I just purchased an 856 wide front diesel. It is in pretty good shape for being almost 40 years old. Here's my question........ When I have the TA on the high side and press the brake it goes to the low side. When you let off the brake it goes back to the high side. It shifts and drives fine other then that small hiccup. Any ideas? I'm guessing there is some sort of valve or bypass that isn't working correctly?