1988 ford 2120, shuttle shift, cable question

[boatmoter]

Hi all, Im a little confused on the clutch operation of my tractor, it has a shuttle shift and a single clutch, it has a cable from the clutch pedal to the lube valve, I have the service repair shop manual and the owners manual on it, still do not understand how the clutch operates, is the tractor supposed to stop when you push clutch pedal half way down? or is the clutch cable to lube valve for lubing the clutches when in neutral position only ?? 1 more question, is the lube valve and the dump valve the same component??

 

[kirkawilson]

Not too familiar with your 2120, but my 1920 has a dual plate clutch that disengages the tractor drive (transmission) on the first (top) half of the clutch 'throw', and disengages the PTO on the second (bottom) half of the clutch throw. And, according to my FO-46 IT service manual, your 12x12 shift shuttle transmission has a lube cut-off valve that is operated by a control cable on the clutch pedal that might need adjusting occasionally if the main synch gears get hard to shift. The difference in the distance at 1" beyond midpoint of clutch pedal and fully depressed clutch (distance from the cable clevis to the cable bracket) should be 3/8 - 7/16 inches.

 

[boatmoter]

Not too familiar with your 2120, but my 1920 has a dual plate clutch that disengages the tractor drive (transmission) on the first (top) half of the clutch 'throw', and disengages the PTO on the second (bottom) half of the clutch throw. And, according to my FO-46 IT service manual, your 12x12 shift shuttle transmission has a lube cut-off valve that is operated by a control cable on the clutch pedal that might need adjusting occasionally if the main synch gears get hard to shift. The difference in the distance at 1" beyond midpoint of clutch pedal and fully depressed clutch (distance from the cable clevis to the cable bracket) should be 3/8 - 7/16 inches.

thanks for your reply, mine says the same.. but Im trying to find out if the first half of the clutch travel will disengage the clutches in the transmission. I bought the tractor with hydraulics not working and the trans not working, I can pull the cable by hand from the shuttle valve and the tractor will keep going, I know it has a live pto, so this has me confused on how it works without pushing clutch all way down to stop the tractor, if clutch is fully depressed, the pto will no longer be engaged.. hoping to hear from someone who has a 2120 with shuttle to see how theirs works.. God bless and have a Blessed Christmas

 

[ptsg]

So you have a single stage dry clutch that is used on control the PTO. Then you have the cable connected to the dump valve and the clutch pedal. Once you press the clutch half way, it disengages the clutch pack by simply opening the dump valve and let fluid go to the transmission.

You have two clutch packs. One for forward and another for reverse. The shuttle level actuates the valve that selects which cluck pack to engage.

 

[boatmoter]

So you have a single stage dry clutch that is used on control the PTO. Then you have the cable connected to the dump valve and the clutch pedal. Once you press the clutch half way, it disengages the clutch pack by simply opening the dump valve and let fluid go to the transmission.

You have two clutch packs. One for forward and another for reverse. The shuttle level actuates the valve that selects which cluck pack to engage.

Thanks.. this was my theory.. but needed to be positive, now my problem has turned to WHY it still goes forward, or backwards, when pushing clutch half way down, I even grabbed the cable at the valve and manually pulled it out a little at a time until I had it fully outward, and the tractor keeps moving.. any ideas? the reason the trans would not move when I got the tractor was the shuttle valve was gummed up, I removed it and dismantled it and completely cleaner and lubed every part and valley and the trans worked great, now I need to figure out what this problem is.. Thanks for your input.. very helpful..:thumbsup:

 

[kirkawilson]

My guess is that the hydraulic pressure in the forward/reverse clutch packs is too high and its not dumping. My IT manual says that the relief valve pressure should be between 242-256 psi in both directions.

 

[boatmoter]

My guess is that the hydraulic pressure in the forward/reverse clutch packs is too high and its not dumping. My IT manual says that the relief valve pressure should be between 242-256 psi in both directions.

