SM420 '48-'67 MANUAL

SM420 TRANSMISSION PARTS & REBUILD KITS

GM TRUCKS '48-'67:

'47-'53: 6-digit casting number such as "59XXXX", all synchro rings are different.

'54-'63: Bearing retainer snout has no weep hole at 6 o'clock, input seal is neoprene.

'64-'67: 7-digit casting number such as "37XXXXX", "38XXXXX", or "39XXXXX", and identical 3-4 synchro rings.