Greetings - my otherwise pristine (rebuilt undercarriage on a 10k hour) 490D was working great and quiet. Just 10 hours ago she growls in turtle, but is silent in rabbit. In either low or high drive it seems to function fine. Might this be a matter of something stuck in the one valve, causing it to 'chatter'?? Okay to use it until it becomes more defined of a noise? Thanks for your thoughts! ~ Mark
Loose gear on the low side in the final? Is the noise coming from the final? I know on our old 2650c2 link belt the 2 speed actually used 2 different sets of gears to go from low to hi. May want to drain the oil and see what comes out.
I,m probably wrong, but I think a 490d has the same running gear as a hitachi 120-1. If this is so you don,t have two track gears, the different speeds only come from different engine revs. My fiat hitachi 130-1 started to screeve at slow speeds, turned out that the oil had leaked out of the front roller and was running dry. Though the noise was coming from final drive until another person drove the machine and I walked along beside it.
Ahh, Mr. FiatHitachi - you may have solved a different problem for me! With the engine speed in work mode, when I use the propel drive in turtle, it automatically goes to idle. I thought something was awry - but I think you are correct Sir, this is how the Deere has two speeds. Now, this doesn't 'splain how it makes chatter/groan in one speed and not the other.... Fluids are up in the final drives, and the small carriers and top little roller feel great. Are you saying the front, LARGE roller (I would call it an idler) has gear oil in there somewhere?? Thanks!
Yea I should have called it the front idler. It should have oil in it, but I think it,s more like engine oil rather than gear oil. On the fh 130 there is a allen key bung that goes into the idler near the center boss on the idler. I managed to get mine screwed out and fitted a grease nipple as the seals were shot. In L mode tracks only go at idling rpm. In E mode and rabbit, tracks work at 1800 rpm. E mode and turtle as you know means idling rpm. In P mode and rabbit, tracks work at max rpm but slightly reduced oil flow. P mode and turtle, tracks work at 1800 rpm