? For Those With Fluid Drive Couplers

[Rusty O'Toole]

Really even with a fluid drive and 3 spd trans, I thought that was necessary with the M5 or 6 semi-auto trans.

I guess even with the 3 spd you need to idle down , so it is not surging forward while stopped and in gear with clutch out.

When I say "idle down in gear" I mean come to a stop at a stop light and sit there with the car in gear, the brake on, the engine idling but not moving. When the light turns green, take your foot off the brake step on the gas and go.

At idle speed (450 RPM) the fluid drive will slip or maybe move forward very slowly, say 97% slippage and 3% drivage. The faster you rev it the more it grabs hold until at hiway speeds, say 2000 RPM you have 97% drivage and 3% slippage.

There is always a slight slippage because you do not have a solid connection as has been pointed out.

If you want to sit idling without the fluid drive engaged, please do not sit there with the clutch out. Shift into neutral and release the clutch. If you ride the clutch you can burn out the throwout bearing. It is not a very big or expensive part but you have to take the tranny out to replace it.

It will not hurt anything to idle in gear with the ammeter showing a slight discharge and the oil pressure low.

Now you have to use your common sense here. I am talking about 2 or 3 minutes at a stop light, not idling all night with the headlights on.

[Young Ed]

Interesting in my non fluid drive car I always sit at a light with the clutch pushed in and my other foot on the brakes if the car tries to move. On level ground clutch in only. This is also the same way I drive my 5spd 94 dakota and its up to 201000 miles on the original clutch and throwout bearing.

[Rusty O'Toole]

Do you guys think engines in fluid drive cars are slower revving because of the extra weight of the fluid coupling and fluid?

Frank

There is an old trick which I am not recommending just passing along for information. Hot rodders used to drain off up to half the oil from the fluid drive for faster takeoff. It had the same effect as a high stall speed torque converter.

Recommended fluid was Chryco or MoPar Fluid Drive oil, no longer available. #10 motor oil could be substituted.

Today we use tractor oil, TDH type, ISO 32 grade which is a little thicker than #10 oil. It would actually be better to use ISO 22 if you can find it because it is thinner. The thinner oil flows better and transmits more power with less friction.