Just replaced both drive motors on my 763. One of the old drives had a stripped stub shaft and the other was weak and too far gone to be rebuilt (according to the hydraulic shop). Anyway, the new drives work great but the groaning noise that was present before is still there. Noise is present only when the drives are engaged and is worse under load. Some discussions seem to indicate the inline filters may cause this, and I've replaced the one near the left drive motor but not the one at the reservoir (afraid I may rip the fitting out of the tank while trying to remove it). Could that filter could be causing flow issues thereby generating the noise?
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bobbie-g
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I'm no expert on Bobcat noises. --- Are you referring to the "case drain" filters in the 1-1/2" x 3" aluminum cases? If you're worried about messing up the tank fitting and want to check the internal filter element, you might consider just disassembling the filter in place. The end of the case with the hex cap unscrews from the body. There will be a spring inside there with the element, plus maybe some O-rings plus a round flat gasket to seal the hex cap. And you may end up draining all the hydro oil reservoir out thru that open filter. But that may be an alternative for you. --- Does your 763 make the same groaning noise when stationary, but moving either the lift arms or the bucket tilt? Same noise if only one drive motor is engaged? Or maybe you have some air in the system that hasn't worked its way out yet? --- Just some random thoughts. 
---Bobbie-G
---Bobbie-GBobbie-g, yes, it is the case drains that I'm referring to. I will try replacing the filter "in place". The groaning noise is not present while moving the lift arms or tilting the bucket. Each drive motor makes the same noise. I will run the machine some more to try to get any air to dissipate. BTW, I also have a 751 with the Peugeot engine. Can you PM me - I'd like to see if you've had the same problem I've had.I'm no expert on Bobcat noises. --- Are you referring to the "case drain" filters in the 1-1/2" x 3" aluminum cases? If you're worried about messing up the tank fitting and want to check the internal filter element, you might consider just disassembling the filter in place. The end of the case with the hex cap unscrews from the body. There will be a spring inside there with the element, plus maybe some O-rings plus a round flat gasket to seal the hex cap. And you may end up draining all the hydro oil reservoir out thru that open filter. But that may be an alternative for you. --- Does your 763 make the same groaning noise when stationary, but moving either the lift arms or the bucket tilt? Same noise if only one drive motor is engaged? Or maybe you have some air in the system that hasn't worked its way out yet? --- Just some random thoughts.
Did you do any other work to the hydraulic when doing the motors? Sometimes a bad motor can damage the pumps. Have you changed the main hydraulic filter lately?
No other hydraulic work done, but a filter change is next on the list. I assume a damaged pump would result in other symptoms which I haven't noticed.
bobbie-g
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You don't have an email adr listed in your profile. My email adr is in my profile so send me an email and we'll go from there. I don't know how to do a PM on this forum.
---Bobbie-G
