Why do my 9" carrier bearings look like this?

Gatorac · #1 (**permalink**) 10-20-2009, 04:15 PM

On my 2nd day at Barber my diff started to make some unhappy noises. It was howling. The howling changed only with speed and not on or off the throttle. Is this the failure or a result from some other failure? I'm planning on just replacing the bearings as I can't see any other issues. The oil was metallic looking.

trularin · #2 (**permalink**) 10-20-2009, 04:24 PM

Looks like you have/had metal filings in the fluids that mashed between the bearing race and bearing rollers. Then, it looks like the fluid ran low and got hot and baked into a sludgy mess.

A rebuild, clutches and all, is in order. What does the ring and pinion look like?

trularin · #3 (**permalink**) 10-20-2009, 04:25 PM

Oh, and BTW, this would have called banshees.

wrench87 · #4 (**permalink**) 10-20-2009, 04:38 PM

it looks like you had too much preload on the carrier bearings, you have to leave a liitle room for the differential lube to do its job. i worked for a jeep dealership for 15 years and i use to see the carriers set to tight from the factory and ruin the carrier bearings, we use to take 3to4 thousands off each side by installing different shims. on a 9 inch ford you just have to set a little less preload with the screw in adjusters.

Gatorac · #5 (**permalink**) 10-20-2009, 04:53 PM

This is a Tru-Track diff so there are no clutches. Ring and pinion look fine. Pinion bearing feels fine too.

Please disregard the stuff on the bench top. It's not fluid from the diff. Leftovers from other projects....

Barnsnake · #6 (**permalink**) 10-20-2009, 07:58 PM

With the amount of metal liberated by that bearing failure, you will want to disassemble and wash EVERYTHING, including the housing. The surface metal that has spalled off of the rollers and race is very hard. After that metal has circulated to any degree, I wouldn't re-use any bearings in that rear. Take a long close look at those gears after they've been cleaned and dried. It's better to spend a little more now rather than have it even worse in 500 miles.

Rick Parker · #7 (**permalink**) 10-20-2009, 08:01 PM

Gatorac:

When you Road Race with a live rear axle you must take preventative measures to keep the lubricant in the pumpkin. What happens is the oil gets forced into the axle tubes in sweeping turns and the bearings (and gears) run dry. The cure are special seals that are fit into the axle tubes to prevent the oil from being forced into the tubes by centrifical force. Circle Track racers know about this all to well.

venum14 · #8 (**permalink**) 10-20-2009, 09:05 PM

Gatorac:

Rick makes a good point about keeping the oil in the center section not the axle tubes (solid axle only). Seals-It and Speedway Motors carry the seals for the inside of the axle tubes. There are many other factors that could cause your race and bearing pitting/delaminating. Is there another wear spot in the race 180 degrees from the one pictured? If so, it could be an out-of- round bore for the race caused by a burr, chip, etc. When the caps are torqued, the race becomes egg shaped and then the rollers have extra preload across the smaller diameter. Look at the country of origin on the bearings, it is getting difficult to find "Made in USA" but the top differential guys sell them. In addition, not all gear oils are created equal, great reading at http://www.synthetic-oil-tech.com/Ge...te%20Paper.pdf.

RICK LAKE · #9 (**permalink**) 10-21-2009, 03:09 AM

Gatorac Jim, are there any names on the bearing race or rooler race? If not they are made in China. GM used the same cheap bearing in their trucks and they look just like yours in the 1/2 and 3/4 ton light duty trucks. You need to get Green or Timpken bearings for starters. China doesn't know how to harden surfaces yet without failures like this.

If you are going to road race the car you need to look at installing a rear end cooler and pump. I am not a big fan of the inner seals in the rearend because the axle bearings need lube too.
Your gear set may be OK but I wouldnot use them again. The hardness takes a beating when the carrier starts to wobble around in the pumpkin.
Hi temp rearend oil should also be added. Your trans may be facing the same issues of being overheated when racing. You might want to look at Morris photos for ideas if you keep racing, rearend and trans. Niether system is hard to install, just use relays on the pumps. Rick L. Ps doing this to my car too.

Gatorac · #10 (**permalink**) 10-21-2009, 05:30 AM

Quote:

Originally Posted by Rick Parker

Gatorac:

When you Road Race with a live rear axle you must take preventative measures to keep the lubricant in the pumpkin. What happens is the oil gets forced into the axle tubes in sweeping turns and the bearings (and gears) run dry. The cure are special seals that are fit into the axle tubes to prevent the oil from being forced into the tubes by centrifical force. Circle Track racers know about this all to well.

This axle is set up like a circle track car. The seals are in the pumpkin and no oil is in the axle tubes. The wheel bearings are grease packed.

Gatorac · #11 (**permalink**) 10-21-2009, 05:40 AM

A little more history. I have 60 hours on this car all on track. The car currently has 302 hours on it. I have maintenance and repair logs that may or may not be complete. I haven't looked specifically for rear end work, but I don't remember seeing anything done to the rear other then fluid changes. The diff is a Truetrac. This is out of my Panoz.

