Sounds like a complete steering checkup is due-wheel bearings, drag link. and tie rod adjustment. My manual says zero backlash which is probably not likely on something that old but 4-5 inches at the wheel would scare the crap out of me. I think 1/8-1/4 would be good . The manual says to check with the gear in the straight ahead position but due to wear if adjusted to zero the box most likely will bind when turning. The trick is to take out as much free play as possible without the box binding when turning. 

Hi Junky

Steve has given you good advice.

Check EVERYTHING.  🙂

Right from the king pins up.  (And wheel bearings as Steve said.)

And even make sure that the pitman arm  is tight on the shaft.  (I've seen that before.)

It's been a long time since my '29 has been on the road, but I remember taking the car up to 50 mph cruising down our crappy rural highway and not being scared at all. 

Great advice!  I will check everything first before tackling the steering box.

I've only taken the truck out three times, say one mile total and for road curves the large play makes me feel like I'm not sure if I'm going to make the turn.  But, it does.  It's important to reduce this over play.

Did anyone get the difference in play versus the wheels on or off the ground?  Did this make any sense to the possible issue?

Hello Junky,

With the weight of the vehicle pressing down on the tires to the ground, there is much fraction to overcome to steer those tires left or right when not moving. ( Power steering changes that but not applicable here.) So, all the components involved in the steering system that are loose and worn will move before you get any tire left or right movement. This shows up as steering wheel play. As you start moving the friction becomes less and left/right steering is easier. With the tires off the ground, the tire to ground friction is gone and so the steering components don't have to overcome resistance to steer the tires and don't display as much wear movement, thus less steering wheel play. If you have help, have someone hold onto a steering tire that's off the ground to resist left/right movement. You should get more steering wheel play than you would if no-one were holding the tire.  

The tie-rod ends have springs in them to reduce steering shock when the tires hit a hole or object. In addition any wear on the pitman shaft and bushings will let the shaft move up and down before the arm actually begins to move the steering arms. Finally any gaps between the pitman gear and the steering shaft gear will result in steering wheel movement that does not result in rotating the pitman shaft. The movement can be reduced but not eliminated. Some movement it engineered into the steering system. Far different than modern steering gear.

To go along with Harry and Chip, when my 38 was restored we looked at the steering and adjusted it to manual spec.. On the ground I still had 3-4" of side to side play and 0 play with the wheels in the air. There's enough play engineered into the system that you'll never get 0 play with the wheels on the ground unless you replace the stock system with modern.

My '31 had a lot of play when I got it. I adjusted all of the linkages, better but still excessive play. I read the manual about adjusting the steering box several times, but could never get it adjusted right. So I took the box out and opened it up. The PO used sticky bearing grease, so I had to clean all of that out. Once I did that, I played with the adjustments so that I understood what each did and the interplay between them. Filled the box with John Deere Corn Head grease (I think that's what it's called) and adjusted it for minimal play w/o binding at the limits. Now I have 1 - 1.5 in. steering wheel play. YMMV

Yes, John Deere Corn Head grease is a self-leveling grease that is good for steering boxes. Here's a good video about that grease: https://youtu.be/7zNhli-J0Gk

I squirted a lot of JDCH grease into my '28 steering box (using a plastic ear syringe from a Pharmacy), but then added a few squirts of Mobil 600W into the box to make sure it was a slurry in there.

Even with the oil mixed in, the slurry is thick enough to NOT leak out of the old shaft seals. 

😉  Dean