Friend call me the other day to go look at a 310a john deere backhoe he is wanting to buy from a old farmers estate that has passed away. Was around 19 degrees when we arrived machine was cold started in about 6 seconds of cranking time, but as soon as machine started front pump started squealing shut it back down soon as of heard it. Owners son said try again and let it run started to squealing again for around 15 seconds while it was doing that i tried to raise loader boom was very jerky and slow, after it ran for about a minute worked fine no more sounds noted ran machine for around 2 hours everything tight and worked really well, let is set for around 2 minutes restarted no squeals from front pump everything worked good. Decided to let it set for around 40 minutes, same thing happened pump squeals and hydraulics jerky for few seconds then worked great. I think it has a clogged screen in transmission or charge pump is going bad, what do you guys think if have never had this problem but i do clean the screen out every time i change trans mission fluids in my machines. Thanks in advance
More than likley there's air leak in the suction hose or pipe which allows the pump to lose it prime. The noise you here is cavitation which is basically tearing up the guts of the pump.
Where is the charge pump in that? does the reverser feed the hydraulic pump? Judging from your posts, YOU ARE the 310A expert around these parts. At 19F (-7C?) a little squealing doesn't surprise me that much. Those JD radial piston pumps are fairly crude, not as sensitive as some other higher tech hydraulic pumps. I wouldn't be afraid of it if everything was tight. It could be a clogged screen, maybe a sticky pressure control valve? old/wrong/contaminated oil? I would guess that there would have to be substantial other damage/debris if the charge pump was worn out (seem to remember lantraxco or somebody else saying that too)
Are you sure It was a pump squeal and and not a belt squeal.
If you had read the post you would notice that is did it after it was warmed up, and yes if they would let me put my gauges on it i could tell you for sure, charge pump on those machines are in transmission.