Jd 400a Loader Backhoe Manual
I have a 1965 JD500. You can find much info on the 400 at: They are quite heavy for their size. My 500 is near 14,000 lbs. They did not have model specific problems that I know of, but do have a few things that any 40 Yr old machine will run in to. For example, the fuel injector pump (roosa master) has parts that will explode at some point and a re-build is approx. Start it and see how the throttle sounds as you run the lever up and down, and check the floor pedal as well. Should be smooth and not tend to 'run away' in speed.
They came in a clutch model and 'powershift' model (semi-auto). The diesel is a 4 cyl 270cu inch that is very reliable. I have found parts at both Deere, and a number of used dealers nationwide.
There were not a zillion of these made (total life production of less than a few thousand), so while not difficult to find most parts, you do need to look around to get them. If you go to the Deere site, they have a great parts site with exploded views of all assemblies and availability of parts. The serial number originally was in two places. On the top of the frame on the left side, just to the left of the middle of the engine, and, directly on the rear of the tractor, in front of the backhoe assembly. Take a hard look at the one for sale and make some notes on any questions you have. Post them here, lots of some pretty smart folks that have helped me much.
Jim, I'm new to the JD400. I got mine a month ago and do have the parts, service and operator manuals. The operator manual states, 'The transmission oil pump supplies oil for the main hydraulic pump.
Jd 310 Backhoe Manual Online
Therefore, avoid prolonged disengagement of the engine or PTO clutch which controls Oil pump operation. Disengaging the clutch for long periods reduces supply of pressure oil for hydraulic functions.' It is not specific to the installation of the reverser. Again, I just got mine and I'm sure you've had more experience than me, it's just something I found in the manual.
