Driveshaft - Rear

This procedure covers removal and installation of the rear driveshaft on a 1972 Ford F-100 with 302ci V8, including U-joint service at the differential and transmission yoke connections.

Warnings

Tools required

Parts

• Rear driveshaft × 1 — Use OEM specification
• Universal joint (front) × 1 — Spicer 5-260X or equivalent
• Universal joint (rear) × 1 — Spicer 5-260X or equivalent
• U-joint strap bolts × 4 — OEM or Grade 8 replacement
• Differential pinion yoke nut × 1 — Use new self-locking nut

Fluids

• 80W-90 GL-5 gear oil — 0.5 qt

Preparation

1. Park vehicle on level ground and engage parking brake.
2. Chock front wheels securely.
3. Raise rear of vehicle with floor jack at rear axle center section.
4. Position jack stands under frame rails behind rear spring mounts and lower vehicle onto stands. Rear axle should hang free.
5. Verify vehicle is stable and secure before proceeding.
6. Position drain pan under rear differential to catch any fluid spillage.

Procedure

1. 1

   Mark driveshaft phasing
   Use center punch or paint marker to mark the relationship between the driveshaft and the rear differential pinion yoke. Make matching marks on the driveshaft tube and the differential yoke flange so the driveshaft can be reinstalled in the exact same orientation. Also mark the relationship between the driveshaft slip yoke and the transmission output shaft if the slip yoke will be removed. Proper phasing prevents vibration.
2. 2

   Remove rear U-joint strap bolts
   Locate the two U-joint straps securing the rear U-joint to the differential pinion yoke. Remove the 4 U-joint strap bolts. The rear yoke on this vehicle typically uses an external-strap style U-joint; verify the exact U-joint series against the OEM/Spicer application catalog before ordering. Use a socket wrench to remove all four bolts. Keep the straps and hardware together if reusing.
   Torque spec

   U-Joint Strap Bolts35 Nm (26 lb-ft)
3. 3

   Separate rear U-joint from differential
   Use a pry bar to gently separate the rear U-joint from the pinion yoke. The bearing caps should slide out of the yoke ears once the straps are removed. If tight, tap the yoke ears gently with a rubber mallet while prying. Do not damage the pinion yoke or seal. Allow the rear of the driveshaft to drop slightly once free.
4. 4

   Support and remove driveshaft at transmission
   Support the weight of the driveshaft with one hand or a transmission jack. Slide the driveshaft rearward approximately 2-3 inches to disengage the slip yoke from the transmission output shaft. Once clear of the transmission, lower the rear of the driveshaft and carefully pull the entire assembly rearward and downward to remove it from under the vehicle. Be prepared for residual transmission fluid to drain from the tailshaft housing.
5. 5

   Inspect driveshaft and U-joints
   With the driveshaft removed, thoroughly inspect both U-joints for wear, looseness, or rust. Check the slip yoke splines for wear or galling. Inspect the driveshaft tube for dents, damage, or balance weight loss. Check the differential pinion yoke and transmission output shaft splines for damage. Rotate each U-joint bearing cap by hand to feel for roughness, binding, or excessive play. If any U-joint shows wear, both should be replaced as a pair for balanced operation.
6. 6

   Replace U-joints if necessary
   If U-joint replacement is required, secure the driveshaft in a vise (clamping on the yoke, not the tube). Use a U-joint press or C-clamp with sockets to press out the old bearing caps. Remove the snaprings first if present. Press in new U-joint bearing caps, ensuring they are fully seated and snaprings are installed. New U-joints should rotate smoothly with slight resistance. Do not allow the bearing caps to rotate during installation as needle bearings can fall out of place.
7. 7

   Clean mating surfaces
   Use a wire brush to clean the differential pinion yoke ears, the driveshaft U-joint surfaces, and the transmission output shaft splines. Remove all dirt, rust, and old lubricant. Clean the U-joint strap bolt holes in the pinion yoke with a wire brush or thread chaser. Wipe all surfaces clean with a shop rag. Apply a light coat of lithium-based chassis grease to the slip yoke splines and the transmission output shaft splines.
8. 8

   Install driveshaft at transmission
   Align the slip yoke with the transmission output shaft, observing any alignment marks made during disassembly. Carefully slide the slip yoke into the transmission tailshaft housing, ensuring the splines engage properly. Push the driveshaft forward until the slip yoke is fully seated with approximately 1 inch of spline engagement visible (the slip yoke should not bottom out). Support the rear of the driveshaft while positioning.
9. 9

   Install rear U-joint to differential
   Align the phasing marks made during disassembly. Lift the rear of the driveshaft and position the rear U-joint bearing caps into the differential pinion yoke ears. Ensure the bearing caps seat fully into the yoke recesses. If the fit is tight, tap the yoke ears gently with a rubber mallet to help the bearing caps seat. Verify the U-joint cross is centered in the yoke before installing straps.
10. 10

    Install U-joint straps and bolts
    Position the U-joint straps over the bearing caps. Apply medium-strength thread locker to the threads of all 4 U-joint strap bolts. Start all four bolts by hand to ensure proper thread engagement. Tighten the bolts in a crisscross pattern to ensure even pressure on the bearing caps. Torque all four bolts to specification.
    Torque spec

    U-Joint Strap Bolts35 Nm (26 lb-ft)
11. 11

    Check driveshaft operation
    Rotate the driveshaft by hand through several complete revolutions. It should rotate smoothly without binding, clicking, or excessive resistance. Check that the slip yoke slides smoothly in the transmission output shaft without binding. Verify that all U-joint movements are smooth and that the straps are secure. Check for any contact between the driveshaft and exhaust, frame, or crossmembers through the full range of suspension travel.
12. 12

    Check and top off differential fluid
    Locate the differential fill plug on the rear axle housing (typically on the driver side). Remove the fill plug and check the fluid level. The fluid should be level with the bottom of the fill hole. If low, add 80W-90 GL-5 gear oil (add limited-slip friction modifier if the axle is a Traction-Lok limited-slip unit) until it reaches the proper level. Reinstall the fill plug and tighten securely. Wipe away any spilled fluid.

Reassembly

1. Ensure all torque specifications have been met, particularly U-joint strap bolts.
2. Verify driveshaft phasing marks are properly aligned.
3. Confirm slip yoke has proper engagement depth in transmission output shaft.
4. Check that no tools or parts have been left under the vehicle.

Verification

• Start the engine and allow it to idle. Listen for any unusual noises from the driveline.
• With the vehicle still on jack stands and in neutral, check for any driveshaft runout or visible wobble while spinning slowly.
• Carefully remove jack stands and lower vehicle to the ground.
• Test drive the vehicle at various speeds (20, 40, 60 mph if safe to do so) and check for vibration, unusual noises, or driveline clunking during acceleration and deceleration.
• If any vibration is present, verify phasing marks were correctly aligned and all U-joint fasteners are properly torqued.
• After the first 50-100 miles, recheck U-joint strap bolt torque to ensure they have not loosened.

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