Sure, keep it. These are fun trucks, much more drivable than most military vehicles. The 404's are even rated at 59 mph, a reasonable speed. But, as someone said, they are low powered so patience is required.
The stuck clutch will probably come loose if you do (partly) as suggested, start it in first gear and drive around, checking the clutch occasionally. Please don't run into the immovable object though. What happens is the clutch material will peel off the disc and you'll for sure have a repair then. The normal clutch disc has typical friction material, but behind/under the friction material is a flat metallic spring, making the clutch very pleasurable to drive, but also making them easier to peel.
If all fails trying to get the clutch disc loose, then the easiest way to change out the clutch is to pull the radiator, disconnect everything off the engine, suspend the engine on the front and rear with a spreader bar, and move the engine all the way up to the grill. That gives room to pull the TOB, clutch assembly, and pilot bearing. I'd suggest replacing those, too, when you put in a new disc (if required).
I've done this tooooo many times so if you have further questions, send me a PM if you like.
Typically these clutches are not worn out. If you can get it loose then it may serve you well for many years. The weak point in the system is the TOB gets dry, but it's even possible to grease it without taking anything off except the access covers!!
[edit. I should add that there's another type clutch disc, a semi-metallic "puck" disc, but those don't stick. There were a bunch of defective pressure plates sold as surplus, too, back in the '90's and those had some metallurgy problems that allowed the actuating levers, or pivot points on the pressure plate, to break off. That's probably not an issue on your truck unless it had a clutch repair in the past. Another 'gottcha' is if upgrading from a normal disc to a 'puck' disc, the clutch disc has to be installed backwards to the manual to prevent retaining springs from wearing from contact. Lots of little things to plan for...]
Bob
I have a 1963 404 Unimog at my shop that I traded in on some work i did. it is all original and has the gas 6 cyl. in it. The top is in great shape. The troop seats are still in the back along with what looks like an original pick under the truck in the tool rack. The only major problem it has is the clutch disc is rusted to the flywheel. has anyone ever had this problem? If so how hard was it to get too? I have too many toys and I need to decide if I want to keep it or sell it. I'll try to get some pics. by the first of next week. thanks in advance for any input.
