Hope someone can give me some troubleshooting advice. My D7E (SN 48A9768) is slipping under a load. First noticed a whine in the Transmission Hydraulic pump for a few minutes after start-up a couple years ago. Then some time later it started taking up to 5 seconds to start pulling after it was first started up, but then it would push strong all day long. Finally, a few months ago, it all of a sudden stopped pushing under heavy load. It pulled enough to get it back to the shed, but I parked it and used my D7F to finish the Farm land clearing job I was working on. I have time to work on it now and need to get it fixed before I start clearing again this fall because I use it with a heavy root rake for clean-up work. I'm hoping it is a pump or suction problem since the pump whine was the first thing noticed. I read in another thread that if I remove the plug on the top of the pump that the gauges should read somewhere in the range of 300-360 psi. Can anyone share any experiences with similar problems or provide troubleshooting steps. Thanks.

It will take few minutes to build up pressure after start up, you should let the machine warm up and circulate oil before moving anyway. Check the pressure on the pump, some whine is normal but may want to open pump and check things. If it still moved some it sounds like the spring broke on the modulating relief valve in the transmission control valve.

Have you checked the magnetic screens and filter to see what material is in them if any. There could be a clogged filter or screen, maybe pump is on its way out, if you have low pressure, be wary that you may have transmission clutch slippage, a definite no no that will finish up being expensive if allowed to continue. You could also have problems with the torque converter, you need to start a process of elimination of the various failures.

Wombat

Thanks for the replies. I've not been able to start troubleshooting yet, but plan to start this weekend. I planned to check the magnetic screen and filters first. I don't mind pulling the pump, but would like to put gauges on it first. What pressure should I expect from the pump top plug opening? I'll let you guys know what I find. Thanks for the help.

Hi D7EF,
pressure at the pump should be around 300 to 320 PSI measured at engine High idle speed.
Cheers,
Eddie B.