NP 435 help

[dbolterII]

Howdy I am attempting to replace my stock NP 420 in my '64 d~100 318 poly with a NP 435. Question: will one out of a larger truck d~300 ~ d500 work? direct bolt in... I have sourced one from a junkyard, but don't want to get stung on a little detail like wrong u joint size or something and have 200# paperweight..... I am also needing the trans to have the parking brake on the tail witch is 1965 only in np 435 if I understand correct...... andy tips advice much appreciated Thx ~d

[PwrWgnDrvr]

Negative on the larger truck tranny. They all use a 1.25" input shaft rather than 1". However, it would probably work fine if u use the larger spline clutch disk. You can swap the parking brake unit from bigger to smaller trucks.
Oh, and yes it will have larger uj yokes.

[Zpsull01]

I put a 68 d500 435 into a 66 d300 behind a slant 6. The input diameter did step up to 1.375” from 1”. There was a few things we had to do.

1. I was able to find a clutch disk from a 64 f-250 that was 11” with a 10 spline 1-3/8” input shaft. This took a handful of trips to the parts store to source. It has to have the 6 smaller springs around the hub and not the 5 larger. See images below. We had a diaphragm style pressure plate originally and when the levers would release the pressure plate they would hit the 5 larger springs. Our original clutch was a 6 spring style. If you have a Borg and Beck (lever) style pressure plate it might clear the 5 spring. I was able to find this at Napa.

2. Due to slight differences in the offsets of the hub of the clutch disk, we had to remove a small amount from the end of the input shaft bearing retainer for clearance. If I remember correctly it was something like 1/4”-3/8”. We did this in a lathe but it could easily be done with a cut off wheel.

3. We used the larger parking brake assembly that was on the larger trans. The yoke saddle for the u-joint just unbolted from the smaller trans and bolted directly on the larger trans parking brake assembly. This allowed us to use our exist driveshafts and joints.

It’s been in the truck for a few years now with no issues.

[Zpsull01]

Having trouble with the images

[dbolterII]

so I got a little more info, the tranny I found is out of a 1 1/2 ton 65 d~400 so I am assuming it has the larger input shaft and uj yokes. Wondering the cutoff for the smaller input shaft did they beef it up @ 1~ton? part number is C-96041

Thx d

[PwrWgnDrvr]

The input shaft is larger in 300 and bigger thru 68, then 400 and bigger after 68.
I know this from a 66 W300 and a 70 W300 that I parted in the last month, both of which had 435's behind 318's.

[Zpsull01]

My 66 D300 had a 1" input shaft but it was a close ratio 435 behind a slant. Not sure if that changes things.

[MikeM]

U also might be able to find a 1" dia input shaft and swap it out. U would have to know whether u have the close ratio or wide space ratio tranny to get the correct input shaft. I did something similar in my 68 w200, when I regear my tranny from close ratios to wide space. I used early 70s dodge truck with the fine spline input shaft. U used all the gearing from the 70s tranny and put it in my 68 tranny. I found the correct course spline input shaft that I needed to work with the wide space gears. That would be a clean solution if u can find the correct input shaft.

Mike M