450 C 1975 losing drive power when climbing

[NIKinNZ]

Hello all I have a 1975 450 C serial number 450 CJ 271126T, recently when I am climbing a hill either in reverse or forwards it gets to a certain point (if a steepish hill) where it won’t drive any more, almost like a clutch slip feel? Could it be a clutch issue? I’m trying to find any info on the clutch on this model unsuccessfully. Any help or suggestions would be appreciated.

[Jim B]

271126 is a 1977 serial number, by the list on the FAQ Board here.

You could have clutch troubles mechanical at the engine or hydraulic in the HLR. You need a copy of the John Deere technical manual, publication # TM1102, for your 450C. There are adjustments and pressures to check. The manual will have adjustment info and diagnostic checks to go through. You want to go through the diagnostics carefully to pinpoint the issue as close as possible.

What are you using for oil in the transmission and steering clutches?

Your post will likely get move to the Late Models Board, as that is where the 350/450 and newer crawler model questions belong.

[Bobby H.]

I had the same issue with my 450c . I had no high range and would loose trans pressure going up hill. I have owned the unit about 8 years and have been using low range only. i asked on the forum and got not replies. I had read the way to check fluid was engine running. I WAS WRONG. turn engine off and fill trans oil. I filled about 3/8 inch over full ENGINE OFF and now I have high range up hill down hill and will spin the tracks in high range pushing . Have been running with pressure gauge and it has not dropped ANY pressure since I pulled my head out and filled it correctly. Hope this is your issue also.

[Jack-the-Ripper]

If the engine is bogging down you could have a fuel flow or even an air flow restriction issue. I know it seems obvious but check all the relevant filters and restriction points if that is the case.

One test is to butt up against a tree and see if you can stall your engine, if not, then clutches seem like a possibility. If you are going up hill and one steering clutch is slipping it will turn your tractor. It seems odd that both clutches would slip the same amount. This makes me think it might be the main clutch that is slipping.

When I rebuilt my 450B steering clutches, the steel plates were scratched and gouged and I just thought "they'll work well enough." What a CRAZY notion. That might work on a car, but with a dozer you want all the pushing power available. It's inane to take the whole steering system apart and then chinz out on a few parts.

Now the 450C uses oil pressure through a doughnut shaped piston built into the steering clutch to provide the friction pressure when driving. If the pressure was somehow low to both steering clutches, that might cause loss of power to the tracks under high load. I haven't been into that part of my "C" to know how that could happen. It is just static pressure holding in the clutch so perhaps a pinhole leak might cause such a problem.

Of course the main clutch is dry mechanical and could have a broken spring, loose bolts, worn or gouged disks.

What happens if you push on a tree and hold one steering brake, and then the other? Can you make each track "spin?" Hopefully others will suggest some further tests before you have to start taking things apart.

If the problem comes up suddenly I like to ask "what changed?" If it happened gradually, then "what could wear out that could cause this problem?"