On a 331d two speed final. The final drive barely rotates when in the air. It free wheels when you pull the machine with the boom. Other final works fine yet. Any ideas as the way to start looking?
Sounds to me like the splines on the drive shaft between the drive motor and planetarys might be stripped. If it were mine I'd drain the final drive gear oil. Look for debris, then remove the outer final drive cover and remove and inspect the shaft coming out of the travel motor. Once it's out you can also look in there and watch to see how fast the travel motor output shaft is spinning.
+1, stripped splines or input sun gear.
I got it into the shop today. And pulled the cover thay is over the motor and hydro hoses. The third line from the top, a 3/8" line was so rusted it broke when I was cleaning the area out. What hose is thay one? Case drain? How do you pull the outer final drive cover. Do I have to pull the sprocket off first. This is the first final I am dealing with. I am typically splitting equipment in half for transmissions. I know I am capable of final drive work. Might just need a nudge in the rght direction of occasion. Thanks!
No need to pull the sprocket. Rotate the final until the drain plug on the outer cover is at the bottom. Drain the oil out then you can remove the bolts that hold the cover on. The whole works might try and fall off because the bolts hold all the planetary housings on. I usually leave one bolt threaded in somewhat to avoid that.
Got off and took it to bobcat for diagnosis. Piston blew apart and the shaft is stripped.