NP435 question

[boonie]

Is the only difference in the 2wd and 4wd trans itself, the mounting bolt pattern?
I have a 4wd trans and access to an advance adapter, along with the spud shaft. But the bolt patterns don’t line up because of the A pattern I have and the adapter is the square pattern. Are all the internals the same? Could I just drill holes in the flange to match my pattern? Would adding holes in the flange weaken it? Or even tap new holes in my case?I’ve got the machining end of it covered.
Or is there more to it? And yes this is to bolt up to my Dana 20. Thanks much, Jason.

 

[GWBronco]

The output shaft has different spline counts between the 4wd and 2wd trans. The 4wd has 31 splines and the 2wd has 28 splines. To use the 4wd tans with a D20 you need to change the output shaft of the trans as the D20 is 28 splines.

 

[El Kabong]

IIrc the output shaft is also different 2wd vs 4wd. (Edit- oops, too slow)

Also be aware that there were np435s built for gm & dodge that are different on the bellhousing end. I had a guy try to sell me a Dodge version as a Ford. Novak's site has some good id info: https://www.novak-adapt.com/knowledge/transmissions/manual/np435/

 

[thegreatjustino]

The above noted differences are for 4x4 NP435s with married transfer cases. If the 4x4 the NP435 had a divorced transfer case (small driveshaft between the tranny and t-case) the transmission will work

 

[Boss Hugg]

My dad was running a T19 and decided to go to the 435. He used the 2wd version, but had the same bolt pattern differences- A pattern/square pattern. Since there was an inch difference in length between the T19 and 435, he had a machinist friend make a one inch adapter plate that bolted to the 435 case, and then the d20 adapter bolted to that.

There is not enough meat on the case of the 435 to simply drill and tap holes, and if there were, the bolts couldn't protrude into the case because a gear runs right against the rear wall of the case and there would be contact issues.

 

[Quick & Dirty]

The NP435 mated to a Dana 21 is 28 spline, with the square adapter pattern, just like the 2wd trans. The adapter won't work directly with a Dana 20 though.

The Dana 21 was a single speed case, used in the late 60's early 70's in F100's.

 

[boonie]

I knew it wouldn’t be that easy. Oh well, I guess I’ll search for a 2wd trans.
Thanks much, Jason.