9 inch Ford 3.70 you are going to have noise no matter how you set it up. This is a common problem with all brands. Each one has certain gears that have a little noise in them. Richmond gears are not all bad, just some of them. US Gear and Motive Gear are the same way. I can almost guarantee that the house brand gears will make noise.

I know that this goes against popular opinion here, but I've never had a problem with the crush spacers. I have built MANY high performance rear ends, including the rear ends in the first and second quickest cars in Europe (12 bolts with crush spacers in them) and haven't seen any failures becasue of a spacer. The crush spacers are easier to set up if you do it right, but can only be used one time. The only advantage that I see for using the solid spacer is that you can put as much torque on the pinion nut as you want, where you are limited with the crush spacer. Increasing the torque on the nut increases the tension in the pinion shaft, which can help stablize the shaft. I think that the 250 to 300 pounds of torque that you get from the crush spacer is enough. This is just my opinion and experience.

Be that as it may, I've helped friends who built rears for their rigs that shouldn't be breaking gearsets with the power they were running. One is a friend who runs a 4x4 shop and has built more rears than I've seen (over 500 easily), so he knows how to set up a ring and pinion and I will rule improper setup out as a cause of the failure. He was also breaking some serious hardware (Ford 9", GM 10.5" 10-bolt). I finally convinced him to try a solid spacer, and it solved the breakage issues. For the cost involved I cannot see the logic in using a crush sleeve over a solid spacer. Especially for a novice, as you cannot screw up a solid spacer, but you can ruin a crush sleeve. By the time you buy two crush sleeves you could have used a solid spacer.

thanks For the help.

I plan on running yukon 3.73's and a solid spacer.

Once I find those for the best prices etc Ill be getting some higher quality pinion bearings. Then a special tool list since I'm no longer in school so I can't use theirs :P

Yukon is the brand made by Randy's Ring & Pinion, so that's the only place you can get them. Get one of their full overhaul kits and the solid spacer too.

As for tools, you ned an in./lb. torque wrench or drag gauge, a dial indicator & magnetic base, a press is handy but not absolutely necessary, and a pinion depth gauge is also handy but not absoutely necessary.

I had Richmond 3.73s in my 7.625 when I got my '88 into the tens, and they did not whine. They are the strongest gears there are for the 7.625.

I would put the Yukons on par with the Richmonds in terms of strength. I've yet to see a set break. I had Richmonds in my Mustang and they whined something fierce, even though they were set up properly. Based on that experience I will never recommend them. The Yukons for me are a known quantity. They always set up easily and give a good pattern, and I know the quality is there based on the longevity and strength I've seen with them.

I have a set of calipers and a dial indicator from last time, I also have an in lb dial torque wrench.

My question is about the pinion depth, I used the stock depth shim last time (probably a bad choice) so i dont know how to check or setup pinion depth. How is it done and is it hard to do?

Start with the original pinion shim. Install the pinion and set the bearing preload without the crush spacer. Install the differential with the ring gear and set the backlash and bearing preload. Put gear marking compound on 3 teeth that are together and run the pinion gear through it several times in both directions. Read the pattern that is left. Make adjustments to the pinion depth by what the pattern shows you. Put it all back together and do it again. Keep making adjustments until the pattern is where it is suppose to be.

Couldn't have said it better myself. It's a time consuming process, but it saves you buying a $250+ tool to read the depth. If you're only going to do one or two rears investing in the tool is an expense you can spare yourself. If you plan to do a bunch get the tool as it will shorten your install times considerably.

I had my Yukon 3.42's for the 10-bolt set up three times by a professional shop and it still makes a little noise (whine at certain speeds). After talking with the guys at Randy's (great help and customer service), they said that was inherent with those gears and it wasn't going to go away completely.

I love my 3.42s vs. the craptastic stock 2.73s. Just my two cents, I wouldn't go lower than 3.42 on an L98 unless you are planning on driving around town or at the track only. I took my car with the 3.42's on an interstate trip last month and it was like it needed another gear the whole time. Great low end, bad interstate cruising.

I drive on the interstate maybe three times per season, and even then I dont go over 70mph and ive seen the math done and it works out to be under 2500 rpm so thats fine with me.

a 3.42:1 gear with a 26" tire is only 2000 rpm at 65 mph, which is fine unless you chose an annoying muffler.

I usually run about 72-73 and the car is usually pushing about 2200-2400 RPMs. Sure it's fine, but it's not ideal. It still feels like it needs another gear for the interstate. But I know that's just how it is. I still wouldn't trade back for my 2.73s .

I was must making sure the OP knew what he was getting into with the gear change.

i put richmond 4.10s in mine.. no noise at all. you have to use a quality lube, and proper build.

The Richmonds I used whined, period. I replaced every bearing and race with new Timken units, and set all specs to factory. I observed the manufacturer's break in procedure. I used the OEM specified weight gear lube with the correct limited slip addative. I've used two sets of Richmonds with the same results. I've used over a dozen sets of Yukons with no problems. Is it worth taking the chance? The Richmonds are more expensive anyway.

Wont it damage my lower pinion bearing being pressed on and off god knows how many times to get the pinion depth right?

I've only damaged one pinion bearing when pressing it off, and that was on a 9 bolt with Precision Gear 3.70 gears. The press fit was too tight and it would break the bearing each time I pressed it off. I've built several hundred rear ends and pr4ssing the pinion bearing off isn't a big deal. You do need the right bearing seperator and a press to do it.

The Bearing seperator im using looks like this
and then i press down on the non gear side of the pinion. It damaged the old one I took off...

