I am looking at a mid 80'sd 150 with minimal rust that is a 225 with a 4spd od. Are these transmissions a reworked NP 435? I occasionally pull a landscaping trailer that is under 2k lbs loaded.
Looking for better fuel mileage than my 2001 2500 5.9.
It has vent windows, something I have missed.

 

The 5.9 is a bit of a hog. You'll be getting better mileage for sure. I had one like that once and it pulled pretty good. It depends on your rear end ratio. I think there were two manuals in them. A unit with a plate on the side was the A833. If it had a plate on top, it was the NP435 but there were two versions. A regular low range and a Granny low with like 6.30 or so gearing in first.

 

Dead Dodge garage gave a video out on why not to think of towing with an 833 with od. The counter-shaft is not supported by a bushing, or bearing. Just the aluminum housing in the ones he tore down.
The housings can get hogged out.
I guess that is why they were largely restricted to the six cylinder engines.
Most of the transmissions (import) that I remember having torn down had bearings on both ends of the counter-shaft.
Somebody else saw the ad and showed up with money first. Thanks for getting back.

 

No, it's a reworked 833.

The OD evolution of the NP435 is the NV4500.