Transmission Question

[Anicola]

Hello all,

Forgive my likely simple question, but I've just purchased this truck, and I'm trying to learn more about it. I have what I believe is a 1969 D400 or D500. I'm pretty sure of the year, not so sure of the 400/500. Any way to identify that?

What manual transmission came in this truck, is it the NP435? Mine has the PTO on it for the dump bed, not sure if that makes a difference.

If this is the NP435, is a 12 valve Cummins Adaptable? I have a 1991 sitting in the back yard. The truck is in great shape, and the slant six that is in it runs. It has a mean sounding tick, but even if I were to rebuild it, I'm thinking its not going to have very much power at all. OR, has anyone rebuilt a 225, with some performance upgrades? It would be fun to keep the original motor.

Also, I think this truck has a 2-speed rear end?? The thing is absolutely massive, and there's a canister-like thing sitting on the drivers side of the axle, in the front by the driveline. If this is a 2-speed rear end, how to you switch gears? and can you shift it while driving?


Thank you

[712edf]

I think a D400 has 5 lug wheels, I know D500 has 6 lugs. Is there a VIN plate/tag on the driver's side door jamb area?

If transmission is 4 speed then its a NP435, if 5 speed then N540. If you want to swap in the Cummins then it'd be better to swap in a more compatible transmission too.

Two speed rears will have a lever/switch on the gear shifter. And I think you do shift (lo-hi) while going through the gears. Sounds like yours is 2-speed, which makes it more likely a D500.

Bucky

[712edf]

Upon further research I think yours has the 435, I don't think the 5 speed was ever put behind the 225 slant 6.

I am seeing pre 69 D400 with 5 lug wheels & some 69-up have 6 lug wheels. So I don't know, if yours is 6 lug then it still could be D400.

Bucky

[dodgeboykim]

D 400 trucks did have the 2 speed axle as an option. I drove one when I first started truck driving for work. Baaaaccck in 1976. Truck was a 69.

[Anicola]

Thanks guys, mine is a 5 lug in the front, six lug in the back. Drivers side are reverse thread too. Weird.

Bucky, you are correct in that there is a vin in the door jamb, it was covered with tape, and painted over. Verifies that it is in fact a D400.

[712edf]

Thanks guys, mine is a 5 lug in the front, six lug in the back. Drivers side are reverse thread too. Weird.

Bucky, you are correct in that there is a vin in the door jamb, it was covered with tape, and painted over. Verifies that it is in fact a D400.

Left hand threads on Driver's side is common, my W600 & W500 are both that way.
Did you run the VIN through the registry?

Bucky

[PwrWgnDrvr]

Thanks guys, mine is a 5 lug in the front, six lug in the back. Drivers side are reverse thread too. Weird.

Bucky, you are correct in that there is a vin in the door jamb, it was covered with tape, and painted over. Verifies that it is in fact a D400.

All D400's have 5 lug axles. The 6 lug axle u have in the back is from a D500 or larger and is NOT original to the truck. No truck ever left the factory with different lug patterns front and rear!