Hey fellows, I have a Cat 416c with a standard direct drive transmission. As I was digging today a noise started coming from the transmission. It sounded kinda like a low pitch bearing squeal or maybe like an old metal buzzer. I turned the machine off and the squeal did not stop immediately. It winded down to a stop over about three seconds. I started the machine back up and the sound started back after a few minutes. I did found out that when I put the machine in gear the squeal would stop. It would immediately start back when it was shifted into neutral. It does not mater whether forward of reverse. It only squeals in neutral. Any help?
Because it only does it in neutral it sounds like something on the input shaft. Whether its a bad clutch disk or a bearing its would only be a guess. I could also be a leak, maybe going over relief or in bypass? In neutral the pump output goes to lubing only. In gear some of that oil engages the directional clutch so it take some of the oil away. Does it speed up with rpms? what about in forward but with the shifter in neutral. The first thing i would do is change the filter and cut open the old to inspect for debris.
Yes it does speed up with the rpms. I've only tried it in forward and reverse with the floor shifter in gear. This is the same machine that I ask about a few weeks ago about a large leak coming from the transmission assess hole where you reach the torque converter bolts. It only leaks while the machine is running. I have removed the transmission twice and replaced the pump seal and flat seal and it is still leaking. I did notice that the "hydraulic bearings", I guess that's what they would be called, in the pump were worn down to the bronze. They look like a bearing race. Could this wear be letting pressure flow back toward the transmission and blowing by the seal causing the leak and noise. I plan on replacing the pump soon anyway when funds allow. I would just like to only remove the transmission one more time and would like to feel confident that a pump replacement will fix the leak and noise problem. Thanks Lee for all your Help! You are a great asset to this forum!