1942 - 1947 Chevrolet Shop Manual



	4-26



	Fig. 52—3/4-Ton Long W.B., 1-1/2-Ton and C.O.E. Front Propeller Shaft and Support

	SPEEDOMETER ADAPTER A speedometer adapter is used to secure proper speed and odometer readings with the rear axle in either high or low speeds. The shift rod which shifts the gear ratios in the adapter is connected to the axle shift lever so that whenever a change in ratio is made at the rear axle a corresponding change is made in the speedometer adapter. PROPELLER SHAFTS Because the passenger car and 1/2-ton commercial cars use the torque-tube drive principle, while all 3/4-ton, 1-1/2-ton heavy duty and C.O.E, trucks have the Hotchkiss, drive, service operations on the various units vary according to the type drive used. Service operations on the passenger car and 1/2-ton commercial car propeller shafts are covered in the first part of this section. 4-TON LONG WHEELBASE PANEL, 1-1/2-TON HEAVY DUTY AND C.O.E. TRUCKS The drive line from the transmission to the rear axle comprises two tubular propeller shafts and three needle bearing universal joints. On the front propeller shaft the rear yoke of the front universal joint is an integral part of the propeller shaft. The rear end of this shaft is machined to receive the support bearing, and it is also splined and threaded to mount the front yoke of the intermediate universal joint, Fig. 52. The support bearing is mounted in the support bracket by means of a rubber cushion which fits over the outer race of the bearing and inside a	sleeve in the support bracket. This bearing is of the permanently lubricated and sealed type. On the rear propeller shaft the front yoke of the rear universal joint is an integral part of the propeller shaft. The front end of this shaft is splined to fit the splines in the rear yoke of the intermediate universal joint. UNIVERSAL JOINTS All three universal joints are of the needle bearing type. The front and rear yoke of each universal joint is machined to receive the trunnion bearings. The bearings are anchored to the front yokes of the front and intermediate universals and the rear yoke of the rear universal by "U" clamps. The bearings in the rear yokes of the front and intermediate universals and the front yoke of the rear universal are pressed into the yokes and locked by snap rings. The front yoke of the front universal is splined to the transmission main shaft, and the rear yoke of the rear universal is splined to the rear axle drive pinion. Each trunnion is drilled and fed by a central lubrication fitting for lubricating the bearings, Fig. 53. On the side opposite the lubrication fitting, a relief valve is mounted. This valve is adjusted to "pop" at from 40 to 80 pounds' pressure, thereby preventing over-lubrication or damage to the trunnion bearing seals. A lubrication fitting is mounted on the rear yoke of the intermediate universal to lubricate the splines, Fig. 53. A plug is staked into the forward end of the splined opening to retain the lubricant. A small hole is drilled in the center of this plug to relieve trapped air. The rear end of the splined