Installing a new aluminum driveshaft in a 65 Mustang
This job replaces the factory steel driveshaft in a 1965 Ford Mustang with a lighter aluminum driveshaft. The work involves supporting the car, removing the old shaft from the differential and transmission/slip yoke, transferring or installing U-joints and hardware, fitting the new shaft to the correct length/orientation and torquing the flange bolts before test driving and checking for vibration.
Build Sequence
1. Prepare vehicle and workspace
Park on a flat surface, set the parking brake, chock the front wheels and raise the rear of the car with a floor jack. Support the car on jack stands under the frame or axle. Wear safety gear and ensure adequate lighting.
2. Mark driveshaft orientation
Before unbolting, rotate the driveshaft so flanges and yokes align in a known position. Use a scribe or paint to mark the driveshaft to the differential flange and transmission/yoke so the final installation preserves the original phasing and orientation.
3. Support transmission / transfer case
Place a second jack or support under the transmission tail housing or slip-yoke area if necessary to prevent movement when the driveshaft is removed.
4. Remove driveshaft flange bolts
Loosen and remove the bolts that secure the driveshaft flange to the differential. Keep bolts and any shims organized if reusing. If bolts are rusted, use penetrating oil and a breaker bar or impact if available.
5. Separate driveshaft and remove from vehicle
Slide the driveshaft rearward to disengage the slip yoke from the transmission (or angle to free the flange). Carefully lower the driveshaft; be prepared for some fluid or grease and support the shaft to avoid dropping it.
6. Inspect and prepare components
Inspect the differential yoke, transmission output/spline and U-joints. Replace worn U-joints and clean mounting surfaces. Check new driveshaft length and spline engagement; some aftermarket shafts require trimming or a specific slip-yoke selection.
7. Install new aluminum driveshaft
Align the new driveshaft using the orientation marks, insert the slip yoke into the transmission, and position the flange against the differential. Install new or cleaned bolts finger-tight, then torque in a criss-cross pattern to the manufacturer's spec.
8. Lower vehicle and road-test
Remove jack stands and lower the car. Perform a careful low-speed test drive, listen and feel for vibration. If vibration exists, re-check bolt torque, phasing, and U-joint condition; some imbalance may require professional balancing.
Frequently Asked Questions
Do I need new U-joints when installing an aluminum driveshaft?
You should inspect the U-joints and replace them if there is play, noise, or visible wear. Many installs use new U-joints to ensure reliability; some replacement driveshafts include U-joints—verify with the supplier.
VIEW FULL ARTICLE →Will an aluminum driveshaft cause vibration?
A properly built and balanced aluminum driveshaft should not cause vibration. However, incorrect length, improper phasing/orientation, worn U-joints, or loose bolts can cause vibration. If vibration persists after correct installation, professional dynamic balancing may be required.
VIEW FULL ARTICLE →What torque should I use on the driveshaft flange bolts?
Torque specs vary by bolt size and grade. Use the torque value supplied by the driveshaft manufacturer or typical flange bolt specs for classic Mustangs (consult factory manual). If unsure, use a conservative spec and re-check after a short test drive.
VIEW FULL ARTICLE →Is an aluminum driveshaft safe for a high-power street or race car?
Aluminum driveshafts reduce rotating mass and can be safe for performance use if professionally manufactured with proper wall thickness, spline coordination, and balanced. For very high horsepower or street/competition mix, consult a driveshaft specialist for the correct design.
VIEW FULL ARTICLE →Do I need to shorten or modify the driveshaft for my '65 Mustang?
Possibly. Driveshaft length depends on transmission type (manual or automatic) and any modifications to drivetrain height. Many aftermarket shafts are made to order to the correct length; verify measurements before ordering or be prepared for slip-spline adjustment if applicable.
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Parts Used (3)
Length and spline count must match the Mustang's transmission/differential. Price is a typical aftermarket estimate; actual cost varies by supplier and options (balanced, slip-yoke, flanged ends).
Replace worn U-joints when installing a new driveshaft; many new driveshafts include U-joints but verify. Cost is for a pair of quality replacement U-joints.
Use new grade-correct bolts and lock washers or Loctite as specified by supplier.