870 pto lube pressure and flowrate

Anonymous-0 · Jul 22, 2013

Can anyone out there tell me what the pto lube pressure and flow rate at 1800 rpm with the tractor at operating temp. Cant seem to find any info on what it should be , thanks in advance any help would be grateful.

mEl · Jul 22, 2013

There is no specific dedicated lube circuit on the pto clutch assembly, the pto is served by the same pressure that the RPS34 tranny works at 190-210 PSI. I would suspect that a well sealed PTO circuit would loose very little GPM although there are several hook seals and two piston seals and Orings so a very minor GPM loss would be expected

Anonymous-0 · Jul 22, 2013

Thanks mel, I was under the impression that the line at the top left of the pto unit when standing behind the tractor was the lube line. I am chasing a oil temp problem with the pto engaged, pulling a 15 batwing the temp wants to get in the yellow on the gauge trying to figure out if it was a low flow to the lube side. I am leaning towards a weak hydraulic pump on the the 8gpm side not pushing oil through the cooler. Another ? the tractor can be put in reverse in the fourth range on the trans not all are this way did some of the early models have this or is there a problem in powershift valve.

mEl · Jul 23, 2013

The 8gpm problem should show up as weak steering with hot oil at lo rpm. An 870 has only one line going to the RH side of the PTO housing and that is the pressure feed, the small line is a return and does not bathe the clutch pack for cooling. If you suspect pump problems invest in a man with a flometer and do a test on it and be sure. Engagement of the PTO while testing would show the GPM being used by the PTO unit.

The reverse lockout was not on all 70 series tractors and was part of the mechanical linkage, not internal to the valve, it locked out the side console linkage,

HTH. mEl

Anonymous-0 · Jul 23, 2013

Thanks mel would you happen to know what temp the transmision gauge when it goes from green to yellow would be, and what is the highest temp you would feel the rps 34 needs to run at.

Case Nutty 1660 · Jul 23, 2013

running a heavy load on the pto will raise the trans temp on a hot day 85-100 degrees they will run 3/4 the way in the green even with a clean cooler is the trans low on oil or way over full? this can also cause high temps, also make sure the 3pt hitch is cancelling as this will cause hyd heating as well, is your fan belt in good condition and tight? also make sure the oil cooler is clean I usually pull it loose to get all the build up behind it and they are very small finned and air does not always clean them as to temp I would not run it if it is in the middle to high side of the yellow but again under heavy load and a hot day the temp can get up close to the yellow with no problems as the sending units do sense outside temp as well as the oil temp we seen this on 680 backhoes when roading and extra hot days they have a term for it but I can not spell it ( + ampument temp)

mEl · Jul 23, 2013

That is not a term we generally have to deal with here but it is known as ambient temperature which is the outside temperature, they used to say that a hydraulic system will run 100 degress above ambient for instance on a 80 degree day the temp of the oil would be 180 deg. This is just an example.

mEl

Case Nutty 1660 · Jul 23, 2013

Thanks mEl you explain it much better than I did

Anonymous-0 · Jul 25, 2013

Thanks again you guys for all the info, come to find out it was a faulty gauge or sending unit. Went and bought two meat thermometers and tape the them to the hydraulic lines got in some thick tall grass and pulled it hard for two hours 145 degrees was all the temp would get to. Then i undone the line at the cooler got a quart of oil and checked it 150 degrees.

870 pto lube pressure and flowrate

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