NP203 questions

jason2 Veteran
I have a '75 Dodge with 440/NP435/NP203. I don't think my 203 will last another storm. I found a gm 203 in the paper.

I'm wondering if there is any difference in input gears between the 203's behind TH350/400's and the gm sticks? I don't know if the 203 in the paper was behind a auto or a stick.

I'm praying the input's are the same between the sticks and autos. Also did GM use the NP435 in the 70's? Or did they still use the SM420?

Going to call on the t-case in the morning. If it will work I hope to have it stabbed in by dark. Should be lot's of fun laying on my back in snow wrestling 150+ lbs of t-case around.

By the way the 203 currently in my Dodge has GM stamped on it, so I assume the previous owner replaced the Dodge 203 with a GM one at sometime.

Thanks in advance.


Senior Member
Fairbanks AK
Pretty sure the GM stick and auto T-cases had different input shaft. 10 spline for the stick and maybe 31 for the auto? Pretty sure about 10 for the stick though. Check advanced adapters web site, it's fairly comprehensive.


jason2 Veteran
Thanks for the help guys. Doesn't look like I'm going to get away with a simple r&r. Going to first have to pull my t-case and see what I have for an input gear. Also going to have to find out if the adapter for the gm and the dodge have the same bolt pattern.

Wish I could afford the down time to swap in a 205. I'm not a big fan of these 203's.