Will pto from a sm420 work on a np205 or np203?

[OrrieG]

Or any other newer transfer case?

[DirtyLarry]

Yes, the Society of Automotive Engineers standardized power source mounting flanges (and many other things) over 50 years ago. The one you question is a SAE 6 bolt power source, which fits everything with a SAE 6 bolt cover including everything from the 60’s manuals transmissions to newer ZF manuals, New Venture, Allison and Aisin automatic transmissions, Eaton automated manuals just to name a few, as well as many new and old transfercases. There is also a SAE 8 bolt power source that is not compatible with the transmissions and tcases you mentioned for obvious reasons but 8 bolt power sources are typically only found on much larger medium, heavy duty and severe duty applications.

Be aware that even though many modern transmissions and transfercases have the SAE 6 bolt covers on them doesn’t mean they actually have a drive gear inside. For example, the Allison 1000 has an SAE 6 bolt cover but does not have a drive gear unless ordered with it. Same with some NP transfercases. Pop the cover to make sure there is a drive gear in there before getting too excited.

[OrrieG]

Thanks, I will do some research. There is a guy locally that has a pto and winch from a mid sixties 1/2 or 3/4 ton truck for sale and I was mulling it over. You are a wealth of knowledge and I appreciate you sharing.

[V30 mongo]

The SAE 6 bolt mounting of pto units is the same across the board but the internal drive gear in side of the PTO unit is matched to the type of transmission/transfer case. If you do not make sure that the PTO drive gear will properly fit your transmission you will ruin your transmission and PTO unit both. The most available PTO units in the USA are Chelsea/Parker and Muncie. Both have parts manuals and applications on line.