PTFE (Teflon) coating for transmission?

[mike1180]

We used to take our locking hubs on our 4X4's (and other parts) and soak them in Slick 50.
This gave them a super thin coating of PTFE (Teflon) that was very resistant to wear, and made them move much smoother.
We did tests and we had to sand the coating to get it off.

I haven't had to do any transmission work on my busa yet, but when I do I was considering taking the final product and coating the entire assembly with PTFE (Teflon), by soaking it in Slick 50 or such.
There are some favorable articles on the net about the benefits of just such actions.
ie:

NASCAR - Teflon Tricks

Teflon-coating parts such as the crankshaft, transmission gears, and the ring and pinion sheds excess oil and eliminates rotational mass.
Today I promote running the lightest oils possible in a Teflon-coated engine, transmission and rear end, because race cars run cooler and stronger."
Total cost to coat all the essential drive train parts in a NASCAR Nextel Cup car? About $2000.
So if any of the DEI cars run well during this year's Daytona 500, now you know why - thanks to Teflon, these cars are just as slick inside as they are aerodynamically.

I would never use that stuff in the motor, but for a transmission, it should work well.

Any thoughts?

 

[dadofthree]

Been around a long time. i can remember them bringing the engine around and draining the oil and letting it run for hours after slick 50

 

[FanaticalKilla]

As long as Slick 50 doesn't have any additives that will glaze the clutch..........

 

[AJAY]

As long as Slick 50 doesn't have any additives that will glaze the clutch..........

Yep, that's what I would be afraid of.

I would also think that the manufacturers would do this if it had proven benefit for the long haul. Maybe the racers use it because it gives advantage for one race?

 

[shadetree57]

If the coating stays on the gears and doesn't transfer to the clutch assembly then I would think it'd be ok. I probably wouldn't take the chance for fear of having to do another rebuild on the transmission. If you try it let us know how it turns out.

 

[Mr Bogus]

kind of interesting... I would agree with the clutch pack issue.. I guess you need some information about how well the product is going to stay put on the gear sets.. in a captive environment like a transmission, there is no place to go.. in a bike motor? everywhere to go and again, the only bad place would be the clutch pack..

I would start checking with the Harley techs, Ducati Techs and see what they know about this.. as they do not have the clutch issue to worry about, if there is an advantage "worth" pursuing.. seems they would know huh?

By "worth" I mean the benefits are apparent enough to go to the trouble.. I would guess you might not notice anything at all.. I do know that the Gen2 bikes have an "extra" oil supply to the transmission.. maybe that is more beneficial?

 

[mike1180]

Thanks guys!
The coating will wear off, but that is the idea.
With the coating there is no direct metal to metal contact, and the surface of the coating is much smoother and has less friction than without it.
It is a chemical reaction that coats the parts, and any of it that wears off would be picked up by the oil filter, just as any part of the gears that would be wearing off without the coating.
Here is a study of how it wears off:
The conclusion is on the last page if you don’t want to read the math, and seems favorable.

http://www.me.gatech.edu/itzhak.gre...imentalAnalysisofWear...byJacksonAndGreen.pdf

It just occurs to me that if the gears, shift forks, and shift shaft are coated, the gears will move easier when you shift, and if the areas where the gears touch each other are coated, they will not wear as quickly.

 

[AJAY]

The conclusion is on the last page if you don’t want to read the math, and seems favorable.

http://www.me.gatech.edu/itzhak.gre...imentalAnalysisofWear...byJacksonAndGreen.pdf

It just occurs to me that if the gears, shift forks, and shift shaft are coated, the gears will move easier when you shift, and if the areas where the gears touch each other are coated, they will not wear as quickly.

I skimmed the technical paper. Looks like solid work. The geometry of a thrust washer applies, well, to a thrust washer. Although the load is noted as asymmetric, this is still a rotational system with the washer free to reorient itself on the shaft. You also see the transfer of material from one portion of the washer, redepositing on another portion of the washer via microwelding (which is what would happen on a standard bronze washer on steel).

I do not think this geometry would apply to shift forks and gear engagement dogs which see both sheer and impact loads on irregular, interrupted (not circularly symmetric) surfaces. It is likely that the impact load, being so high, would quickly wear off the teflon coating. But I'm only speculating.