Pro gear users please step in

[KingReptile]

Originally Posted by Chris Hill

Just curious, but what is the metrology and surface treatment difference between a "street" and a "pro" gear. I know the gear guys for over the road transmissions really like a 8620 gear with a carburized surface. Gives the "tootsie roll" effect. Hard on the outside with soft gooey center .

The pro gears are 9310 the heat treat should be pretty close to the same with 8620, carburized with probally .060 case depth.The 9310 Pro Gears will be tempered at a higher temperature to take away the brittleness .The higher the temper the softer the gear, Pro Gear i would think would be 55rc to 57rc where a street gear will be 61-63Rc .The 9310 will have a tougher core harness then the 8620 which should help with rolling over the teeth..Hope this helps

[KingReptile]

40 Coupe that black surface you blasted off that gear was a phospate coating which helps with initial break in .

[40Coupe]

Originally Posted by KingReptile

40 Coupe that black surface you blasted off that gear was a phospate coating which helps with initial break in .

Interesting.

http://classracer.com/classforum/sho...highlight=prep