Posted by CSCameron [172.68.46.98] on Monday, December 26, 2016 at 16:18:14 :
In Reply to: Re: Swapping a NP420 to NP435 posted by Keith in Washington [108.162.246.92] on Monday, December 26, 2016 at 12:39:49 :
Keith is correct, the crash box transmissions were "up to" or "after", not NP420. The civilian NP420 (56 and Up) will not mate up with your early bell housing. However, the later civilian NP420 and its bell housing will bolt up to the 230, but you have to pull the motor to do so.
ALL M37 transmissions have the same bolt pattern as the WWII and early FFPW (46 to 55) bell housings. However, the later model "M37B1" NP420 transmission is the best of breed for the three M37 variants.
This is the easiest way to get a synchro NP420 swapped into your truck. It will bolt up to your existing bell housing.
The civilian NP420 PTO will bolt up to the B1 transmission, the crash box PTO will not. Also, the guts of the B1 NP420 will interchange with the civilian NP20, just the cases are different.
You will have to get a late NP420 (56 and up) FFPW transmission cover and passenger side floor board. But it will look stock.
I know all of this because I just went through it on my 55 FFPW. Works great. Sorry, I can't help with the NP435.
Clark