Does anyone here know what oil to use in the Fluid-Drive transmission (the Tip-Toe/Gyromatic "4" speed?? Also, what oil to use in the Fluid coupling?? This is the fluid coupling with a single bolt/plug on it to use for both draining and filling (after its rotated 180* from the bottom for draining); NOT the fluid drive torque convertor which used engine oil pumped in from the engine. I really appreciate everyone's help with this oddball question!
A Fluid Drive is a basically a torque transfer (not a convertor) with a flywheel and clutch. It is covered in the attached truck info http://dodgepilothouseclub.com/know/B4_manual/manual.htm. The shop manual calls for checking the level of the oil in the Fluid Drive every 10,000 miles - I don't recall anything about when to change it. Word of warning, before you remove or replace the plug (when it is in the up position) stuff a rag around the hole so you can't accidentally drop the plug down into the bellhousing. Other Fluid Drive owners have told me that thin works better - ISO 22 or 32 TDH tractor fluid. A standard three speed with a long input shaft was used behind the Fluid Drive -clutch set up. Sounds like you have the less common semi automatic M-6. This transmission was used by Chrysler and given a myriad of names, tip-toe, fluid torque drive, gyromatic, truck-o-matic, etc. If it one of these, the shifting pattern is different from a three speed's "H" pattern. The M-6 transmission is a 4 speed but uses only 2 gears depending on which range is selected. Low range is good for only about 20 mph, and high range, shifts from low to drive at about 18 mph. The Imperial club website has a very compreshinsive section of the M-6 in their repair section. Should be able to find out more about servicing it there.
Off topic... Just another onna my old stories is all... I think the old 1951 232" Stude V-8 air cooled, (maybe a Ford??), 3-speed automatic used 20wt non-detergent back then if not mistaken?? I had a body perfect '48 Dodge 5 pass Coupe with a 3-speed Hy-Drive and really liked it. Car was HEAVY, flathead 6-banger had two bad exhaust valve seats, so it was kind of "clunky" to drive.. Paid $80 for it in like '71 or '72?? Oh, the mohair interior stunk... Car is sitting in Moberly, MO across from the new car dealership on Hwy 63.. I want to say that the scappers like the old MOPAR fluid couplings because they can sell them for a premium to fork-truck makers.. pdq67
Bobacuda is correct. Chrysler made a "Fluid Drive Fluid" at one time, it has not been made for years. They also recommended straight #10 motor oil but today, most guys use the TDH tractor fluid in BOTH Fluid Drive unit and transmission. The Fluid Drive unit is checked thru the top of the bellhousing. There is a removable plate on the trans hump below the dash board, on the right side. Under that is a round knockout plug, below that is the Fluid Drive. Bump the starter until the fill plug comes in view. Fill to the top or till a little fluid runs out. There must be some air space, the fill hole is located so there will be the correct amount of fluid when the car is level. Transmission is filled separately. It is like a manual trans, there are 2 pipe plugs, a drain at the bottom and a fill plug on the right side. Check by sticking a finger in the hole, if you touch oil you are OK. Otherwise fill till oil drips out. Use the same TDH fluid or #10 oil. Change trans oil every 10,000. Fluid Drive never needs to be changed, just checked from time to time.
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