One for Stellan
 

I believe the truck is a Chev. What is the artillery tractor?
Bill

Massey Harris..
 

..looking grill and hood but I doubt it.
Sean

Pavesi
 

If I remember right the tractor is an Italian-made m/28 Pavesi. The gun towed is a 7,5 cm AA gun m/27. The staff car is marked A 9.

A 9 = Kungl. Karlsborgs Artilleriregemente (9th Arty Regt) wich was an AA Arty Regt.

Picture: Pavesi tractor with 7,5 cm AA gun m/00-17.

9th Artillery Regiment
 

The regiment was formed 1st January 1928. Looking closer on Bills picture in the first post I have to make a few corrections.

The tractor is not an original Pavesi m/28 but the Swedish built (NOHAB) version m/28 F. The gun should be a ptototype m/29 wich came in series-version as m/30. Max speed 25 km/h.

The rekognoceringsbil (recce car) could possibly be built on a 1929 A-Ford chassis.

Picture: NOHAB tractor m/28 F with 7,5 cm AA gun m/30.

A-Ford
 

For comparison. Here is a Ford A 1930.

ID please
 

This recce car seems to be of 1930/ies vintage. What type.

Stellan:
You are, of course, correct, the staff car I posted at the top picture is a Ford, not a Chev.
Your last picture appears to me to me an early 1930's International Harvester. The bonnet design and the maker's name plate on the bonnet are very typical of IH vehicles of that era.
Nice shot, by the way.
Bill