51 dodge pickup question

[Greeley and son]

Fluid drive on 51 dodge pickup. Will a 4 speed from a
non fluid drive work on a fluid drive? Right now 218 engine with fluid drive 3
speed. Do I need to switch bell housing at the same time?

[Rusty_OToole]

Fluid Drive needs a special trans with long input shaft. Some use a 3 speed manual trans, some use an M6 self shifting 4 speed.

Can be changed to a manual 3 speed if you have trans, clutch, bellhousing, flywheel etc. All the 3 speed stuff bolts on.

By the way the 3 speed fluid drive trans is not rare, it was standard equipment on deluxe Dodges and cheap DeSotos and Chryslers for years.

[Greeley and son]

Thank you for the info. I have a question about the crank shaft. The fluid drive bolts on crank shaft and the manual fly wheel. The non fluid drive has threads in crank and the fluid drive has studs with nuts. My question is do I have to thread the crank shaft end? Thanks again.

[Rusty_OToole]

There was a design change at some point. The older models used nuts and bolts, the newer ones had threaded holes in the crankshaft flange.

The main problem is that they moved the flange closer to the engine when they did this. The bellhousing was also shortened. And the position of the starter changed.

The later model does not have room behind the flange for the nuts.

You will need to measure all these things and figure out how to fit them together.

You should not need to thread the holes. Use fine thread grade8 bolts and be sure the shoulder of the bolt goes all the way through, so the threaded part is not taking the shear. You will need to get longer bolts and cut off part of the threaded end to get them to fit.

[Greeley and son]

thanks again for the help.

[c49er]

I have never seen a 218/230 Car or truck crankshaft that has been threaded from the factory. The 218 has a non threaded crank 4 hole flange. The 230 is an 8 bolt crank flange. Fluid couplings have 8 studs that fit to the crank. The 218's use 4 special bolts installed from the main cap side that go rear ward into the flywheel. To remove them- the pan and main cap need to come off. I have seen regular bolts and nuts used to attach the flywheels in the light duty dodge trucks.
If you can find a fluid drive 4 speed as I recall your bell housing will accept it. You might have to drill 1 or 2 mounting threaded holes. I think the bosses are already there too. I have a 4 speed fluid drive trans but will not ship-sorry!
Bob