And btw those parts haven't got here yet, hopefully soon

I am fixing to do the exact same thing. My pinion bearing went out and I am swapping to a set of 3.73s.

Can you ellaborate more on the solid spacer? How is setup with it? Thanks

Keep me updated on those parts. If you don't have them tomorrow I need to find out why. That bearing seperator should have worked. What size is it? It might be too small or too large. I think mine is 6 inches.

The parts just arrived at my door step, Thank you. That re-build has a lot more/better parts than the last one. I'm excited to get it done now. I don't know what size it is, we had it lying around at work. Do you just tighten it up until it pops loose or just get it under a bit and use the press force to break the bearing loose? I did the later but I assume you can just use an impact gun on it until it pops loose right?

I tighten it up by hand as much as I can and then put it in the press. Yours might not be getting under the bearing far enough. This is the one that I use.

Yeah, do not use an impact gun on a clamshell; it can bend the bolts. Get it hand tight and then let the press do the heavy lifting. You have to be careful that the bearing cage does not get jambed into the clamshell when you are pressing the bearing off. I usually check that I can still spin the cage as I begin to apply pressure with the press. Check it after every pump on the handle. The bearing gets damaged when the cage gets bent as you are pressing it off. If you look out for this you should be able to save the bearing. That being said if you are setting up a rear without a pinion depth gauge and may have to remove the bearing ten or more times to change shims why take the chance? In that case just make up a setup bearing that is a slip fit. Each time you press the bearing off there's a chance that you will damage it, so why take the chance. It will save you considerable time as well.

3rdgenmaro, the soid spacer replaces the crush sleeve. You set it up just like the crush sleeve, except instead of crushing the sleeve to set the preload you use a solid spacer and shims. More shims decreases the preload, less increases it. It may take several times to get it right, but once you do you can assemble and disassemble the pinion as many times as you want without ever having to replace a crush sleeve, or go through the preload setup. It is a stronger and better way to set preload too (Dana rears are like this from the factory). The crush sleeve can be a weak link, even in an otherwise stout rear like a Ford 9" or GM 12-bolt.

Be very carefull when using one bearing for the trial assemblies and another for the final assembly. I have a customer in Holand right now who took out one bearing and put in another with the same pinion shim and the pinion depth went WAY off. I've seen this happen many times. The tolerance on bearings is pretty tight, but they are not exactly the same. The pinion depth can change just by changing the bearing.

If you use a solid spacer and change the pinion shim you will also have to reset the bearing preload. This is true for the 7.5 and 8.5 rear ends and the 8.2 with after market gears. This is not true for the 12 bolt car and truck rear ends and the 8.2 with GM gears.

I agree that you should always be careful. That being said, I have never had a problem using a setup bearing for checking the pattern and a different bearing for final assembly. I also only use Timken bearings, and the tolerance issue you speak of is why. Timken holds tolerance to something absurd like .000005"; efectively too small to make any difference with the measuring equipment you use to set up a rear. Off brand and import bearings cannot make that claim. When I've done this I always used two of the exact same bearing, one for a setup and the other for final assembly. I also check everything again after final assembly just to be safe. Running the pattern again only takes a minute, and a little marking compound in the gear lube isn't going to hurt anything (you should change the lube after break-in anway).

Yes, if you use a solid spacer and change the pinion shim you will have to reset the preload, but you should not be changing pinion shims anymore when you set the preload for good. Set the preload without a spacer or crush sleeve when you are doing the gear setup. Nothing is going to move around during this action to prevent you from doing it this way. Once the gear setup is right you install everything for the last time and set the preload with the spacer or crush sleeve. Interesting that this only affects certain rear/gearset combinations. That's good to know.

I'm still surprised at how many people want to install the spacer for trial assemblies. That's why I mentioned it. The reason that the 8.5 and 7.5 will change the preload when you change the pinion shim is that the spacer rests on a shelf on the pinion shaft instead of spanning the distance between the bearings. In this case changing the pinion shim will change the distance between the shelf and the outer pinion bearing. In the 12 bolt rear ends the spacer makes contact with both bearings, so changing the pinion shim doesn't change the distance between the bearings.

We have another clamshell like yours at work that i will try this time. I went through the first run tonight and the pinion is too close so I'll run a smaller one in the morning... the only bad thing is that I can only do this once a day since the only press handy is at work :/ also, I noticed spinning the gears very closely that when I spun the gears very slowly there is one spot where it bound up but going at a moderate speed they didn't.. I hope this goes away when I get the piinion depth right. I made sure that the gears and bearings and such were clean before assembly so I dont think anything got caught under the gears either hmm.

You could have a bent carrier. It's not unheard of, especially if the rear broke and locked up solid. You can use the magnetic base and dial indicator to check the runout of the carrier. It's easiest to do this with the ring gear removed. Then you can set the indicator tip of the face where the ring gear mounts (since this face in sure to be true, but the backside of the carrier is usually rough cast or imprecisely machined). You want no more than about .003" runout. If you've got more than that the carrier got tweaked and needs to be replaced.

Update: New clamshell worked great, original pinion shim was .030, I tried .020 and its still to meshed but its getting better. I'm trying .010 tomorrow morning and after that I'm pulling off the gear to check run-out. hopefully .010 will be right on... not with my luck though :P

Also doing a lot of poly bushing swaps, and adding a wonder bar but two of the sway bar holes are stripped and I dont have the right tap so I'll pick that up tomorrow too. then drilling the torque arm rivets to change that bushind an Im set.