336 hydraulic pump issues

[336DinPT-HT]

I own a 1991 336 D.

The bucket loader is moving pretty slow and at high rpm's there is a high pitched wine from the area of the hydraulic pump. The wine goes away when the bucket is being used. Any ideas? My first though was it was the pump, then reading other posts here about the pumps, it seems unlikely. The filters are all to spec and clean.

Thanks

 

[winston-HT]

Just making sure, is your wire screen been cleaned? Does the 3 point operate normal? Does the pump or engine sound loaded when it is whining?

 

[alan-HT]

Correct type and amount of hydraulic fluid? Do you understand Winston's question about the screen?

 

[336DinPT-HT]

Hi,
Thanks for your reply.

The wire screen has been cleaned. Not sure about what you mean if the pump or engine sound loaded..... Do you mean does it sound strained? The 3pt arms work fine. The bucket does operate really slow until about 10 minutes of use. After the same amount of time the whine seems to be slightly reduced as well, but not gone.

Thank you

Marko

 

[winston-HT]

Sounds a little like the fluid is wrong. Sounds a little like fluid is thinning a little as it warms. What fluid are you using? Putting a load on the engine or causing the engine to strain a little is correct.