Posted by John W. S. son of John S. [172.69.23.28] on Tuesday, February 18, 2025 at 13:06:35 :
In Reply to: Re: 46 PW transmission swap posted by Ronald Bakehorn [172.71.30.117] on Tuesday, February 18, 2025 at 08:29:33 :
The easiest way to tell which box you have is whether it has a granny low or not. The splits are very similar in the wide 435, 420 and crash box transmissions. Basically, 3 speeds with low and usually driven in 2,3 and 4. The close ratio NP435 was an "economy" transmission for towing, hauling campers etc. There is no super low and the 3-4 split was not as drastic. It will have to be driven as a true 4 speed though.
The trucks I have driven thru the mountains either live in third screaming or really lug hard in 4th and you just shift back and forth. I don't care to do 70, but can I hold 30 in third at a sane RPM instead of 20? Hopefully a fresh 251 and the close 435 I can...