New bearings with gear swap?

[Coyote'13]

My car currently has 21k miles on it. I'm going from a 3.73 to 3.31. Do you think I should replace the bearings when I do the swap or the old ones should be good? I just don't want to spend extra money if I dont need to.

Another question is what is the latest and greatest for rear diff fluid for the track pack cars? thanks

 

[me32]

With that many miles it maybe a good idea. But take them out and inspect them.

 

[INEEDA_TERMI]

My car currently has 21k miles on it. I'm going from a 3.73 to 3.31. Do you think I should replace the bearings when I do the swap or the old ones should be good? I just don't want to spend extra money if I dont need to.

Another question is what is the latest and greatest for rear diff fluid for the track pack cars? thanks

I went with motive gear ring & pinion and rebuild kit. Definately upgrade as much as you can while youre in there. The stock bearings are cheesy most companies use the upgraded bearing set from the gt500.

 

[slagburn]

Side bearings should be good at that mileage. I would do the pinion bearings and maybe throw some fresh diff clutches in while you're there.

 

[fishy2k8]

make sure the replacement bearings fit the race in the pinion housing.. it's best to change the race but it can be a pain. I've never changed the race in the housing because ive never run into a pitted one. however, some of those rebuild kits have different pitch bearings and they wont fit the race, throwing off the pinion depth a bunch and would also cause really bad bearing wear. just a heads up. if you can get the pinion bearing off cleanly without hurting it i'd just take the bearing and the shims and press them on the new gear and run it.

 

[burke985]

i just changed my gears out 1000 miles ago i went back to 3.31's and didnt change anything but the gears a and no issues, car has 22,000 miles on it the installer said everything still looked good . Gears are quiet as the day i brought them home originally with the 3.31's and i put Amsoil severe gear lube in also.