Hiya Freddie,

A few years back you helped me with the install of a ring and pinion. Everything went great - I've been driving the car for 4 years now and it's been dead quiet. They probably have about 2-4K miles on them.

However, I noticed this past weekend that around 50 mph and under load, the rear is making a little gear whine. No noise during coasting and gets quieter as I approach 60 mph. The gears I put in were a used GM 15-41 set. I put fresh oil in when I did the swap, but never changed it since then because the mileage has been low. Could this be an issue?

Any thoughts why this is happening or what could be causing this?

Thanks for your help!
Mike

Have you checked the pinion nut to see if it has come loose? Many times this is the problem. If not then you might want to take the cover off and look for signs of wear.

Ok, thanks. Will do!!

Freddie,

Quick check...

I used a shim setup with this install, and just to be sure, I think you recommended 150 ft-lb torque with red loctite on the pinion nut- right?

Thanks again!
Mike

If you used a solid spacer then you could have gone to 200 foot pounds, which is what I usually do. If you went to 150 then that should be all right too. If you went to 150 then don't change it. Even with the solid spacer you can change the preload by changing the amount of torque on the nut. Use the Locktite.

Hi Freddie,

So I finally checked the pinion nut. I put an impact wrench on it and it basically didn't budge - perhaps 1/16 of a rotation. So it's definately tight.

This was a used gear set and one thing I didn't do and wish I had - change the oil after about 200-500 miles.

I was thinking of dumping the oil and putting some royal purple in to see if it helps.

Your thoughts? Thanks again!
Mike

I'm certainly not gonna try and match Freddie on experience - but if I might suggest ...

If you're gonna pull the cover to change fluids it wouldn't be a bad idea to throw a dial indicator on it and recheck the Backlash to be certain it is with-in the original installation specs.
I've done a couple used gear sets installs and found the backlash seemed to open up a tad after several thousand miles.

You might have a bearing going bad. Checking the backlash is a good idea. I would remove the axles and differential and check the pinion bearing preload again and see if it turns smooth and easy. Check the differential bearings while it's out.

I agree. While it's apart I'll check the backlash. I know when I had the driveshaft out today, I did notice there "seemed" to be a lot of backlash... I have a hunch thats the problem.

So if the pinion checks out OK, I guess I could just re-set the backlash back to about .006, check the pattern and put it back together.

And if the pinion stays in, I'll measure it's rotating torque and be sure it's smooth - I think it should be no less than about 8 in-lb - right?

Next, I could only check the carrier bearing preload by measuring the rotating torque of the entire assembly. So how much additional rotating torque should the carrier have above the pinion?

BTW - these were all new bearings and races I installed, but now they're slightly broken in.

Thanks again guys
Mike

It's almost impossible to measure the differential bearing preload. Just put the shims in tight enough that you can't pull the differential out by hand, but not so tight that you damage the shims or housing when you drive them in.

ok - thanks again!

Freddie,

So I checked and it looks like the backlash opened up to .011 and the bearings seem OK. I think that should be ok - right?

When I installed the gears, I set them to about .007 when I centered the pattern. (Keep in mind these were used GM 2-series 15-41 gears to begin with)

I also noticed a couple of the shims shifted slightly outward and touched the rear cover...

But your thoughts - Worth taking everything apart to re-setup?

Thanks,
Mike

I'm wondering if you got the shims tight enough. Did you check the bearings when you pressed them on to be sure that they were seated completely? Try shimming it again and get the shims as tight as you can get them without damaging the housing or shims.

Freddie,

So I checked and it looks like the backlash opened up to .011 and the bearings seem OK. I think that should be ok - right?

When I installed the gears, I set them to about .007 when I centered the pattern. (Keep in mind these were used GM 2-series 15-41 gears to begin with)

I also noticed a couple of the shims shifted slightly outward and touched the rear cover...

But your thoughts - Worth taking everything apart to re-setup?

Thanks,
Mike

All things I might have expected to find Mike, so it looks like you may have found your problem.
Lots of things will make an axle 'sing' - but under load, bearings and excessive backlash seem to top the list for me many times ...

I agree with Freddie, they may not have gotten the bearings fully seated before you assembled.
Or ... shimming may have been on the 'loose-side' and opened up a tad after run-in.

I would reset baclash (if Freddie approves also) and recheck.
Be sure to try to capture the 'thinner' shim pieces under the bearing cap if possible to prevent them from moving out under load.
In other words, set up the shims like:
l-l-l-l or however they stack-up ... with the thin ones trapped under the cap(s).

Hope this helps and Freddie chimes-in with more!

Thanks for the help guys,

Some news....

I took the bearing caps off the diff carrier and the shims were actually loose. WTF? No wonder it was making some noise.

Thing is, when I set the gears up, I lightly tapped the shims in and it was tricky. I definately had some preload when I put it back together. Perhaps I didn't have the bearings fully seated on the carrier, but I'm almost 100% sure they were.

I also noticed a small amount of teeny weeny chips and metal dust in the oil. GEEZ! I just hope the gears are still ok since they are kinda hard to find... I guess I should probably replace the carrier bearings even though they look OK

I'll let you know how the pinion is after I check it's running torque.

Thanks again

I always use a .001 feeler gauge to check the bearings and see if they are seated completely. If they are not completely seated it will cause problems later.

Hi again Freddie,

Was wondering, did you have any opinion regarding Federal Mogul vs. Timkin bearings? I would think they both are OK. Your thoughts?

