Gary, those are some good pictures and video of 17Afarmers AG6.  Thanks for sharing.  I’m looking forward to the day the paint jobs on ours look that nice!

Thanks for the tip about the driveline.  One of our tractors was missing the “cage” to catch the driveline should this ever happen.  We are fabricating a replacement now.  Yes I recently talked to one of the original Egging Co owners.  He said best he could remember they built 50-75 tractors and several went to Australia.  He said Cat would supply them with a complete and assembled frame that was stretched 3 feet and had engine installed and they would build the rest.  He did remember that they had some challenges getting the gear shifting linkages to work correctly.  He said the AG6 was an experimental tractor to help develop and determine how the challenger rubber track machine should be built.  I can see you have put a lot of time and effort into rebuilding your tractor.  It looks very nice!  Does that AC system work well?  The factory AC system leaves something to be desired.  Our second AG6 has a condenser added down in front of the radiator and the previous owner said that helped a lot due to better airflow.  (We have yet to run that one during hot weather so we’ll see). 

The Red Dot air conditioner will freeze you out and the heater part of it will keep you very comfortable by just cracking the water valve with the pressurizer blower on. That tractor was rebuilt in Montpellier east of Turlock we are lucky to have NvB Equipment in Turlock they were very good about getting all the parts making the hoses. I think that is a 9757 unit. I think most of the people on this board worry about keeping everything original which is fine if it is only going to be showed, in my case I like pretty like anybody else but I am building them to RUN and if I have to make changes to use parts that are accessible today I am fine with that. One final thought those fuel tanks have trouble with condensation and rust and crap in the tank, I had to cut holes in the tank and spend the better part of 2 days cleaning plus we replumbed it with half inch fittings and hydraulic hose with a Wix spin on fuel filter ahead of the regular filters I know of some others that had Racor filters anything to catch the water and rust ahead of your engine filters. Mike

17Afarmer, thanks for the info on the AC units and tips about fuel tanks and filtration. We have done the fuel line upgrades on ours but have not added the Racor filter. That would be a good thing to consider. I would really appreciate some pictures of an AG6 that still has the hydraulic swing draw bar on it. I want to use our tractors for ripping and according to info I’ve learned steering the tractor with the hydraulic drawbar will go a long way to protect the rear end and finals with sustained 1st gear loads. Anyone out there have pictures or info they could share? Thanks!

Srumble384. In regard to you saying you would like to do some ripping with your AG6s, I was told when I got that thing that they were kind of a fast tillage machine not made for slow speed ripping. I know that the transmission and finals in an old 7 are quite a bit heavier, the frame and running gear in the AG6 I am pretty sure goes back to 1963 or 64 with the first D6C when they had A lot less power! I am not trying to be smart or tell you what to do just to pass along what I have picked up along the way just be careful I would hate to see you tear up a Very nice tractor. 17afarmer. Mike

Neil I have never used a hydraulic hitch but I know someone that had one built for a D8k pulling a ripper. He said it only took small adjustments to keep the tractor going straight and it worked great. Better than fighting the steering clutches on a hard pull. 
17afarmer is right about trying to pull a ripper with the AG6 you might hurt it. But I guess it depends on what you mean by ripping. How deep and how many shanks. Skinner 

It's true that the AG6 was Cat's intermediate step from the steel track ag tractor (D6D SA 5x) to the rubber track Challenger series. I located an AG6 that was being used as a parts tractor and removed the hydraulics (closed center) and installed it on my D6D SA (Open center). The AG 6 has longer swing frames than the D6D and the engine weight is moved farther forward for better balance with it's 3-point hitch. In my library I have some literature on the AG6 but don't recall exactly what kind of literature.
I am envious of you finding two of them in that condition... I can't find one!