DIY Network

1962 Fort T-Bird: Limited-Slip Differential From "Classic Car Restoration" episode DCR-304

A limited-slip differential supplies power to both rear tires.

In this segment, the rear axle of the T-bird gets upgraded from an open differential to a limited-slip differential. Auto-restoration expert Keller Wallace joins host Steve Magnante to help out with this phase of the project. Following is a summary of the major steps in the installation of new differential as shown in the episode.

Materials:

Standard automotive tools (socket wrenches, extensions, combination wrenches, screwdrivers, nut-drivers, etc.)
Air compressor and impact wrenches
Limited-slip differential kit
Jack and jack-stands
Floor-jack
Catch-basin
Razor knife
Replacement gear-lube
Brake cleaner
Rags

Safety Equipment:

Work gloves
Safety glasses or other eye protection

Safety Alert: Always wear eye protection when working with power tools or pneumatic tools.

Note: This is a summary of steps included in the automotive restoration procedures shown in this episode of Classic Car Restoration. These are general guidelines for restoration procedures on this particular make and model of vehicle, and for the level of restoration selected for this project. There may be variations in procedures depending on model, condition of vehicle, level of restoration undertaken and the types of replacement parts or upgrade kits selected. Always follow proper safety precautions, and read and follow manufacturer's guidelines, diagrams and safety notices that come with any replacement parts or kit that you select.

	Ford's 9-inch rear axle gets its name because of the diameter of its ring-gear.
	Figure A
	Figure B

Limited-Slip Differential

The original differential that came standard on the 1962 roadster was an open differential with a 3-to-1 gear ratio. By installing a limited-slip differential, with a 3-1/2 to one gear-ratio, we are able to improve the car's traction and acceleration. Whereas the open differential only supplies power to one rear tire (the one with the best traction), a limited-slip differential supplies power to both rear tires.

Steps:

• With the T-bird on the lift, remove the hubcaps, lug-nuts and wheels from the vehicle and pull the left and right axle-shafts from the vehicle. For this job, it's best to have two people working together since the differential components are heavy and can be hard to handle if you're working alone.

• Once both axle shafts have been removed, access the differential by removing the two U-bolts holding the driveshaft to the differential yoke (figure A). Remove the U-joints on both sides, then carefully lower and remove the driveshaft and universal joint.

  Note: This procedure is essentially the same as the one that was performed earlier when changing the universal joints.)

  Important: Either hand-tools or an air-powered socket-wrench can be used to perform this job. However, if you do use pneumatic tools, use caution to avoid stripping threads when removing and replacing fasteners.

• Once the differential-housing nuts are removed, the differential can be pulled. Use a catch-basin to collect the gear-lubricant when the differential is opened. With the nuts removed, the jack-stand can be twisted to pull the differential away from the axle-housing, thereby cracking the seal. About 2 quarts of gear lubricant will likely drain out (figure B).
  
• Once the differential is drained, lift it off its studs and carefully lower it from the vehicle. Use caution as the differential itself may weigh as much as 100 pounds.

• With the differential removed, use clean rags to wipe out the housing and clean away any remaining gear lube.

• Remove the old differential gasket, then carefully scrape and clean away any remnants of the old gasket that may have been left behind (figure C). If the surface is not cleaned thoroughly, a leak may result after the new differential has been installed. A razor-knife scraper helps with this process.

• Spray brake-cleaner inside the housing and around the lip (figure D), and allow it to remain for a few minutes to loosen any residue. After the cleaner has been allowed to soak for a few minutes, clean the surface again using fresh rags.

  Figure C

  Figure D

  
  
• Once the surfaces are cleaned thoroughly, prepare the differential housing to receive the gasket by spraying on some spray gasket-adhesive. The adhesive will secure the gasket in position so that it doesn't shift during the installation of the differential. Also spray the new gasket with adhesive on both sides of the gasket.

• Once the adhesive has been applied, carefully position and seat the gasket (figure E). Press the gasket down securely to complete the seal.

• Spray a light coating of the adhesive on the differential face, then carefully lift the differential into position (figure F), making sure that it seats properly on the axle-housing studs. Again, use caution as the differential may weigh as much as 100 pounds.

  Figure E

  Figure F

  
  
• Reinstall the securing nuts and hand-tighten. Once they are all on, you can use a power-socket to tighten them down to snug (figure G).

• Then go back and make sure that each nut is tight using a hand-tool (figure H). Avoid over-tightening, since making the nuts too tight could split the gasket and result in a leak.

  Figure G

  Figure H

  
  
• Reinstall the driveshaft by slipping the front end of the shaft into the transmission housing first, then placing the rear U-joint in to yoke.

• Reinstall the U-bolts and tighten their securing nuts (figure I).

• Reinstall the left and right axle, inserting each carefully and adjusting until you feel the splines seat in the differential. Secure the axles by tightening down the bolts (figure J).

• Reinstall the brake drums and wheels. Secure the wheels by tightening down the lug-nuts.

  Figure J

  Figure I

  
  

  Figure K

• The final step is to fill the differential with gear-lube (figure K). Open the differential fill-plug, then add enough gear-lube to fill the chamber up to the hole where the plug was installed. Once the gear-lube has been added, reinstall the fill-plug.
  

RESOURCES :

Classic Car Restoration Guide: The Complete Illustrated Step-By-Step Manual
Model: 1850108900
Author: Lindsay Porter
Order this book from Amazon.com
Haynes Publishing

The Complete Idiot's Guide to Trouble-Free Car Care
Author: Dan Ramsey
ISBN: 0028635833
Alpha Books

Auto Repair for Dummies
Author: Deanna Sclar
ISBN: 0764550896

Classic Car Restorer's Handbook: Restoration Tips and Techniques for Owners and Restorers of Classic and Collectible Automobiles
1557881944
Jim Richardson
(November 1994)
To order this title from Amazon, click here.
H.P. Books

GUESTS :

Keller Wallace
Keller Wallace Street Rods
Volunteer Street Rod Association
Knoxville, TN