Auto trans clutches
 

Can any of you trans guys tell me the pros and cons of two different types of clutch discs? I'm aware of the different marerials available, however they offer completely flat discs and ones that have "channels" in them whats the difference and are there any benefits of running one or the other? thanks Joe

Re: Auto trans clutches
 

Joe,
The theory is that the grooved plates offer an escape path for fluid when they are being applied. The trade off for that is less surface area. Supposedly the grooved plates will offer faster application, and slightly cooler operation. I most often use the smooth plates, as I like the surface area. Not having a data logger to test with, I cannot say one way or another which plates actually offer a cleaner faster shift. As I said, I prefer the smooth clutches in most applications, when I can get them. I've had the best luck, and the best long term durability, with the Alto Red Eagle clutches and the Kolene treated steels. I know just as many people that prefer the Raybestos Blue Plate clutches, and some also use plain untreated steels with both. Good results can be had with all of them, provided the job is done right. None of them will cure a poorly timed shift, or a serious torque capacity problem. That's about all I can offer you from about 25 years of building automatics. I should probably know a lot more, I wish I did.

Re: Auto trans clutches
 

The main reason the OEM's run grooved clutch plates is to reduce the spin losses (friction) inside the transmission when the clutch is not applied. The down side of the grooves is it allows a place for oil sit which continues to lubricate the clutch plate during the clutch apply phase. This actually causes the plate to take longer to apply. Racing transmissions are set up for super quick shifts anyway, so this is really not a problem. Once the clutch is engaged the grooves have a very small effect on the overall torque capacity of the clutch.