What kind of hyd flow/ pressure does your tractor supply, and the
chipper want?
Without knowing much, it sounds like one of the following:
1. as the first person mentioned, you have an air leak, sucking air into the suction side, creating bubbles in the fluid. Doesn't show up for casual use, but for this high-volume use it comes out.
2. You have too small a size hose (or connectors) on the return from the
chipper, creating restriction/heat/ bubbling.
3. you are low on fluid, again creating bubbles.
4. The
chipper is overworking your tractor pump, creating hot oil and - bubbles.
Compact tractor might be designed for occational hyd use, while the
chipper feed is constant use. This is combining with several of the above, so as to get air flowing along with the oil, and it just builds upon itself.
On ag tractors, sometimes one needs to run a larger hose back to the oil filler cap and let the oil dump back to the tractor quickly, wthout quick connectors or other flow restrictions in the way - after the
chipper is done with the oil, you want it to run with no restrictions at all easily and quickly to the tractor sump so it can cool and settle out air bubbles as quickly as possible. Aslo, many farm tractors allow an extra gallon or 2 to be put into the sump without harm, overfilling it but this allows the oil to stay cooler, not be recycled as quickly anf overheated.
Don't know how that last paragraph applies to a compact tractor, but just for ideas....
There is some ration of how much oil is in the sump, vs how much oil flow one can use for constant use - so the oil has time to sit and recover & cool down in your tractor sump. I suspect you are near or over that limit. Any of the above issues makes it worse.
--->Paul