Gatorac · #12 (**permalink**) 10-22-2009, 08:24 AM

I'm going to replace everything except the diff itself. Changing the gear ratio too. Upon disassembly of the pinion gear, I found no crush sleeve between the bearings. Just when I thought I had this all figured out....

elmariachi · #13 (**permalink**) 10-22-2009, 08:31 AM

Jim, if you'd be so inclined, call Lynn at the 9" Factory, 1-800-332-3450 and tell her Jim in Texas with the Hurricane told you to call. These folks warrant their work and are experts on 9" stuff. I have one of their axles with the newer-style sealed bearings and it is first class stuff.

Good luck,

Jim

Gatorac · #14 (**permalink**) 10-22-2009, 08:44 AM

I already have the parts and not enought time to send it of and wait. Thanks for the refferal though.

elmariachi · #15 (**permalink**) 10-22-2009, 09:56 AM

Quote:

Originally Posted by Gatorac

I already have the parts and not enought time to send it of and wait. Thanks for the refferal though.

I was not suggesting that you send it off, I was suggesting them as a source for parts and or axles.

Good luck.

blykins · #16 (**permalink**) 10-22-2009, 12:14 PM

Quote:

Originally Posted by Gatorac

I'm going to replace everything except the diff itself. Changing the gear ratio too. Upon disassembly of the pinion gear, I found no crush sleeve between the bearings. Just when I thought I had this all figured out....

Did it have a solid spacer instead? I hate crush sleeves.

undy · #17 (**permalink**) 10-22-2009, 03:18 PM

Too much preload, too little preload, incorrect loading, run low on lubricant ...or run too hot on the track (diff needs pump, cooler, plumbing and 12 volts).

Gatorac · #18 (**permalink**) 10-22-2009, 04:36 PM

It must be a solid spacer. I could have swore after I pulled the seal out that the spacer was on top of the bearing. But that's not possible. Any difference in setting preload with the solid spacer? My Snap On buddy is sending me his torque wrench to measure the preload.

More fun stuff today.... Got home with the parts and found that I have a modified pinion support. The inner bearing is larger then the outer, standard size. Had to call every place in town today to find the right bearing and race. Doesn't anybody carry fricken Timken anymore? Geesh..

Tex Racing, which built the diffs for Panoz, has a pump that fits inside the diff. That's what the GTS cars have. Less plumbing and it's driven off of the pinion. The cooler is not in the budget (time or money) right now. I have not heard of another GTRA or GTWC with diff problems due to heat so I'm going to leave the cooler out for now. I would think that failing diff seals would be the first indication of a heat problem. My seals are doing fine. No oil in the tubes or wheel bearings. If need be I will add the external electric one later. The importer of those electric pumps is right around the corner from my shop.

Rick Parker · #19 (**permalink**) 10-22-2009, 07:30 PM

The carrier with the different sized bearings is aptly named a Daytona Pinion Carrier which is designed to carry more torque than the one which uses the same sized bearings on each end, it originated in Cup Racing many years ago. It provides better support for the end of the pinion with the gear. Be glad you have it. You better have a BIG torque wrench and a Bigger vise. You'll have to resize the spacer. If you're racing be sure to use the solid spacer. Setup will take more time. Start with .488 or longer so the bearings are not damaged when you torque the nut to set the preload. If you're racing, good idea to get the Viton seal (Ford Racing, maybe other suppliers too) as it will take more heat than a standrd replacement one. Use anti seize on the threads and set the torque wrench to 240-260 lbs. Without anti seize 160 lbs, but it is harder on the threads. Do not reuse the pinion nut you took off. Try Autozone if they are in your area, Timken is what they stock.

Gatorac · #20 (**permalink**) 10-23-2009, 05:16 PM

Quote:

You'll have to resize the spacer. If you're racing be sure to use the solid spacer. Setup will take more time. Start with .488 or longer so the bearings are not damaged when you torque the nut to set the preload. If you're racing, good idea to get the Viton seal (Ford Racing, maybe other suppliers too) as it will take more heat than a standrd replacement one. Use anti seize on the threads and set the torque wrench to 240-260 lbs. Without anti seize 160 lbs, but it is harder on the threads.

Thanks for the info. For my first complete rebuild of a rearend, I need more info.

I understand how preload works with the crush sleeve but I'm a bit in the dark with the solid spacer. How do you come up with the thickness of the spacer? You don't compress the solid spacer like a crush sleeve, do you? It would seem like you would need to now the exact thickness needed or shim the spacer. Is it trial and error with different thicknesses? Can anyone fill in the blanks or should I just go with the crush sleeve that came in the bearing kit? Backlash and pinion depth happens on Saturday. Pinion preload can be finished up later if need be.

Thanks for all the input. That's why I post here. Some smart folks over here.