T-LOK DIFFERENTIAL PERFORMANCE REBUILD



Disclaimer: this is NOT a FORD approved procedure,

I'm just documenting the way i learned to do it!

Your assembly experience and results may vary.



Parts list:

Ford T-Lok Clutch Pack replacement kit (F5AZ-4947-BA) containing:

2 clutch packs (6 clutch plates, 8 drive plates)

1 pinion shaft lockbolt

1 4 oz bottle of Friction Modifier (C8AZ-19B546-A)

2 0.025" shims

2 0.030" shims

2 0.035" shims

2 0.040" shims

2 0.045" shims

1 instruction sheet

Cost: around $60 from the local Ford Dealership.



2 bottles of Mobil 1 75W-90 hypoid gear oil: $15



Rear axle cover gasket and sealant: $15



Tools required:

Slide caliper to measure the height of the old and new clutch packs.

Feeler gauges to check axle end to pinion shaft clearance during reassembly.

Assortment of standard tools

Ford service manual for disassembly and reassembly reference (optional)



Before you begin, you should soak the new clutch plates

in gear oil for at least an hour.



1. Remove rear wheels/tires and brakes from the axle.



2. Remove the rear axle cover and let gear oil drain into a pan.



3. Rotate and position the diff to gain access to the pinion shaft bolt.



4. Remove the bolt and pinion shaft that runs down the center of the diff.



5. Push the axles in to remove the C-clips, then remove the axles.

   (be careful not to damage the seals at the end of the axle tubes)



6. Remove the S-spring between the side gears.



7. Rotate the side gears to move the pinion gears out of the diff case.

   (don't lose the bearing cups that come out with the pinion gears)



8. Remove the side gears, plate stacks, and shims from each side.



9. A new stack of clutch plates and drive plates will need to be

   assembled using one old clutch plate from the original stack.

   (measure the height of the old stacks for reference first)



The standard plate setup in each side of the T-Lok is:



	CDDCDDC (C = clutch plate and D = drive plate)



For tighter lock-up, each new stack should be assembled like this:



	CDCDCDC



Typically these new and slightly thicker modified plate stacks only allow

the .025" shim to be used on each side, as the larger shims are too thick.



9. Install the new plate stacks and shims along with the side gears.

   Then rotate both pinion gears back into the diff case at the same time. 



10. The S-spring would normally be reinstalled at this point, but is left

    out to reduce understeer during corner entry/exit in autocross racing.



11. Reinstall the axles, C-clips and pinion shaft. 



The thicker plate stacks will not allow the pinion shaft to go back in, but

there are three things you can do at this point to get it to go back in and 

maintain the normal range of clearance specifications:



	1. file/grind/machine the ends of the axles

	2. file/grind/machine the sides of the pinion shaft

	3. file/grind/machine the C-clips



The C-clips were modified because they would be the cheapest thing to replace

if ruined.  Approximately .010" of material was removed from each C-clip

(original thickness is .150") to get the pinion shaft back in within the 

range of clearance specs (.005" to .030" between the axle ends and shaft).



12. Install and torque the new pinion shaft lockbolt supplied in the kit.



13. Reinstall cover with new gasket and sealant, and let cure for 24 hours.



14. Refill axle with Friction Modifier supplied in kit and new gear oil.