Trans fluid whats best??

TRBenj wrote: Too slippery for a wet clutch transmission is what I had been told (2nd hand from PCM).

Correct. The automatic in your car or truck is not a wet clutch.

OK, to quote "Bill" from Transmission Marine in Fort Lauderdale: "I have never seen or heard of anyone having a problem running synthetics...BUT... Not one marine gear manufacturer recommends synthetic oil for their reversing gears. Dextron Mercon will be fine".

There you have it.

Again I agree with Tim. My best man in my wedding waaaay back, owned a Honda cycle dealership and has always been and still is very involved with the cycle world. He would never use nor recommend a synthetic in a wet clutch trans.
John,
How many hours do you have on the trans since you started using the synthetic? Hopefully it's not getting close to the 800 mark!

8122pbrainard wrote: TRBenj wrote: Too slippery for a wet clutch transmission is what I had been told (2nd hand from PCM). Correct. The automatic in your car or truck is not a wet clutch.

So Pete

Can you explain how an automatic works with dry clutches?

I think you need to refresh your brain cells on how an automatic works and what the fluid is for.

They use discs of basically the same material as a Borg Warner.

KenO

Hi Pete

I stick with what I said before

KenO

8122pbrainard wrote: Ken, Here's how they work.

Pete: Very informative, Well done!

After you were done filming did they let you keep the flag and that jaunty cap?

KENO wrote: Hi Pete I stick with what I said before KenO

Ken, I am admittedly ignorant on the inner workings of transmissions, so what I was told could have been misleading or oversimplified... And I could also be misremembering to a degree! What was clear was that synthetic was not ideal for PCM trans, and I took that to apply to the velvets as well. The comparison was definitely made to motorcycle/dirt bike transmissions, though it appears "wet clutch" may not be the specific common design element... Anyone who knows transmissions a bit better may school us on the specifics that make this a valid comparison- or debunk it! My information came from a source I trusted at the time, though I cannot recall who it was that gave me that info... It's been almost 10 years.

Isn't the above argument missing the point, when motorcycles are referred to we're talking about wet clutch standard tranny's, nobody really is thinking wet clutch automatic transmission for cars? The PCM's we have are closer to those cycle wet clutch arrangements than a car auto tranny. Or am I missing the point?

Thanks for all the discussion after my question, interesting. Eric Lavine would be very helpful if we could ever get him to log in again!

Once again we went along way down the wrong road The original post was 20w or ATF in a PCM trans. I remember Eric saying ATF. Motorcycles are completely different,spring pressure not hydraulics control plate pressure. Motorcycle clutches live in a completely different environment too, Many use one oil throughout the system requiring a oil that needs ZDDP for the cam and being able to resist the shearing of the transmission gears and the action of the clutch. In the 60's and 70's when I was active in motorcycles you could and we did run automotive oil in them, not having much choice. When I got back into them in the 90's I found that when using automotive oils in my Honda that when it sat for a week the clutch plates would be stuck. Switched to Honda's branded oil solved the problem.
Bottom line use a quality oil change it often. In the scheme of things it's cheap.

Ken,
I found some time since you got me going on a research/education mission and I've come up with some important differences in wet clutches as used in automotive and marine applications. So here's some opinions from an engineering standpoint. First is the fact that in a marine, there isn't the typical torque converter as in a car. The torque converter allows slip or a cushion so the primary wet clutch doesn't see all the engine torque at once. A marine see's all the torque from the beginning all the way to WOT and, as you know must maintain that torque at all times to keep the hull on the top of the water. Next the initial loading on an automotive is drastically reduced at the start via the reduction planetary gearing. A marine only sees this initial loading via prop slip.

With the automotive secondary wet clutches on the planetary reduction gear sets, they are there simply to engage the planet set to the main hub so, the hub is seeing all the torque rather than the wet clutch. The physical size of these clutches is relatively large just to clear the center hubs so they have plenty of capacity.

In my research, I also came across lots of information regarding early GM and some Ford automatics run on synthetics. Evidently they too suffered from slippage due to the low coefficient of friction with the synthetics.

I may be wrong with my ideas and am certainly open to comment.

ArtCozier wrote: Haven't we thrashed this topic to death by now?

"trashed" ?? I thought this a forum for discussion!

FWIW, our old tranny friend Eric always said "NO Synthetic" in our boat trans, IIRC for the same reason as Timmy previously noted, "too slippery".

I just changed the trans. fluid out in my mother's 05 Super Sport that has around 1400 hours. I put in synthetic fluid thinking I was making an "improvement". This boat has close to 100 hours a year put on it. I will change it out soon.

lakedog55 wrote: . I will be flushing again and going back with valvoline III and about 6 to 8 oz of lucas ,

Mike,
What's the Lucas? A "stop leak"?

63 Skier wrote: Here's a link to the Lucas page with their tranny products: http://lucasoil.com/products/transmission-products Mike, Lucas makes fine products but not sure they apply to this application. I think your idea of another fluid change makes sense, but not so sure the additive is a good idea.

David,
Your link doesn't work for me so here's another to Lucas
Mike,
What Lucas are you adding and why?