NP 203 question

[Ruby]

Is there any difference between a 1/2 ton and 3/4 ton NP203? My 3/4 truck is an auto and the one I found is an auto as well but from a 1/2 ton.

[712edf]

I am going to go out on a limb here, because I am not 100% certain. I have never seen the NP203 marketed or refered to in "versions" based on truck payload. Slight differences (sline counts mainly) may be present between the ones that came in a Dodge vs ones that came in a GM truck. Ford versions were driver's side front output & therefore a somewhat different animal. And I don't know if all NP 203's had the same width chain.

I'd say 1/2 ton and 3/4 ton would be the same. I have never tore into one to find out. If you can't find a definate answer here or on one of the other 4x4 sites, ask a transmission shop.

Bucky

[Ruby]

Thanks for the info. A little more info is my truck is a '76 and the parts one I found is a '78. I would also assume that they are the same as well but I live about 4 hours from where the part is.

[Deathdeelr]

I can almost say 98.897% that you need to check the transmission it's coming off of. I haven't done anything to the 203 in my Dodge but I ran into trouble when I got a junkyard replacement 203 for my 3/4 ton Suburban years ago. The replacement had a different bolt pattern for the tail adapter and the tailshaft on the trans didn't fit the input for the t-case. The yard was more than happy to exchange it but I would assume it was from a different application. Check the trans it's coming off of.

[pieter]

The heart of a NP-203 is the same for any size vehicle or any variation with exception of mounting. There is a dodge/ford or a chevy mating surface options. A divorced NP-203 supposedly exists, but I've never seen one in person.

If you need to see the variations, look-up information on a NP-203/205 doubler box. ie: find a vendor that sells them and they have pretty good info.

pieter

[Deathdeelr]

After a quick google the scuttlebutt is the mid to late '70's F series Fords came with divorced 203's and then after '79 or '80 changed to trans mounted 205's.

[RTSrunner]

Np 203

The '78 1/2 ton would be full time 4wd.Is your '76 3/4 ton full or part time 4wd? I would think being both Dodge cases they would bolt to the tailshaft adapters the same.Not sure about any differences in MT vs auto trans cases,or do both trucks have the same type trans ?Where are you located, we are dismantling a '77 W150 in Pittsburgh, PA .
RT

[712edf]

1976 should be full time as well.

Bucky

[mmwb]

"And I don't know if all NP 203's had the same width chain."

I believe that there were two different widths, but I don't remember what year it changed. Do a search. It came up when I was working on my 76 m880 about 16 months ago.

[pwdave]

The breakover year was 1978. 78 and after had the wider chain. PWdave

[pwdave]

I forgot to mention that the 3/4 and one ton prior to 78 had the big chain, so your 76 has a small chain, the 78 half ton case has the big chain, be a nice upgrade. Dave.

[Ruby]

I forgot to mention that the 3/4 and one ton prior to 78 had the big chain, so your 76 has a small chain, the 78 half ton case has the big chain, be a nice upgrade. Dave.

My '76 is a 3/4 ton. Sounds like there are slight variations in cases but should be interchangeable. Thanks for the info guys.

[yogibare143]

You are better off finding a 79 or 80 np203. The early version had 2 1/2 in chain that looks like several bicycle chains connected side to side. The newer chain is 2 inches and has flat link's side to side. The newer chain eliminates stretch problem. Some 77's had the new style chain. The gears are different so chain will not interchange.