RZ4623 is faster in reverse and slow in forward

[jfanguy]

RZ4623 is faster in reverse and slow in forward. I just put a new drive belt on. Any ideas? It is three years old.

 

[BlazNT]

Reminds me of the time I put the belt on the wrong side of the tensioner pulley.

 

[rphill]

My 5 year old RZ5424 is having the same problem. Google search says try purging the hydro units or unit oil may be old and need changing. I wasn't aware that the hydro oil went bad as the oil becomes less viscous, but apparently it does. Youtube may have some videos on purging.