Posted by Fred Coldwell on Wednesday, January 23, 2002 at 0:10AM :
In Reply to: 8 3/8ths vs. 9 5/8ths.... posted by Sean on Tuesday, January 22, 2002 at 10:58PM :
Sean:
If you gear set has never been changed out by a previous owner (for which all bets are off), then the quickest way to tell an early 3/4 ton 8-3/4" ring gear diameter pumpkin from a later 9-5/8" ring gear pumpkin is to look at the round tubular top of the pumpkin housing just behind where the propellor (drive) shaft attaches. If there if a square set screw there on top, the pumpkin has the 9-5/8" ring gear (the set screw is for the third bearing holding the pinon). If there is no set screw there, the pumpkin should have a 8-3/4 dia. ring gear (and only 2 bearings holding the pinon). All ring and pinion sets on the 1941-42 WC 1/2 ton trucks have the 4.89 ratio with the 8-3/4" diameter ring gear.
Buy, read and study John Zentmyer's booklet TM9-1808C, "POWER TRAINS AND INTERCHANGES: MILITARY/CIVILIAN TRUCKS 1941 TO 1971 (DODGE)". It answers this question and many more you have not yet thought of. Available from the MVCC, VPW, Portrayal and others for between $12 to $15, plus shipping.