JD 450 crawler loader

[cstimmell]

1970ish dry clutch machine. I did a pretty major overhaul last year on the machine. All new steering clutches, chains, sprockets, etc. Runs very strong and everything works well except I have one head scratch issue. When I'm on level ground or pointed downhill, the machine works great. If I turn it around and point it uphill, it will lose ALL drive. Nothing forward or backward. Not in any gear hi or low. I have a backhoe on it so I drag it back to level ground and everything work fine again. Any ideas on where to start? Also it will go uphill in reverse just fine.

[Jim B]

first thought is a problem with the pump pickup line such that it sucks air headed up hill.

[cstimmell]

Jim, Thanks for the response. The hydraulic tank is full, and I lose drive even on a slight incline. Also, I don't think hydraulic does anything with drive on these older machines. still searching for answers

[Jim B]

I am not talking about the hydraulic system. There is a pump in the transmission which provides the pressure for the transmission and steering assist. They are completely separate systems; the hydraulic system uses the fluid in the tank under the right armrest and basically a flooded system as the tank is above the pump. The Transmission and steering use the fluid in the transmission and the pump pulls fluid through a screen inside the transmission via a pickup tube/circuit. If there is a leak anywhere in that circuit that is above the oil level when you head up a hill you could lose flow and pressure which would let the drive clutches in the HLR slip. The fluid level will change with operating angles. Also check for loose mount bolts which might cause things to come out of line and allow slipping.

Do you have a copy of SM2064, the service manual for a straight 450? It will have info on the transmission circuits and trouble shooting. Did you check change the screen inside the transmission? Is the transmission fluid full (with a J20C rated UTHF if you don't use Hy Gard) on the dipstick.

You need to find the issue before it damages the HLR pump and or clutches.

[cstimmell]

Jim,
Thanks for the helpful info. I checked the fluid in the transmission, and it was low. Filled it up and everything is back the working normal!! I wish everything was that simple. Thanks again!