[Phil P]

quote:Originally posted by racerjoe

you might have to check with the manufacturer for schematic for this. the bypass could be built into the assembly where your hoses go or it is internal in the pump assembly. I can't answer that. The shifting mechanism might be sticky,atf will get that way, when exposed to air and fine dirt. Maybe get some Lucas or some other brand atf oil treatment and add a little to the res. run in and out to get it into the shifting valve. Or drain it and replace the oil in the reservoir. If they work separately okay, I would look at the fluid itself

Hi

According to the Parker specification sheet for these pumps the pressure relief valve is built into the pump and returns the fluid directly into the inlet of the pump. The fluid that is returned to the reviver is only the excess created when the slides are retracted because of the displacement of the piston rod.

You can hear the pressure relief valve open when the slides reach their limit of travel and you continue to run the pump. Continued running of the pump under this condition will over heat the fluid and cause other problems.

In my case when I opened the slides Thursday morning the temperature was cool enough to have caused the fluid to contract in volume. When the slides reached their limit I heard what sounded like cavitation in the pump with the on and off sound of the relief valve. This was the pump sucking air because of the low fluid level.

When I retract the slides I will check the fluid level and service it as needed.

Phil P