SM420 Bearing Question

[Chaparralman1974]

Greetings all!

I did a complete tear down of my SM420 transmission and during the process I found that the splines on the output shaft that go into the coupler that in turn connects to the transfercase are a little worn. They are still serviceable, but the wear is noticeable. I was able to source a NOS output shaft for the transmission and will be swapping over all the gears, synchro's, etc. My question is surrounding the shaft and needle bearings. The inside of the transmission looked immaculate and all the bearings roll free with no sign of wear or play that I can tell. Same with the needle bearings. They are all looking good with zero wear. My question is this, should I just replace them all? Is it required to do so seeing as how I am replacing the shaft? The rebuild kit from Novak which seems to be of pretty good quality is about $240. Overall, that doesn't seem to be a lot of money, but I would prefer to not spend it if I don't have to. If the bearings look good, should I change them out, or do you all think it would be ok if I reuse the bearings that are in there now?


Thanks, Clay

[AussieinNC]

IMHO...use a new kit while its apart and make sure everything is as it should be....

Check inside the bore of the cluster gear and make sure the hardening is not pitted....

I use a light grease to hold the small roller bearings inside the cluster and input shaft.

[Chaparralman1974]

Yeah, I am thinking that is probably the best way to go about it. Thanks for the sanity check! :-)