I have delt with this problem before on Kabota excavators, and found it to be 1 hyd pump was weaker than the other. The pumps are mounted to the flywheel side of the engine, you will see 3 pumps sandwitched together, 2 pumps look the same and the other 1 is smaller. The 2 pumps that are the same size run alot of the controles and each 1 runs 1 track. You need to have a volume test done on the 2 pumps.
Lets say each pump should pump 8 gal per min, if 1 only pumps 5 gal per min then the track that is running off that pump will be slower and the other functions that that pump controles will also be slow.
Paul, June 2009
