Posted by Mike (Montreal, Quebec) on Thursday, March 15, 2007 at 21:51:57 :
In Reply to: NP420 vs M37 transmission posted by scott in georgetown on Thursday, March 15, 2007 at 20:33:49 :
Scott,
I believe the difference between an EARLY (1949-1956) and LATE (1956-1968) NP420 is the cluster bearing (or pocket bearing) that holds the countershaft. On the late, it uses CC#1265674 for the rear pocket bearing. Also the input and output shaft pilot diameter and snapring is different.
You can get replacement gears from such places like AB Linn(best prices) or from Memphis Equipment Co. You need to make sure you get the LATE type gears.
Best prices I found on master rebuild kit (bearings and gaskets) is from a company in Oregon called Transmission Exchange Co (www.txchange.com) that sells the NP420 transmission rebuild kit for 49.62$ (pictures above). The bearings are manufactured in Japan by Nachi-Fujikoshi Corp. For reference, Timken sometimes put Nachi bearing in their own packages. The rebuild kit doesn't come with the output yoke oil seal but that is easily available locally. Also, unlike the original front input bearing, the one included in the kit is unshielded so consider this if you go over extreme terrain (it could allow some oil to leak onto the clutch if you are stopping while going down on a very steep incline). And NP200 transfercase rebuild kit goes for 172.25$.
A very good manual to help in the rebuild is the TM9-2520-232-35 technical manual (circa 1959).
If you want to look at the rebuild of my late NP420 (pun intended), please look at the link below.
Regards,
Mike
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