Hyster S80XM:
Transmission fluid in the hydraulic fluid

Fellow forklift gurus, I have a hyster S80XM, Serial: E004V03795A. Called out for a tranny slippage issue. Added 6 quarts of trans fluid, pulled the diff plug to see if it was bypassing the pinion seal as there were no transmission leaks found. Diff had 90w and no trans fluid. Sent unit back to service. Called back out for a leak 4 days later. Checked unit and found hydraulic tank vent leaking severely. Pulled hydraulic tank dip stick and hydraulic tank was over full and the transmission was barely reading on the stick.. The hydraulic fluid had a red/orange tint to it. Now since this tranny is a stand alone unit, my only guess is that the hydraulic pump seal is faulty. My question is, rebuild pump? replace pump? I also figured that the hydraulic pressure would be greater than tranny pressure therefore causing hyd oil to get into the tranny? And maybe if someone could tell me if the pump just unbolts from the tranny and pulls out or does it require more labor? I have never replace this style of hydraulic pump. So any feedback is greatly appreciated.
  • Posted 27 May 2014 01:50
  • Discussion started by LTS1
  • Florida, United States
Showing items 1 - 2 of 2 results.
Pulled the pump, pulled the seal. By the time I got the seal out it was destroyed. Put a new seal in, reinstall pump. So far so good. I appreciate the feedback. A suction on the hyd pump side makes sense.
  • Posted 4 Jun 2014 07:09
  • Reply by LTS1
  • Florida, United States
I'm thinking that a suction is created at the pump shaft when it's running, and if the seal is bad, it's pulling the trans oil out of the wet bell housing. Pull the pump and check. It shouldn't be too hard to check and replace the seal.
  • Posted 27 May 2014 06:21
  • Reply by mrfixit
  • New York, United States

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