JD450 Trans jdemaris Please!

The question: I have a JD 450. Not a B, not a C just a plain 450. The 1234 Transmission on the left side of the seat all works well except occassionaly when I'm going downhill say in third gear (moving to another place) she suddenly falls out of gear and if I don't catch it starts stripping. If I hold the brake and don't let it get too fast this doesn't happen. Occassionaly also I will shift that lever into second and when I let out the clutch it just sits still. I can reshift then go back to second and she does fine. First and Third work fine and so does Fourth but I really dont want to run the old girl that fast.
Are there any quick fixes for this? How much further damage am I doing? How long will it last if I am just careful to hold the brake and not allow it to do the 'fall out of gear' thing? Would it be better to fix it now or just wait till it quits?

I might say too that I'm using it a little on the farm and have dug a couple of basements here on the farm and still have one to go and two to backfill. After that I guess I dont care too much cause it will have paid for itself. I did overhaul the engine Inframe a couple years back and the tracks have about 2 inches of adjustment left yet. Has a detachable backhoe too. A useful machine that you have helped me to keep running! Much appreciated.

I will check the linkages as you suggest, and probably pull off the top to have a look when I can spare the time.

It does not have the new Neutral groove cut and since you have warned about that before, I always am sure to have the front bucket and sometimes the backhoe down tight before I crank it. I have also warned others who use it about the problem and they do the same.

And thanks again for your always patient and thorough explanations.

That being said - the four-speed range transmission is just a simple non-synchronized gear setup and it's either in gear, or it's not.
It was always sloppy and uncertain, even when new.
If you get times when the machine doesn't try to move when you let the clutch up - and you don't hear the gears clashing, grinding, etc. . . . then you might have some other problem. That could be the engine clutch -which is the most likely problem. It's just a single dry disk and pressure-plate. It also could be a linkage/hydraulic problem making the hydraulic clutch slip in the HL-R trans - assuming your crawler has the option. If you do have the HL-R -there is linkage hooked to the clutch pedal that often gets out of adjustment. What is supposed to happen is - push the pedal down halfway and the hydraulic pressure gets cut to the HL-R - and push the rest of the way and the dry engine clutch gets disengaged. All that linkage is tied together. On the floor - there is an access plug - and underneath is a threaded shaft with a nut or two on it - sometimes jam-nuts. Takes a 1/2" or 9/16" wrench. They often come loose and screw up the adjustment. Best thing is - ascertain what exactly is slipping - or not working when the crawler doesn't move. You can put a pressure gauge in the trans - and if the pressure stays up when not moving - you can assume the problem is not the HL-R. Back to the beginning - it's hard to diagnose from here. Maybe you're confident it's just not going into gear when you shift the 1-2-3-4 trans? That is common - since shifting is sloppy and uncertain - they were that way even when new(as already said). When worn, it gets worse. If that is the case, and you can eventually get it into gear and working - I wouldn't worry about it - other than looking over the linkage. It's probably just worn and sloppy. I assume that crawler spends most of its life in 2nd gear anyway - if you have the HL-R. If not, then I guess you have to shift it more often. If you really get worried about it, you might have to pull the trans- top-cover sometime and take a close look. Was your range-trans shift gate ever updated with a neutral slot sawed into it? Deere had a major lawsuit against them and were searching for every 2010 and 450 they ever made with the HL-R - to do modifications to the shift linkage.

Hey, it's the American way.
Brian