elemental79

About half a year ago I upgraded my diff with the 4.57 gear set and a new ATS lsd. A couple weeks ago the bearing on the pinion got damaged (about every other rolly thingy looks chewed up). And the diff was making loud noises (the kind of noises associated with improper shimming). I'm going to replace the bearing but not the gear set. But I wish I knew what could have caused the bearing to go bad. I'm not too fond of the idea of re-installing the pinion every 6 months or so. I have not seen anyone else with this problem, but I know there are many people with new gear sets and racing lsds.


Just in case anyone needs to know the car is stock apart from the diff and the car has about 6 hours of road racing on it and a few autocrosses.

Slows2k

To much bearing preload, or reusing the original crush collar can damage the pinion bearing.

The gear needs to be inspected very closly for and signs of damage to the teeth. If there are any nicks/scuffs/gouges in the gear I would not re-use it.

The ATS diff will also need to be taken apart and inspected. Metal from the pinion bearing has been circulating in the diff, you don't want to re-assemble it with metal pieces still inside.

elemental79

The gears are worn but there is no noticible damage. I also replaced the crush coller. I didnt install the pinion myself so its possible it was not installed properly.

Slows2k

You're taking a risk by reusing the gears. They have worn together improperly. If you reassemble everything correctly, the gear can make even more noise than before.

xviper

Which one? Inner or outer?

ksdaoski

have nothing to lose now, except being stranded

gears need to be done by someone who knows what theyre doin

Wisconsin S2k

not necessarily. if his gears go in a worst case scenario, he could damage a lot more than his gears/pinion. most importantly, the LSD comes to mind.

elemental79

its the larger of the bearings that is bad (the one that is pressed onto the end of the pinion. I'm thinking about using my old stock gear set, but that's something id really only want to do if I absolutely had to. I'm going to take a closer look at the pinion. If I cant find any damage then i think ill risk reusing it. I'm not as concerned with noise as much as damaging the LSD. And they say the 4.57 is stronger than stock, so maybe it wont be so bad being a bit worn

Billman250

Dif building is one of the most precise jobs on the car. Lots of experience is needed to get a feel for all the aspects of the job.

It will be a gamble re-using the gearset, as slows2k said.

I'd PM stratocaster a link to this thread, I'm sure he can give you some options. He is doing dif builds, accepting cores, and all that good stuff

Stratocaster

Personally, I would leave the call up to the installer. Here is a true story....

R&P installed, diff picked up and installed by the owner. The installer did not fill it with oil. he owner thought about checking it out, but figured, hey, the installer would have filled it with oil right. So the onwer installs the diff and goes for a ride.The first two mile, not a sound out of the installation. The third and forth however was another story. It started to scream!. The owner pulled over and stopped the car. He now wanted to check the oil level. He got a ride home, leaving the car on the side of the road and grabed some tools, a jack and some oil. He jacks up the car, and opens the fill plug. He could not feel a thing. Next he opens the drain plug. Again, not a drop of oil! So he fills it up and start to drive it again. After a 100 feet the noise is unbearable, so he calls for a tow truck. He tows it home and waits until the morning to inspect the damage.

In the morning, he swaps the OEM diff and the 4.57 diff. He tried to open the case, but could not get the 1/2 shafts out of the diff. So he drops the diff back at the installers. The installer cracked the case and said that the pinion bearing (both) were fried. He replaced the pinion bearing and the diff has now run 3-4k without any issues.

The installer said that the gear set looked just fine. He also did not have to replace the carrier bearing as they looked like new. So let the installer be the judge if you trust him. I did with mine (the above is a personal story )