SMTA sometimes hanging up in a tight spot

RBTXS

Member
My SMTA will sometimes leave me in an uncomfortable position when it gets locked up in gear-- either forward or reverse. Someone told me that the problem is caused by the TA clutch hanging up. The TA has never worked since I have owned the tractor-nearly 30 yrs. Since I don't know anything about the TA, I don't know if I have been told the truth or not. What could be causing this problem, and how do I fix it? It only happens when the tractor is in a strain. I have learned to always get it out of gear when it is moving.
 
Have you tried adjusting the clutch and TA according to manual? There is step by step directions on adjustment and if the TA gets out of adjustment it makes the tractor shift hard. I suspect it would do so even if TA doesn't work as the TA clutch is still working if TA is out on the low side. I ran into this on my SMTA after putting in new clutch and not reaadjusting linkages.
 
I just went through this with my SMTA. I doubt that it has anything to do with the T/A. Mine locked in gear on a hillside and was very difficult to get back to the barn. The problem was the shifter that moves the transmission between gears. A lot of help was required through YT people. The end of the shift rod was so worn that it wouldn't shift accurately. I pulled the shift lever and built up the end of the rod with nickel rod and filed it back to proper shape and no problems since. Ellis
 
We experienced this same difficulty on a 450 Farmall. The torque has been non-functional in that tractor for nearly 40 years, thus the lever is left in the forward position. When the shifting difficulty you describe is encountered, one simply had to pull the T/A back, shift into the desired gear, release the T/A lever back to the forward (direct) position, and let the clutch out. While this may sound a bit "mickey-mouse," the 450 serves simply as a PTO power source for a grain auger or standby generator, it has belonged to another family member for the past nearly 30 years. At the time it was used more often, it was not worth sticking any money into it since the cost of a new T/A was about what the tractor was worth in good condition.
 
Binding caused by the TA and being stuck in two gears at once are two different issues.

It sounds like you have binding being caused by the TA.

Down on the left side of the clutch/ta/transmission housing are three linkages. One from the clutch pedal to the clutch throwout. One from the TA lever to the TA throwout. One from the clutch throwout to the TA throwout.

That last linkage is the one that needs adjustment. The purpose of that short linkage is to disengage the TA clutch at the same time as the main clutch.

The TA has a one-way clutch inside it that allows the gear reduction to work, and it's that clutch that binds up when the tractor settles backward slightly as you come to a full stop, UNLESS the TA clutch is also released. This is why pulling the TA lever will allow you to shift.

There is a procedure in the manual for adjusting the TA, but you may have to over-adjust a little bit to compensate for wear. Just keep shortening that short linkage until it pulls the TA throwout fully, but has no tension on it when your foot is off the clutch pedal.
 

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