400 Farmall - need advice

Going to look at a 400. Gas, narrow front, no Fast Hitch. Other than obvious signs of wear and abuse, what should I look for? In particular the TA and IPTO. How do I know if the TA is good? I don"t have any experience with a TA whatsoever, so I don"t how it"s supposed to work properly. And the PTO- I guess it either enages and works or it doesn"t? Thanks for any tips you can give me. I"ve only had experience with 130 and 140 Farmalls. The big ones are a new game to me! Thanks.

The TA is easy to test. With the tractor facing down the road (clear and safe) put it in 5th gear TA back. Wit the throttle open, let out the clutch as though you were almost trying to kill the engine. It should take off forward like a rabbit. When it picks up full speed, shift the lever forward as rapidly as you can (always move this lever as fast as you can every time) the tractor will now be shifting into direst. If you have a nice quick change to direct like an automotive automatic trans shift, it is fine. Throttle down at this point or you will be going 18 to 20 mph. Could be scarry if you are not a tractor driver. If you are not a tractor experienced person have the owner show you this happening on the road while you watch.
The PTO should be tested with a pipe wrench on a suitable Pto coupling fitting the shaft.(engine off) Put on the coupling and put a big pipe wrench on it such that it is trying to turn the coupling, make sure the lever is forward and in its catch notch. A 4 foot pipe will help. With solid effort the PTO brake should hold the shaft from turning. Now move the lever to the rear and latch it in the notch. attempt to turn the PTo again with the wrench, pipe, and coupling Clock Wise only this time. IT should now turn the engine and resist slipping. if the tractor is in High gear, it will not turn the engine. If the lever is held in the middle of its travel the PTO should turn easily with little drag.
This is about as careful an eaxm as can be given with nothing attached and no thing to bale or mow. Jim

I check TAs by driving in fourth gear about half trottle and apply the brakes. If it pulls the engine down the ta and or clutch is not slipping.

Try it on both high and low.

It may be the clutch slipping and not the TA so this test is not fool proof.