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Fieldtech59, Shop manager
Category: Construction and Road Equipment
Satisfied Customers: 111
Experience:  Construction equipment repair technician since 1986, JLG certified, Shop manager since 2006.
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I have a t870 bobcat I have been trying to work out on the

Customer Question

I have a t870 bobcat
I have been trying to work out on the left track with the right tension and completely clean but there is like a high pitch sound coming from the top of the main drive wheel when it is in the forward motion and from the bottom of the main drive when it's in reverse have checked the oil and it's fine.
It's not a grinding noise.
It first happened yesterday whilst slashing and I lost power completely in the left joystick and then the hydrolic pressure gauge was nearly in the red when I had no power in the left joystick and then it went back to normal when a regained power in the left joystick again.
then I had the automatic hydrolic shutdown come up on the computer but I turned it off before this happened.
No fault code came up have put the left hand side up on jacks and tried to get the track off but was unsuccessful in doing so.
Any suggestions?
Regards Matt
Submitted: 1 year ago.
Category: Construction and Road Equipment
Expert:  Fieldtech59 replied 1 year ago.

Hello Matt, I need to clarify some of your information. When you hear this squeal, does the machine lose drive power and loader lift/tilt power as well? Then when you let off of the drive control and loader control, does the squeal go away and power is restored to drive and lift functions?

Customer: replied 1 year ago.
It did loose all power only to the left joystick and then it was working again
All other hydrolics are working perfectly.
The soun It's only coming from the left hydrostatic main drive.
It's pret wierd
Regards Matt
Expert:  Fieldtech59 replied 1 year ago.

Ok, is this a Selectable Joystick Control machine, left joystick controls both left and right drives?

Expert:  Fieldtech59 replied 1 year ago.

I don't want to leave you hanging until I log back in tomorrow evening so allow me to throw some thoughts out there. I don't know what Bobcat machine you have, standard controls, Advanced Hand Controls, or Selectable Joystick controls, but regardless, I've never heard the drive motors on a Bobcat make a squeal noise and lose power, but that doesn't mean it can't happen, just never heard that myself, so I can't address that. Bottom rollers and idlers can make a squeal noise when they seize up, that I've heard plenty of times, and if an idler is locking down it can affect the drive on that track because of increased friction from a seized idler. But if there's nothing wrong with the undercarriage, rollers and idlers are good, in most cases when you hear a squeal on a Bobcat along with a loss of drive power it's caused by not enough tension on the drive belt, but this condition typically affects both left and right drives, loss of drive power of both tracks until you release the drive control and it recovers. I just wanted to throw some info out for you, and I'm going to go ahead and opt out of the question which will put it back on the board for others to view and possibly offer other things to look for.

Expert:  Fieldtech59 replied 1 year ago.

I suppose I should clarify myself. Although I opted out of the question, that only means your question goes back on the back on the board for others to view and possibly give their input, but I'm still here and able to jump back in if I have any other thoughts.

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