GEAR 7T3950 - Caterpillar

Transmission Clutches and Shafts
Illustration 1 g01328922
Five Transmission Shafts
(1) Transfer gear shaft
(2) Planetary carrier
(3) Output shaft
(4) Intermediate shaft
(5) Gear
(6) Gear
(8) Input shaft
(9) Gear
(11) Gear
(12) Gear
(13) Gear
(14) Gear
(15) Gear
(16) Gear
(17) Gear
(18) Gear
(19) Gear
(20) Gear
(21) Planetary Carrier Note: Gear (5) never meshes with gear (10). The configuration of the four transmission shafts in Illustration 1 is only for illustrative purposes.The transmission contains the following transmission shafts:
Input shaft (1)
Reverse shaft (2)
Intermediate shaft (3)
Output shaft (4)
Transfer gear shaft (21)Input Shaft
Illustration 2 g01336138
Input Shaft
(8) Input shaft
(9) Gear
(10) Gear
(11) Gear
(12) Gear
(13) Gear When clutch pack (C) or clutch pack (D) are engaged, gears (9) and (12) are locked to input shaft (8). Otherwise, the gears are free to rotate.Gears (10), (11), and (13) are permanently splined to the input shaft. These gears always rotate with the input shaft.Reference: See Systems Operation/Testing and Adjusting, "Transmission Clutches" for additional information.Reverse Shaft
Illustration 3 g01336147
Reverse Shaft
(6) Gear
(7) Reverse shaft
(16) Gear When clutch pack (A) is engaged, gear (6) is locked to reverse shaft (7). Otherwise, the gear is free to rotate.Gear (16) is permanently splined to reverse shaft (7).Reference: See Systems Operation/Testing and Adjusting, "Transmission Clutches" for additional information.Intermediate Shaft
Illustration 4 g01336151
Intermediate Shaft
(4) Intermediate shaft
(5) Gear
(14) Gear
(15) Gear
(17) Gear
(18) Gear When clutch pack (E) is engaged, gear (15) is locked to intermediate shaft (4). Otherwise, the gear is free to rotate.When clutch pack (F) is engaged, gear (17) is locked to the intermediate shaft. Otherwise, the gear is free to rotate.Gears (5), (14), and (18) are permanently splined to the intermediate shaft. The gears always rotate with the intermediate shaft.Reference: See Systems Operation/Testing and Adjusting, "Transmission Clutches" for additional information.Output Shaft
Illustration 5 g01336337
Output Shaft
(4) Output shaft
(17) Planetary carrier
(18) Gear
(19) Planetary carrier
(20) Gear Note: The planetary clutches are not shown in Illustration 5. These clutches are located in the front and rear transmission cases.When planetary clutch pack (G) is engaged, planetary carrier (2) will turn output shaft (3). Gear (19) turns the sun gear in the planetary carrier.When planetary clutch pack (B) is engaged, planetary carrier (21) will turn the output shaft. Gear (20) turns the sun gear in the planetary carrier.When clutch pack (H) is engaged, gear (19) is locked to the output shaft. Otherwise, the gear is free to rotate.When clutch pack (J) is engaged, gear (20) is locked to the output shaft. Otherwise, the gear is free to rotate.Reference: See Systems Operation/Testing and Adjusting, "Transmission Clutches" for additional information.Transmission Clutch Engagement
Illustration 6 g01336844
Modulating Valve (Transmission)
Each modulating valve has a designated letter, as shown. The letters have been cast into the transmission housing.Each modulating valve controls an individual clutch. Each letter is assigned to a corresponding modulating valve. See Illustration 6.These letters are used in Table 1 to show the clutches that are engaged for each gear.No more than two clutches are ever engaged at a time. Also, no more than one clutch is ever engaged at one time on any shaft.Note: The tractor speeds in Table 1 are at 2100 engine rpm.
Table 1
Transmission Clutch Engagement
Engine RPM at 2100
Gear Reverse
Shaft Input
Shaft Intermediate
Shaft Output
Shaft
Fourth gear