I have a d4g and I have been noticing a vibration at idle. This is a little elementary but its the only way I can describe it for you. So it goes, viiibbrAATTION smooth viiibbrAATTION smooth. Think of it as a clock. It starts at 12 lightly and gets worse till 6 and is smooth till 12. Its about about two seconds per cycle of vibration. As you speed up motor it gets faster, then smooths out about 1/2 throttle. 1300 hr machine. Any help would be great. Thank!
Harmonics come on like that, look first to the accessory components, Alt, Fan hub, and driven components for noises, shaking when running then move to anything that hangs large but essentially covered up, torque converter and drive coupling. Any smoke/changes in exhaust when comes on?
Check the engine mounts too.
Its almost certainly after motor and in transmission somewhere. I have never had any transmission like in that dozer out and don't have any knowledge about that particular one. Torque converter or drive coupling sounds like it to me. I forgot a essential piece of info also. The park brake light has been staying on and sometimes fluttering. I think ill try trans filter and oil change first to see if that helps but I don't see how it will.
A G model dozer is a hydrostatic drive. The engine runs hydraulic pumps with in turn drive hydraulic motors for the tracks. I would check the monitor panel for any fault codes before doing anything. Is there any chance that there is some warranty left on the machine?
Those park brake switches gave trouble on these models. That's nothing new. Neither is your vibration. Mine had the exact same thing going on with it and I put all the hours on it from new. Sold it when it had about 6500 hours on it. It was a steady harmonic that you could feel in the seat at idle. I never felt it at any other speed. I can't remember for sure, but there is another electrical part on the right side as sitting in the seat on the engine firewall I think that makes the park brake screw up too. You have to remove the engine cover to get to it. Seems like it's a little black box.
Thanks for the info guys. Definitely no warranty left on this machine. I will check about that box in my parts book to see what that may be and replace if it seems it could be it. I'm glad to here someone else has had the same vibration it was getting me worried. You are exactly right by you can feel it in the seat at idle but not when you are working machine.
If im thinking rite...the pumps drive off a composite drive plate. I pulled a engine on one and the drive plate splines were half or better wore out. That one had a vibe before the engine overhaul. That one got run out of coolent. After the overhual put a new drive plate in.. no more vibe.