Pics of a Howard transmission in NAA

First off, on the NAA, the Howard shift handle is located on the left side of the tractor. Here's what it looked like before the tractor started coming apart.

When you split the tractor behind the transmission, this is what you'll see.

The gear reducer is bolted to a metal sheet that fits between the trans and the rear end section. It takes the place of the splined coupler that would normally be there. Here I have it held in place with just a few bolts. After you pull it out, you'll see this:

There is a sliding coupler on the driveline. It has five large lugs on the forward end and a 20 tooth gear just behind the five lug drive surface. The coupler is moved by the red fork you see.

Here is the inside of the left inspection plate used with the Howard. It is thicker than the stock inspection plate and has the coupler shift rail build into it.

This is the main unit laying face down on the floor.

If you look down in the center hole, you can see a matching 5 lug pattern down inside the unit. This mates up with the leading edge of the coupler when the unit is engaged. You can also see a 20 tooth pattern at the top of the center hole. This where the coupler engages when the unit is disengaged.

Warning! Blurry photos to follow! First the coupler.

Now, with the unit disengaged (handle back) the coupler slides toward the rear of the tractor and the 20 tooth gear meshes with the outer 20 tooth hole at the outer edge of the Howard. This puts the tractor in direct drive.

Then if you push the handle forward, the coupler slides forward and the five lug drive face engages the matching 5 lug pattern inside the Howard and the gear reduction is engaged using the planetary gears housed inside the unit. The gear reduction (according to my observation) is almost 3 to 1.

The groove around the trailing edge of the slide coupler is where the slide fork engages the coupler.

Sorry for the blurry photos. I hope someone else besides me found this interesting.

Donations gladly accepted! ;)