1948 dodge fluid drive

Please provide the capacity of the fluid coupling/converter. Is there any special instuctions in changing the oil in this coupling ? What specific oil can be used since Mopar has not manufactured "MOPAR Fluid Drive Fluid' for years ? -- thank you for any help -- dr tino -- drtino@sbcglobal.net

10wt non detergent oil is the recommended replacement. If yours is working (you can pull up to a stop, press the brake and not have to push in the clutch) then leave it alone. There is a fill on the RH side of the bell housing. Pull the plug on the housing and rotate the convertor until the plug for the convertor shows up. open the plug and see if you have fluid at that point. If it is low, rotate the convertor to the 3 o'clock position. If fluid comes out, leave it alone. Only add enough fluid to allow that to happen. The convertor will turn on its own free of the engine. It is not recommended to replace fluid for the sake of replacement, only if the unit was replaced, or if you have a leak. That (leak) is another issue that you would have to deal with. Rob

thank you Rob -- doc

Chrysler never suggested changing the fluid. As it is in a sealed coupling it never wears out or gets dirty, However, they probably did not contemplate a service life of 80 years +.

There is a thread on this, in fact many threads. Most of us use TDH tractor fluid, ISO22 or ISO32 grade. TDH stands for transmission, differential and hydraulic fluid. ISO22 is a little thinner than the original fluid and is recommended, ISO32 is a trifle thicker but easier to get. Auto parts stores, Walmart and farm supply stores have it, less than $10 a gallon. This can be used for both transmission and fluid drive. Before we had TDH we use #10 motor oil, non detergent. This is now hard to get.

To check the Fluid Drive, there is an opening in the floor boards on the right side of the transmission tunnel below the instrument panel. Roll back the carpet and there it is. Remove the screws and take off the metal plate, underneath is the bellhousing. It should have a round tin knockout plug. Pry it out. Inside the bell you can see the torque converter. "Bump" the starter until the plug comes into view. Unscrew the plug and fill until the oil drips out. CAUTION, stuff a rag around the hole before you remove the plug, do not drop the plug inside the bellhousing or on the floor, you will be sorry.

If you want to drain the fluid look on the bottom of the bell and see if there is a removable cover plate. If there is you can turn the plug to the bottom, drain, turn the plug to the top and fill it up again. But, as I said, this is not strictly necessary.

The factory recommended changing the trans oil every 10000 miles. It has a drain plug on the bottom in the shape of a pipe plug. And a similar plug half way up the right side of the trans, this is the fill plug. Drain out the oil from the bottom and pour or pump oil in the side until it drips out. To check the oil stick your finger in the hole, if you can touch oil it is full.

There is another removable plate in the floor above the trans on the right side for testing and servicing the controls. It will make pouring the oil in the trans easier, or you can pump it in, in the usual way.

Later................

Here is another discussion of the same issue, with a different fluid recommendation.

http://forums.aaca.org/f145/chrysler-fluid-drive-type-fluid-157867.html

You better sign up for a day or two off work if you plan to drain and refill the FD coupling. Slow and teious to say the least.

I have never changed the fluid in any of my FD cars... some I've had 40 years and all work just fine.

I have seen them sometimes leak a bit after a fluid change.

I'd be careful.