Thanks for your reply.. I have my pressure set at 250psi. thanks again Kirk.. have a blessed Christmas :thumbsup:

 

[grcutter]

now my problem has turned to WHY it still goes forward, or backwards, when pushing clutch half way down, I even grabbed the cable at the valve and manually pulled it out a little at a time until I had it fully outward, and the tractor keeps moving.. any ideas? .:thumbsup:

My understanding is that the the valve you refer to is the Lube cutoff spool which is intended to provide hydraulic fluid to keep the forward and reverse clutch plates lubricated.
I think that this valve is providing this fluid in all positions, F, N, and R. It only cutoffs off the fluid flow when the clutch is fully depressed and this valve is pulled fully out. When the clutch is fully depressed, the fluid is directed to the sump and not to the clutch plates.
It is not surprising that the tractor still moves regardless of this valve position. The difference would be between a hard shift (no lube flow) and a smooth shift (lube flow).

Here is a paragraph from the repair manual. Passage T is for the clutch plates. Passage D is the sump.

The function of the lube cutoff valve is to permit
pressure lubrication to the shuttle clutch packs for
lubricating the clutch drive plates and discs and the
support bushings when the tractor is under load
and to shut off the oil flow to reduce the drag
between the clutch discs to permit easier shifting
of the synchronizer when the clutch is disengaged.
A cable connected between the clutch pedal and
the lube cutoff valve spool operates the cutoff
valve to open passage T and to the shuttle clutch
when the main clutch pedal is depressed for
shifting gears. Since there is no load on the shuttle
clutch when the main clutch is disengaged,
lubrication is not required.
The lube cutoff valve spool is spring loaded to keep
the valve lube circuit open and permit oil flow to the
clutches when the clutch pedal is up.
When the clutch pedal is depressed, the cable
pulls the spool outward and the passage T is
opened by around the lube cutoff valve spool to
passage D.

 

[grcutter]

Thanks.. this was my theory.. but needed to be positive, now my problem has turned to WHY it still goes forward, or backwards, when pushing clutch half way down, I even grabbed the cable at the valve and manually pulled it out a little at a time until I had it fully outward, and the tractor keeps moving.. any ideas? the reason the trans would not move when I got the tractor was the shuttle valve was gummed up, I removed it and dismantled it and completely cleaner and lubed every part and valley and the trans worked great, now I need to figure out what this problem is...:thumbsup:

It doesn't make sense that a gummed up lube spool valve stopped the tractor from moving. But this lube spool valve is located close to the pressure relief valve. If the lube spool valve was gummed up then maybe the pressure relief value was also gummed up. Since these two are connected via a passage, it is possible that your effort to 'ungum' the loop spool valve may have also ungummed the pressure relief valve. It is not clear what steps were taken to ungum but if you sprayed some cleaner in the valve hole then maybe it reached the relief valve via the connecting passage. You could remove the relief valve and inspect it for any residual gum as I suspect this method of cleaning would not be fully effective.

 

[boatmoter]

It doesn't make sense that a gummed up lube spool valve stopped the tractor from moving. But this lube spool valve is located close to the pressure relief valve. If the lube spool valve was gummed up then maybe the pressure relief value was also gummed up. Since these two are connected via a passage, it is possible that your effort to 'ungum' the loop spool valve may have also ungummed the pressure relief valve. It is not clear what steps were taken to ungum but if you sprayed some cleaner in the valve hole then maybe it reached the relief valve via the connecting passage. You could remove the relief valve and inspect it for any residual gum as I suspect this method of cleaning would not be fully effective.

actually, it was pieces of brake pads clogging the orfices of the diverter valve and shuttle shift valve, somebody used #134 fluid in it which ate up the brake pads, has to have #134-D which is the fluid for wet brakes, once i dismantled the entire shuttle shift valve completely and cleaned and probed and blew out, the Hydraulics and the trans worked, all pressures were in specs before the cleaning? the check valve is next to the lube spool valve and I just checked it again yesterday.. this is a weird problem, I purchased the tractor with hydraulics not working, I never seen them work before I bought it.. I removed the check valve yesterday and blew through the pump inlet and it came out of the pressure relief valve, put it back in and cannot blow through it by mouth,but Im sure I could blow through it with air pressure, the return to sump valleys are free and clear all way to sump,has me stumped