Sherman "Step-Down" (underdrive) ratio:...1.513:1
Direct or standard ratio:..... ..... ..... ..... ..... ..... ..1:1
Sherman "Step-Up" (overdrive) ratio:..... ..... .....1:1.495 PTO RPM vs engine RPM..... ..... ..... ..... ..... ...1000 RPM..... 1500 RPM..... 1750 RPM..... full throttle (2269 RPM)
Step Down(UD)..... ..... .....240..... ..... ....360..... ..... .....420..... ..... ..... .545
Direct Drive (DD)..... ..... .363..... ..... ....545..... ..... .....636..... ..... ..... .823
Step Up (OD)..... ..... ..... ...543..... ..... ....815..... ..... .....951..... ..... .....1231 [Don, this is why I said your pto rpms showed you have a combination Sherman] Gearing order table for an 8N with a Sherman Combination:
[Notice it is non-linear in its pattern.] Gear..... Ratio..... Full Throttle Speed (mph) UD1..... .16.5..... .2.77
UD2..... .13.7..... .3.56
DD1..... .11.0..... .4.19
UD3..... ...9.3..... .4.90
DD2..... ...9.0..... .5.38
OD1..... ...7.2..... .6.26
DD3..... ...6.2..... .7.40
OD2..... ...5.9..... .8.04
UD4..... ...4.4.....10.34
OD3..... ...4.1.....11.06
DD4..... ...2.9.....15.47
OD4..... ...1.9.....23.12 Lubrication:
"A patented oil slinger and return circulate the main transmission lubricant through the "Combination." [This lubrication probably is for all Sherman auxiliary transmissions.] Visual differences between the Sherman Step Up [and presumably Step Down] transmission and the Combination transmission: The combination mounts the shift lever onto the shaft extending through the clutch housing with an allen screw. The lever is flattened for the last several inches where it meets the shaft. The lever extends forward from the shaft at approximately the 10:00 position for approximately 7 inches, and then bends back towards the operator. The Step Up [and presumably Step Down] has the shift lever pressed into the shaft extending through the clutch housing. The lever is non-removable from the shaft. The lever extends from the shaft at approximately the 12:00 position for approximately 2 inches, and then bends back towards the operator Hupp Transmissions and Ratios: D-59..... ..... .OD 1.575, UD 0.528
D-59-2..... ....OD 1.575, UD 0.700
O-49-C..... ..... ..... ..... ...UD 0.700 The Hupp lever extends straight back on the right hand side of the tractor from a shaft coming through the clutch housing. All this information comes from copies of manufacturers documentation I received from The N-Newsletter.
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