My Ford 555A has a plugged up tranny cooler which is part of the engine radiator, my questions are: can i use low p.s.i from my air compressor to remove debris or if it cant be cleared out can an external tranny cooler be used?
I assume that it is plugged internally. You might be able to blow some debris out by blowing opposite to the normal oil flow. Better results would come by reverse flushing, hook the inlet hose to the outlet side of the cooler, make up a hose to hook to the inlet of the cooler and in to a clean bucket, just run it for a few seconds or you will pump the trans dry. Check the stuff in the bucket. Transmission coolers normally don't plug up unless there is a problem in the transmission system. Check for rubber (hose liner material), Clutch material, or metal. also cut open the transmission filter to see what is in it. First, how did you determine that the cooler was plugged in the first place. Normally that is done by comparing inlet pressure to outlet pressure, not sure exactly what spec is for your model but guess that it should be around 15 PSI at 2200 RPM. If you are having a heating problem it may not be the cooler, could be internal leakage in convertor, worn transmission pump, leaking seal rings, slipping clutches.
Only a guess found oil leaking from inlet/outlet going into top of transmission, also under a load going forward gets hot going into trans. cooler, also found a collapsed inlet rubber hose. I do have manuals on this backhoe just dont have anyway to psi test yet. I will try your first suggestion on reverse flushing and check filter after i replace the collapsed hose. Thank you for your input. Iam hoping that this is the problem not the more difficult, such as internal leaking clutch slipping etc.