Went to look at a powershift D7E with my buddy today. He's pretty well versed with old Cats. Fluids ok. Pony and main both ran good, U/C good, blade good. Could tell it was well maintained. Went to put it in gear and it won't go forward or reverse in any gear. Mechanic comes over and opens up a little valve on the tranny just forward of the right foot pedals. After that it moved perfectly. He says the PO put it on to relieve the pressure inside the tranny. I have never seen one of these. Is this a red flag? 

 

That is the transmission hydraulic pump, it appears that it is cavitating, pump could be worn, could be sucking air (small leak), whatever it is loosing its prime, others may suggest other causes.

Wombat

Seal in the pump may be shot, could be drawing engine oil in also mixing with trans oil. O ring on magnetic filter cover could be bad also.

Thank you guys. That brings me to the next question...it appears the pump has pretty easy access. It sounds like if there is a problem it's probably right there in that area and wouldn't be a difficult repair. Would you shy away from the dozer because of that?

Problem is not neccessarily located at/with the transmission pump. Air leaking into the suction line at any hose connectors or leaking seals means belly pan off, fluids drained and refilled. I'd want the issue resolved before a deal is concluded or at least compensation in the price to have the work done.

I should have disclosed it was at an auction so it was as is. Update: it sold for $17,000. I thought the pony would have scared away more people but guess not.

my thoughts exactly Neil....that musta been one hell of an undercarriage on that unit.... that price is a hard pass!!