j i case 70 series when stationary if pst left in rev

jim_uny · Mar 20, 2018

for 70 series pst, can someone explain when tractor is stationary & pst is in rev bad things happen. what happens internally to
cause this ? thanks

jon f mn · Mar 20, 2018

Parts of the transmission that are turning don't get oil unless it's moving. But that only happens when sitting still, with pto on, and in reverse. Stationary pto work is fine, as is pto work while backing. And short term work like on a big round baler is also fine. Just don't put it on a blower or manure pump and leave it like that.

451 CUBES · Mar 20, 2018

Ive asked this before, but got a couple different answers.
What I gather is - while the planetary ring gear is locked stationary when in reverse, the planet gears are turning several times faster than in forward operation. The system is not designed to oil those gears at this speed for a long duration. Especially high throttle.
What I don?t get is what this has to do with pto, as the pto shaft going through the power shift unit is spinning regardless if the pto is on or not. I suspect they indicate this being a problem during stationary pto work because simply this is most likely the situation that you would have the engine at high rpm for a long period of time.

RPS 34 experts please advise.

Thanks

jim_uny · Mar 20, 2018

when i read j i case 70 series service manual it shows oil flow in reverse so that does not make sense

1370rod · Mar 20, 2018

The PTO has nothing to do with damaging the RPS 34, the reason they say do not leave the tractor in REV while while doing stationary PTO work is because of the long running time at high RPM. When in REV I was told the PS unit is spinning at twice engine RPM. We all know the whine we hear when in REV. The unit spins so fast at high engine RPM's that it slings out lube oil. Short term this hurts nothing (like snowblowing) however left running for a long period of time(like stationary PTO work) the unit gets hot and dries out allowing clutch disc to heat and warp. Yes they do , I have repaired several tractors that were backed up to a silo and blew silage all day with the PS lever left in REV. Silo's are not used much it this area anymore so that risk is less, but now with all the large livestock confinement barns needing higher HP tractors running large manure pumps I see the possibility of these problems occurring again. This problem is completely avoidable with a careful and educated operator. Rod.

pete 23 · Mar 20, 2018

I am not an expert but worked around them for a few years after merger with IH and Case. When that RPS is in reverse several components are spinning at a much higher rate of speed. I don't know if they are pressure lubed or depend solely on splash but do know that you can weld them together if run in reverse for an extended period of time. Doesn't matter if PTO is engaged or not as you just never want to let the tractor in reverse weather moving or sitting still without putting it into neutral or forward speeds every few minutes.

You can hook your snow blower and blow your normal drive etc, just don't want to go a half mile working it backing up without a few forward breaks. Now, let the experts chime in.

jim_uny · Mar 21, 2018

thanks for explanation

jon f mn · Mar 21, 2018

Im curious why case clearly stated the warning about stationary pto work rather than just leaving it in reverse while parked. Seems to leave open potential damage if you take thge warning literally.

1370rod · Mar 21, 2018

That is a good point Jon, I think a tractor could idle all day long in REV and it would do no harm. The damage happens at the prolonged higher engine RPM's generally needed for those PTO jobs. Rod.

j i case 70 series when stationary if pst left in rev

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