5000 SOS oil preasure readings

Greg NE

Member
Location
Duncan, Nebraska
I have been on and off again trying to get my Dad's 66 5000 back up and going again, long story. It has been setting for too long and I have alot of memories running this tractor as I was growing up. We parked it back in the late 80's when the SOS started to act up and the shop said it had low oil preasure in the tranny and it could be several things, some not too bad but others big $$. I have it running good again so I can finally take readings off the three servos to see if I can narrow down what is wrong. This is what I found, I have preasure in all the right gears at the right servos but they are all around 150lbs with the inching pedal out except for R2 and R1 which is around 210lbs and 9 and 10 are around 130lbs and I can tell the tranny is trying to lock up so I don't leave it there for only a short time. However if I push the inching pedal down I get right at 220lbs in all the right places. I am kind of guessing on the 800rpm of the engine as the tack is not working at this time so I might be a little high. I think I have a leak somewhere after the control valve but not sure where. My shop manual doesn't really say anything about this happening in all the gears just certain ones. Sorry for long post but wanted to try and explain what was going on the best I could and am hoping one of you SOS gurus out there may have run into this problem before and can maybe aim me in the right direction. thanks in advance Greg NE
 

Wow! As an old seminary professor of years gone by would say, "You slobbered a bibful there."

I would say pushing the inching pedal down shuts off the flow to the clutches. Would guess you have multiple clutch leaks.
 
You should do all of the testing with the traction disconnect lever in the disconnected position. You should never start the engine with the traction disconnect lever in the connected position unless you are in the drivers seat to be able to control the inching pedal and gear selector. If the problem was just a stuck valve and suddenly it became unstuck you could be killed.
 
I have been doing all the tests with the traction disconnect disconnected so it won't run me over and the brakes are locked so it won't coast anywhere. It acts like it's trying to go into 2 gears at once when the preasure drops too low. Back when it started to act up I was driving it down the road and idled down at a corner and it stopped without pushing down on the inching pedal. It never gave any warning before that and was operating just fine in all the gears. Could it have blown out a gasket on the regulating valve or on one of the main preasure tubes that could make it act like that? Just seems strange that all of a sudden that all the clutch packs would start leaking at once. If I keep the rpms up the tractor moves just fine in all the gears. Thanks again for the replies Greg NE
 
The fact that it will build pressure (off the top of my head normal is 225 +/-) with the inching valve dumped tells me it's something at or beyond the control valve.

The locking up scenario (2 gears at once) is likely caused by bands applying or not releasing completely as the pressure drops. They are all spring applied in that transmission.
 
As I recall the 5000 has it"s own unique gasket between the control valve and the distributor (I think that"s what it"s called). By any chance did anyone remove the control valve at some time in the tractor"s past history and replace the gasket with the wrong one?
 
I do remember Dad having the tranny worked on a few times back in the day, clutch packs one time and the main shaft bearings another time but that was some time before it started to act up and I don"t know if they ever worked on the control valve. Dad isn't around anymore and the dealer closed long ago. I just wish the 5000 SOS had a top cover like the others so I could at least take it off and run it to see if I could see any major leaks possibly. thanks Greg NE
 

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