SOS '59 881trouble

Kirk-NJ · Jun 17, 2014

This was in a non runner I picked up. ORC trans.
It's an 881. I bypassed the electric system to run
the engine off the battery and jumper to the coil.
None of the oil pressure light or other safety
switches for the trans are hooked up, don't know
if that matters?
I cleaned the screen and replaced the fluid. The
pto cable is broken in the ON position and does
spin (with force)when tractor is running.
I tested with a gauge and get zero pressure at all
three servos running thru all gears.
I'm thinking may be a defective pump. Anything
else you guys can recommend before tearing this
all apart?

Thanks, Kirk

Sean in PA · Jun 17, 2014

I may be wrong, but I thought that the PTO wouldn't engage unless the pump was working, but the clutch discs may be warped and making it engage even though the pressure's not there. But the PTO spinning at least tells you that the input splines are not stripped.

Thinking about it some more, there's a couple of possibilities:

1. The inching pedal valve is stuck open and dumping the pressure back to the sump all of the time so you're not getting any pressure to any of the servos in any gear.

2. The pump is bad plus it has warped PTO clutch discs.

Opening the top cover and servicing the control valve assembly would be my first place to start in case it is a stuck inching valve, so you don't have to split it unless you know the valve is working properly.

Kirk-NJ · Jun 17, 2014

Yea I kind of thought that was odd that I have no
pressure at the servos yet the PTO still works?
I'll be the first one to say I don't know much
about the SOS tranny but willing to learn. I've
had a couple of good SOS's that I haven't had to
do munch with execpt clean the screen and change
the Oring and fluid. I wouldn't have bought this
one knowing the SOS problems but it was part of a
three tractor trade and I figured I got to learn
how to fix them sometime.

Kirk

Larry NCKS · Jun 17, 2014

(reply to post at 12:01:03 06/17/14)

How much force does the PTO generate? If it actually will drive a load, you don't have pump pressure problems. You've got loss of pressure in the traction circuit somewhere . . . or your shifter cable or trunnion isn't functioning and your transmission control valve is remaining in Park.

Kirk-NJ · Jun 18, 2014

Larry,
I believe the pto will run a load. I tried to stop
it with a 2x4 and couldn't. The more pressure on
the wood the more it ate it up. I haven't tried
anything else on the pto.
I replaced the lower half of the shifter cable and
it seem to work as in should. I screwed the cable
into the wheel trunnion assembly, adjusted it and
It seem to have tension on it when going thru the
gears.
Could it be leaking between the lower and upper
valve body or does the operation of the pto rule
that leak out?

Kirk

Larry NCKS · Jun 18, 2014

(quoted from post at 03:27:31 06/18/14) Larry,
I believe the pto will run a load. I tried to stop
it with a 2x4 and couldn't. The more pressure on
the wood the more it ate it up. I haven't tried
anything else on the pto.
I replaced the lower half of the shifter cable and
it seem to work as in should. I screwed the cable
into the wheel trunnion assembly, adjusted it and
It seem to have tension on it when going thru the
gears.
Could it be leaking between the lower and upper
valve body or does the operation of the pto rule
that leak out?

Kirk

I would think a leak major enough to kill propulsion, would kill your PTO as well.

Kirk-NJ · Jun 18, 2014

Ok I will recheck the cable wheel and turnnion
assembly and shifter cable again.

Kirk

SOS '59 881trouble

Kirk-NJ

Well-known Member

Sean in PA

Well-known Member

Kirk-NJ

Well-known Member

Larry NCKS

Well-known Member

Kirk-NJ

Well-known Member

Larry NCKS

Well-known Member

Kirk-NJ

Well-known Member

Similar threads