New hydraulic pump and now a pressure question

[oldmetalmender]

Crawler is a 1975 JD450CJ with 6 way blade. I have replaced the 4219 engine with an upgraded 4239 as detailed in the 3rd head gasket thread. While I had it apart I found the hydraulic pump had bad splines, close to wiping them clean off the shaft. The old pump made good pressure. I made sure to get the correct gpm pump when I replaced it. Before the bad engine came out I had checked hydraulic pressures and adjusted the HLR shifting to function exactly as the manual specified. About a 1.5 second shift with 165-185 PSI and the called for 5 PSI rise then drop with a 1/2 inch push on the clutch pedal. All adjustments started with the clutch as instructed by the manual. Aside from the bad 4219 engine it shifted perfect. Flash forward to the flawless new 4239 engine and several break in hours behind me. I wanted to adjust the new engine clutch and check pressures at the test port down between the control levers and found the new pump was with an hour run time making 150 PSI at about 1000 RPM. Increasing the RPM to 2400ish made 162 PSI. The manual specifies 165-185 for crisp shifts and proper pressure. Two questions. Is the 165-185 required at idle RPM? Or is it intended to be measured at a working RPM of 22-2300ish?
Changing the pressures from the manual says to remove the right floor board and add or subtract shims under the plug. The manual does not say what specifically increases the pressure. I would assume adding shims increases pressure. Is this correct?

OK, three questions... Based on what I have described, should I get in there and change it? It seems my old pump made higher pressure and I am trying to remember if it was at low RPM or not. Seems like it was in spec idling from what I recall.
The new engine is just fantastic. It starts without even a full revolution. I just would like to verify the hydraulic pressure is acceptable. Or not.

[B Town]

Good morning oldmetalmender,

The pressure is measured at 1,500 RPM. Adding a penny under the spring gives about 5 pounds of additional pressure. And no, I would not replace the pump.

Glad to here the new engine is working well.

Best regards, Bruce

PS. I use my tool tray and vandalism guard all time. Love them

[oldmetalmender]

Thank you Bruce. I appreciate the info. If it is in the manual I missed it. Glad the parts are working well for you. I enjoyed making them. Could not have done it without you and Stan.

[77 Ford]

I guess I'm going to ask a dumb question I thought I knew the answer too. When you say you replaced the pump with bad splines I assume you're talking about the pump in front of the motor under the radiator. You then specify pump pressures in the transmission. I thought the pump up front only drove the hydraulics for the loader/ dozer and the transmission had it's own internal pump. This is why they have separate fluid compartments am I wrong?

[LeonardL]

I'm glad you asked that question because I was about to ask it as well. You are correct about the hydraulics and the HLR being separate. They are two completely separate systems. The HLR has a pump very similar to the reverser pump on a 350. It is mounted at the front of the transmission case and serves only the HLR in all 450's and the steering systems in the later 450's with wet clutches. The 400G has the same system as well.

[oldmetalmender]

Oh boy.... This is why forums are so valuable. I apparently had no idea. Yeah a little embarrassing but if I don't ask, I won't learn. So I have not had a chance to check the pressure at the 1500 RPM range. I was getting prepared to add the shim or penny to boost it up some if it is low. I know it used to be in spec. I hope hope I can keep it there. I will check the pressure and go from there. Thank you for bringing this to light. It helps me and will help others trying to get their machines in good shape.

[oldmetalmender]

Yes 77Ford, the pump up front. The splines were worn to a knife edge and ready to wipe away.

[77 Ford]

I'm glad I asked now =) Now we're all on the same page and future forum readers will understand how it all works.

[oldmetalmender]

Yes, Thank you again.