1975 Sears ST/16 - No Low Range

I have a 1975 ST/16 (917.25873) in great mechanical shape except that it won't go into the low gear range. There is no grinding or any other indication that anything has changed when you move the lever into low range except that you do feel it click into position through the handle. This wouldn't even matter considering the torque of these engines except that I have a bucket loader on it with dual rear wheels so the low range is very handy for pushing big piles of dirt around with more control over slipping.

It seems to me that if any gears or shafts were damaged it would make some sort of noise when put into low range but it's just as if it's shifting into neutral. My guess is that something has failed between the hi/low shift lever and the shifting fork assembly that's preventing the low-range gear from being moved into place. However, it has no problem shifting back into high range.

If you have any experience with these transaxles, I would appreciate any ideas regarding the cause this problem. Is it possible that a linkage could be bent preventing the fork from moving completely into position?

Thanks,

D

Just to be sure;I"d jack it up,try moving shifter up and down while looking thur the crack between back plate and frame.Might need another set of hands for this.There"s a rod that slides in & out at the top of transaxle,could need some oiling or sanding with fine sandpaper.Might also be worn holes that cotter pin goes thru.Dude11

Thanks for the follow-up on my question. I think a worn hole where the cotter pin connects the shift linkage to the high-low shift rod makes a lot of sense as the culprit. Perhaps it's worn enough that the linkage is hitting the side of the frame before it can pull the rod out far enough to complete the shift.

My tractor has liquid-filled dual wheels with additional wheel weights plus a stack of square weights on the back to counter-balance the bucket loader so I need more than an extra pair of hands to lift up the back. :wink:

I'll jack it up and find out what I can see in there. Thanks again for the ideas.

D

I have a follow-up on this issue that may help to shed some light on the cause of the problem.

To recap - this is a 1975 Sears ST/16 that is in excellent mechanical shape other than this problem. The tractor will always go into high range and everything works fine in all 3 forward gears and reverse. It progressively got harder and harder to get into low range to the point where it's really not possible to use any more.

I looked at the linkage as suggested by Dude11 and I think this could possibly be the issue since the linkage from the shift knob where it connects to the shaft running into the transaxel looks like it's very close to the case when it's in low range and may even be hitting but I haven't been able to tell for sure yet.

After fooling around with it while I was examining the linkage, I was able to get it into Low Range again and everything worked perfectly with no gear noise or other problem - for about 5 minutes. When I shifted into reverse to back up then back into first, it was gone again and I was not able to get it back into low after trying at least 20+ times. Later that day I was finally able to get it back into low-range one more time but within a couple of minutes it was lost again after a shift.

The trick to getting it into low gear seems to be shifting the hi/low lever down with sharp pop. Sometimes this will succeed the first try but other times I can do this 20 times in a row with no success so I guess it's really just a matter of rolling the dice. :wink:

If anyone has seen this behavior before I would really appreciate any clues about how you fixed it or even just suggestions for things I could try to fix it.

Thanks,

- D