Thanks again

Mike

Most of the Federal bearings that I have seen were made in China. If they are made in China you DON'T want them. I'd rather use BCA or Koyo if Timken isn't available.

Hi again BGH,

I tried using a standard two jaw gear/bearing puller for the differential housing side roller bearings, but didn't have much luck, the lip to pull on is very small.

Did you have a tool recommendation for this? Thanks again!

Mike

I think you need a hyrdaulic shop press and a bearing separator plate. HF sells a decent enough shop press for under $100. After you're done using it it makes a great place to hang your coveralls and shop towels.

Any decent shop should do the job for just a few bucks.

http://www.harborfreight.com/6-ton-shop-press-4711.html

http://www.harborfreight.com/large-bearing-separator-3979.html

all beautifully produced by the C&H Ina Co.

Hi again BGH,

I tried using a standard two jaw gear/bearing puller for the differential housing side roller bearings, but didn't have much luck, the lip to pull on is very small.

Did you have a tool recommendation for this? Thanks again!

Mike

Mike:
If it's okay I'll chime-in here ...
You can get the carrier bearings off many ways :yes:
Many suppliers even sell lower cost dedicated carrier bearing pullers for given design units.
BUT - you will need a decent press to get them re-installed anyway, so it's best to press them off and then back on to prevent any damage to the carrier itself.

IIWY - I would find a local machine shop to do the removal and reinstallation for you.
It will probably cost less than $50 to have all them removed and replaced.
If you source the Bearings (still Timkin or BCA) from the shop it might even be less ;)
A small price to make sure no damage is done to the unit ...

If you have the need for a decent press from time to time anyway, now would be a good time to head to Harbor Freight and pick up one of their shop presses.
Even the 20-ton unit is under $200 and a bargain if you do much press work over a project(s) lifetime :thumbsup:
The 'smaller' 12-ton unit would also work for 90% of the stuff you'll probably need it for.
AND! - as an added bonus, you can stop by a store on the way there and pick-up most any copy of a car 'Gearhead Hobby' magazine and there will be a 20% OFF coupon in the Harbor Freight add! (Just checked my copy of "Classic Trucks" and there is a coupon in there also :D ).

Hopefully Freddie will chime in again soon with his thoughts :cool:

ps: and Al still can type faster than me :o

http://thumb7.webshots.net/s/thumb3/1/20/59/55412059QFWDWf_th.jpg (http://rides.webshots.com/photo/1055412059041712107QFWDWf)
This is the bearing puller that I use. I've pulled hundreds of bearings with it and it works very well. It's a little expensive, but well worth the money for someone who does this a lot. I paid around $350 for this one, but the price has gone down a bunch lately. I think they are around $235 now. That's probably more than anyone would want to spend on a tool to use it one time, so you might want to go to a machine shop or find someone with the tools to do this. A regular bearing puller just doesn't work, as you have already found out.

Hi guys,

Thanks for the replies. Ironically, I have the Harbor Freight hydraulic press already - I bought it several years ago when I started the rebuild on my car and it has been of great utility on control arm bushings, trans rebuild etc.

I also have the bearing splitter you show, but the blade portion of the splitter is too thick to get under the bearing. I'm a little concerned about starting to tighten that thing around the base of the bearing.

I was kinda thinking this tool might be worth considering since the jaws on my standard 2-jaw puller keep "popping" off when I try to tighten the center bolt:

http://www.usatoolwarehouse.com/usatoolwarehouse/OTC-4520.html

Has anyone ever used this tool? Any good? If not, I'll speak to shop or ship my unit to you Freddie :-)

Thanks again y'all
Mike

Hi guys,

Thanks for the replies. Ironically, I have the Harbor Freight hydraulic press already ...

...
Has anyone ever used this tool? Any good? ...

Mike

:yes: I have several Snap-On sets like that for helping to hold the jaws in contact with the bearing like this one - http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=10213&group_ID=1219&store=snapon-store&dir=catalog
They work okay for some jobs, but are often not the best set-up for trying to pull a bearing, specially if I think I may need to re-use it.

A press, with the correct bearing collars and set-up, is still my prefered method of removing and installing any precision bearing ...

I haven't seen one of those bearing pullers before. Looks like it could work.

Hi Freddie,

So I was able to pull the bearings, and this time installed the new ones correctly - fully bottomed!

Since I have GM gears, I looked in my GM shop manual for the 12 bolt rear and it specifies that the backlash should be between .003 and .010 with .005 to .008 preferred.

I was quickly able to re-install the carrier with a .005 backlash - I was going to go with it since it will likely "wear-in" slightly and open up a little...

Do you feel this is too tight of a setup for a used set of gears? Appreciate your thoughts.

Thanks again,
Mike

Yes, I think that is too tight for used gears. I would try to get somewhere between .009 and .012 and about .010 would be my target.

BGH,

When we originally spoke (several years ago) and set these gears up, I used a goal of 006-.007 per your advice and I set them at .007 and they were great. Any particular reason for an increase?

Thanks,
Mike

If you had them at .007 then set them back to .007 or .008. A used set of gears usually has about .002 worn off, so setting them tight isn't the way to go. They need to be set back to what they were when they were removed. If you had them at .007 several years ago then they might have a little more wear on them, and they might not, but you shouldn't set them tighter.

OK!! will do.

Thanks again!