SMTA transmission

Anonymous-0 · Mar 19, 2014

I bought a SMTA with the transmission out, gears, bearings etc were stored in bins. I have the parts manual and another good running SMTA to look at when things do not seem right. I have the transmission back in the tractor but when I roll it forward or backward there is a noise in the transmission. If I remove the shifter and move the 1 and reverse rail about 1/4 of an inch to the rear the noise is gone. However, in this position the ball above the spring is not in one of the rail indented areas. I thought I might have the wrong rail and fork but the rail and fork have the correct part number for this tractor. Anyone have any idea of what to check?

Janicholson · Mar 19, 2014

Thinking out loud: if the rail you move is moved to the rear, it is the reverse position being changed. 1/4 inch to the rear is a large portion of its travel in to reverse. this would indicate that when in neutral, it is trying to be in a gear (Probably first) and that moving the rail rearward puts it in neutral. From looking at the diagram, it seems that three things might be involved (not at the same time) The shift fork for reverse first could be bent and putting the gears in the wrong position. The shift fork for reverse first could be out of the groove in the gear allowing it to be incorrectly placed and the gear to rattle against first on the countershaft.
The reverse idler gears could be in backwards on the shaft (less likely). Best guess I have. All of these require top removal. Jim

Rollie T · Mar 20, 2014

How can I tell if the reverse idler gear is installed correctly? From the parts diagram,( #58) I can not see which end should go in first and both gears have 17 teeth.

Janicholson · Mar 20, 2014

If the gears run true with the cluster, front to back full engagement, they are correct to the best of my knowledge. Jim

D Slater · Mar 20, 2014

End with square teeth edges on both sides of the gear toward the front. End with bevel edge of forward facing edge of teeth to rear.
If going by the # on the shift fork? 400 and 450 have the same number on the fork, but the complete part with rail is different between the two. You would be off a lot more than you are with those forks though.

Rollie T · Mar 20, 2014

Finally determined that reverse/1st gear fork was tweaked enough to rub when top deck was bolted down. After some adjustment (had deck off 3 times) everything is OK. I think whoever removed the deck several years ago bent the fork or it was bumped during the time it was in storage. Thanks for all info provided.

SMTA transmission

Anonymous-0

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Janicholson

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Rollie T

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Janicholson

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D Slater

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Rollie T

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