8.8 Traction-lok Clutch Order

[MartyU]

I'm planning to rebuild a tired and noisy Traction-Lok differential in my '04 Mustang. I have experience with the bigger 9 inch rear ends but this is my first time into the 8.8.

My question is about the ideal order of the friction and steel plates. I've found lots of info recommending changing the OEM Friction-Steel-Steel-Friction-Steel-Steel-Friction (F-S-S-F-S-S-F) order to F-S-F-S-F-S-F swapping out one steel plate for a friction plate which increases the working friction surfaces from 4 to 6 giving more locking force. The locking force is only generated where a friction plate meets a steel plate. Sounds like a great idea but requires swapping a steel plate for a friction plate. You have to buy an extra friction plate (or using and old one) for both clutch pacts and reduces the number of steel plates from 4 to 3 on each side making each plate carry more of the torque load.

What I don't get is why no one I've been able to find recommends simply changing the OEM order to S-F-S-F-S-F-S to go from 4 to 6 working friction surfaces. Same number of steel and friction plates but more locking force. Plus the first plate in the stack that sits against the smaller machined back of the axle gear. If its a friction plate not all the surface has contact.

I think I'll have to test this idea by first installing the plates in the OEM order and run it for awhile to break it in and then, when I pull the axles again to install the Cobra rear brake upgrade, switch the plates around.

Am I missing something here?

 

[MartyU]

Time expired for an edit. Think this might be clearer.

My question is about the ideal order of the friction and steel plates. I've found lots of info recommending changing the OEM Shim-Friction+Steel-Steel+Friction+Steel-Steel+Friction+Gear (F+S-S+F+S-S+F+Gear) order to F+S+F+S+F+S+F+Gear, swapping out one steel plate for a friction plate which increases the working friction surfaces from 5 to 7 giving more locking force.

Note I've used + for a working surface between a friction and steel plates, and a - for steel to steel. The locking force is only generated where a friction plate meets a steel plate. Sounds like a great idea but requires swapping a steel plate for a friction plate. You have to buy an extra friction plate (or use and old one) for both clutch pacts and reduces the number of steel plates from 4 to 3 on each side making each plate carry more of the torque load.

What I don't get is why no one I've been able to find recommends simply changing the OEM order to S+F+S+F+S+F+S to go from 5 to 6 working friction surfaces. Same number of steel and friction plates but more locking force. Plus the first plate in the stack that sits against the smaller machined back of the axle gear. If its a friction plate not all the surface has contact anyway.

 

[MartyU]

Time expired for an edit. Think this might be clearer.

What I don't get is why no one I've been able to find recommends simply changing the OEM order to S+F+S+F+S+F+S to go from 5 to 6 working friction surfaces. Same number of steel and friction plates but more locking force. Plus the first plate in the stack that sits against the smaller machined back of the axle gear. If its a friction plate not all the surface has contact anyway.

Ok, I think I may have an answer to my own question. My idea puts a splinned steel plate against the back of the axle gear instead of a friction plate. The gear's splines my stop before the steel plate can seat flush to the back of the gear. I won't know until I get it apart.

 

[7991LXnSHO]

Car Craft had an article on bench rebuilding this type of differential and included a step I had not read before. File it under DUH!

Rotate it in the bench vice, I think it was 30 times, in each direction before making sure your clutch pack/shim setting is tight enough. If I find it, I can get you the date or maybe their expert place who can tell you why stack the plates and how.

 

[MartyU]

Found that article. Good tip to break in the clutches before final shimming but I'll be doing the rebuild in car. Guess I could still do it by locking one axle and turning the other with the preload spring out.

 

[7991LXnSHO]

November 12 car Craft, page 68, TomsDifferentials.com 208 265 8111 should be able to answer arcane differential questions and provide parts.
I have had good experiences with DTS on GM cars. As the Eaton style differential even uses some of the same parts, I bet they can help next time too.