NP435 and D20 install

[Johnnyb]

Is it easier to install the NP435 and D20 assembled together as a unit, or is it easier to install the transmission/adapter first and then bolt the D20?

Been a few years and was considering my options.

THX,
-JB

 

[thegreatjustino]

The transmission and adapter are much easier to balance on the jack, and lighter and easier to move around without the D20 bolted on. The D20 is also light enough that it's pretty easy to bench press and install once the transmission and adapter are installed. My $0.02. Other opinions may differ.

 

[Broncobowsher]

The output shaft sliding out the transmission is an issue when separated. When paired you won't spill oil.

My preferred install/remove is to do engine/trans/transfer all together.

 

[thegreatjustino]

The output shaft sliding out the transmission is an issue when separated.

The adapter holds the bearing in. There's no way for the bearing and output shaft to come out with the adapter bolted on.

 

[Johnnyb]

With any luck I'll get under there Thursday and get the exhaust out of the way and then Friday I plan on pulling the crossmember with the engine supported and transmission transfer case on a jack.
I guess I'll make a call once I'm under there whether I separate them for the removal or leave them together. We all know what a p i t a some of those transfer case bolts are!
To put it back in I think I'll bolt up the transmission first, just because of clutch alignment issues being easier that way and then both the transfer case on and just deal with the bolts.
Fortunately I have a rebuilt np435 and a rebuilt d20 along with a spare adapter ready to go. Hopefully I can do it in a day because I have a run planned for Saturday.

-JB

 

[.94 OR]

I have a HF quad lift that I put a plywood deck on to support my 435/D20. I used a small scissor jack to rotate the assembly into the correct clocking. Beauty is, it would fit right up inside the dual exhaust so I didn't need to remove it. Since it is on wheels, I could use a ratchet strap to pull the assembly into place. I hope I made that sound super simple. It was not. I'm not sure what was fighting me but it took a bit to get everything exactly aligned. Also, I took a couple of 1/2" bolts with a smooth shank, cut the head off so I had about 1.5" of smooth bore available, tapered the end and then cut a notch across the top of each one for lower guide pins into the bell housing. Once the things slips in, just use a flat bit screwdriver to remove the guide pins.

 

[raleigh_bronco]

I used my transmission jack from harbor freight to install the D20 separately. It took 2 of us to get it aligned properly to marry it together.

 

[ep67bro]

I have done it with the trans and transfer case together and also separated. I just did this last year. I bought the "best" heavy duty Harbor Freight trans jack and it was worth every penny. I took them out separate and it was much easier and the trans jack that has all the adjustment knobs made it super easy to put back together. Much better than when I put that set up in there 17 years ago with a floor jack and a ratchet strap! I was a lot stronger and stupid then!

 

[Johnnyb]

I have done it with the trans and transfer case together and also separated. I just did this last year. I bought the "best" heavy duty Harbor Freight trans jack and it was worth every penny. I took them out separate and it was much easier and the trans jack that has all the adjustment knobs made it super easy to put back together. Much better than when I put that set up in there 17 years ago with a floor jack and a ratchet strap! I was a lot stronger and stupid then!

I last did this in about 1994, and I did it in a weekend of young and dumb. I've been running a junkyard np435 since then and it works but shifting pattern is loose and Granny sounds like a box marbles, more than normal straight gear whine.
Since then I've had the transfer case off a couple of times and what a p i t a if you don't remove the cross member.
I've now moved the install to Saturday and hopefully I'll be Wheeling on Sunday. I'll let you all know how it goes but it sure will be nice to have a fully rebuilt drivetrain.

-JB

 

[Johnnyb]

Well, my one day install goes to two days. Had the NP435 rebuilt to the professional shop and it looks like they did an excellent job except the case they sent back had some sort of adapter on the back, it was a block about an inch thick with one allen head bolt going from the outside into the transmission and three bolts from the inside of the transmission into the adapter. I could swear that the core I dropped off at the shop didn't have anything bolted to the back of it, but I might have forgotten.
Anyways, off came the top and the perfect gasket with lots of really tough gasket cement and out came the bolts.
Unfortunately, the three bolt holes which went from the inside to the out had been drilled so there were no remaining threads in the case of the transmission. Off to NAPA to buy helicoils and then drill, tap and helicoil the case so I could install my advanced adapters adapter.
That put enough of a slowdown on the whole process I wasn't able to finish today so on goes the D20 tomorrow.
With any luck I'll be driving her home tomorrow night!

-JB

 

[thegreatjustino]

some sort of adapter on the back, it was a block about an inch thick with one allen head bolt going from the outside into the transmission and three bolts from the inside of the transmission into the adapter. I could swear that the core I dropped off at the shop didn't have anything bolted to the back of it, but I might have forgotten

You have the 1" spacer plate to use in conjunction with a stock 6-cyl adapter to install the Dana 20 on an NP435. No longer common, but was once a somewhat less expensive way to make an adapter if you had a stock 6-cyl adapter to use.