History of the Jeep PTO

webmaster — Wed, 23 Sep 2009 14:02:15 +0000

THE PTO: there are different PTO units for different applications. Make sure you get the correct one for your vehicle. Don’t trust a seller to give you the correct application. More often than not they don’t know and say it fits vehicles it won’t (“fits jeeps”). For example, the models 40, 41, 48, 50, 51, and 58 all mate to a Dana 18 transfer case found on early civilian jeeps. However, the 40 and 41 only fit the truck, wagon, or sedan delivery frame and cannot be used on a CJ. The 50, 51, and 58 were designed to only fit the CJ. Also of importance is where the PTO sends the power (front or rear). The 41 and 51 only send power to the front and have a single shift handle. The models 40, 48, 50, and 58 send power to front but also to the rear. These units have two shift handles. The 40 and 50 power both front and rear together (both on or both off). The 48 and 58 allow selective use of implements (front only, rear only, both, or neither). Twin stick PTOs are rare and cost accordingly.

THE DRIVE SHAFTS AND U-JOINTS: the jeep drive shafts are all 7/8″ diameter steel bar stock with machined in keyway slots. Woodruff keys index the u-joints to the slots in the shafts. The shaft lengths vary by application. To circumvent typical obstacles (crossmembers, exhaust, clutch linkage, etc), a common application will have two shafts, three u-joints, and a center support bearing. For example the early CJ uses a 27 3/8″ front shaft and a 22″ rear shaft. The jeep truck, jeep wagon, or jeep sedan delivery uses a 31.5″ long front shaft and a 17.75″ rear.

Three different jeep universal joints are used in each setup. The front u-joint has one 7/8″ opening with a 3/16″ keyway and one 7/8″ opening with a 1/4″ keyway. The center u-joint has one 7/8″ opening with a 1/4″ keyway and one 7/8″ opening with a 1/4″ keyway. The rear u-joint has one 7/8″ opening with a 1/4″ keyway and one 1″ opening with a 1/4″ keyway. Note all shafts use 1/4″ keyways, but the winch uses a 3/16″ keyway and the PTO, which uses the 1/4″ keyway has a larger 1″ output shaft.

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History of the Jeep PTO