1999 953C 2ZN drive pumps sound

[lray114]

Over the last week while pushing trees, I started noticing a sound difference between the two drive pumps when turning. When turning left the right pump will be louder then what the left one is when turning right. I don't recall hearing that much difference between the two prior to this job. Coming from a 953B the pump sound from inside the cab has been hard to get used to anyway, but I really like the C model.

I've not really noticed any difference in power between the two. When up against a big tree both tracks appear to spin at the same speed. The machine travels and pushes straight and it's not thrown any codes. Im just concerned about having one of the pumps puke, and would like to catch it before something happens.

The machine has 6125 hours and appears to have been taken care of. I've had it long enough to put around 250 hours on it. I've not cut any filters open yet to see it there is any metal inside. I've got to pull another fluid sample to send it in for a comparison. Should I be worried?

 

[mikebramel]

Common failures for hydraulics are contamination, cavitation, and lubrication failure... with a lot of over lap. Not sure how that set up works specifically but I would get a reading on the charge pressure to see if it maintains under load and the charge pressure inlet making sure it doesn't fall under vacuum. Also, what is the oil viscosity and the ambient temperature and operating temperatures when this occcurs

 

[lantraxco]

Second the suggestion on checking charge pressures and suction screens if any. If the motors are variable it might need some adjustments to balance things out, and also the high pressure settings should be checked to make sure they're both the same and close to spec.

 

[Cmark]

Take the oil sample ASAP.

 

[lray114]

An update.
Sent oil sample off and it came back good. Had cat tech come out to check pressures, all pressures were perfect according to him. All gauge needles were nice and steady with no bouncing. Cut open the case drain filter and it was clean, no metal. When he was there I ran the machine in an attempt to get it to warm up to normal temps, but couldn't really get it warm by running it around. Seems to be louder when its warmed up. He ran it as well and said he didn't hear anything out of the ordinary. I checked both final drives magnetic drain plugs, no chunks just typical black dust. Gonna pull pump drive oil sample and have it checked as well.

A couple of days after having it checked, I worked it hard for 8 hours pushing trees and piling, sound really didn't get any louder. Guess I'll run it for a while and watch how things go. Thanks!

 

[Dickjr.]

I have a D39 Komatsu that is hydrostatic. When its cold it makes different sounds than when it warms up. Those 953s are pretty solid machines. I'd sample it again in a couple hundred hours and build a record. Then if its all good sample at regular intervals recommended in the manual.