Repairs Craftsman LT1000 20HP 42" Transmission Jumping In And Out Of Gear

Hello All,

Model #: 917.272920

I have replaced the drive belt for starters. The engine starts and runs fine. The transmission will not engage until I have the drive hand lever (aka the foot pedal on the newer models) almost 2/3 of the way to the max and then jumps into gear, usually popping a small wheelie as a result and then whines lightly when it first jumps. If the mower starts descending down a hill and rolls slightly faster than the transmission is running, the transmission will disengage and I will have to push the hand lever even closer to the max and it will jump back into gear once more. Reverse is iffy. If the mower is slightly rolling backwards, reverse usually never kicks in.

If anyone needs more info, just let me know.

Any ideas are greatly appreciated!

Padoke said:

Hello All,

Model #: 917.272920

I have replaced the drive belt for starters. The engine starts and runs fine. The transmission will not engage until I have the drive hand lever (aka the foot pedal on the newer models) almost 2/3 of the way to the max and then jumps into gear, usually popping a small wheelie as a result and then whines lightly when it first jumps. If the mower starts descending down a hill and rolls slightly faster than the transmission is running, the transmission will disengage and I will have to push the hand lever even closer to the max and it will jump back into gear once more. Reverse is iffy. If the mower is slightly rolling backwards, reverse usually never kicks in.

If anyone needs more info, just let me know.

Any ideas are greatly appreciated!

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Are you saying it was doing the same thing before you changed the drive belt.

shiftsuper175607 said:

Are you saying it was doing the same thing before you changed the drive belt.

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Yes, sorry I wasn't very clear on that. Yes the mower transmission had the exact same symptoms before changing the drive belt. I just assumed changing the drive belt would be an easy first step.

Padoke said:

Yes, sorry I wasn't very clear on that. Yes the mower transmission had the exact same symptoms before changing the drive belt. I just assumed changing the drive belt would be an easy first step.

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Have you had this a while? Or, is it new to you?

It has 5 or 6 speeds?

Push clutch pedal in all the way
Put in a lower speed...such as number 1
ease out clutch pedal and mower should mow slowly forward.
While moving you can...repeat process and shift to a higher number to go a little faster.

I'm not actually sure how many gears the mower has because it has a hydrostatic transmission and a slide lever to speed it up or slow it down. The further you slide it forward, the faster it goes. I paid $100 for the mower and it's had this transmission slip issue since I've had it.
The mower will not move as I slowly push the lever forward with the clutch released. It will finally grab violently and take off.

Padoke said:

I'm not actually sure how many gears the mower has because it has a hydrostatic transmission and a slide lever to speed it up or slow it down. The further you slide it forward, the faster it goes. I paid $100 for the mower and it's had this transmission slip issue since I've had it.
The mower will not move as I slowly push the lever forward with the clutch released. It will finally grab violently and take off.

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The manual explains on page 13 how to control speed/drive

https://www.manualslib.com/manual/496477/Craftsman-917-271920.html?page=13#manual

You are correct, and the instructions are being followed. The clutch is disengaged, the throttle is in the correct position. As Step 3 in the "To Move Forward and Backward" states, I slowly move the motion control lever forward but nothing happens until it reaches 2/3 of the way to the max and it jumps into gear with a jolt and move forwards.

I just think the mower should respond with a slower, smoother response much sooner when I push the motion control lever forward before it's passed the halfway mark.

Padoke said:

You are correct, and the instructions are being followed. The clutch is disengaged, the throttle is in the correct position. As Step 3 in the "To Move Forward and Backward" states, I slowly move the motion control lever forward but nothing happens until it reaches 2/3 of the way to the max and it jumps into gear with a jolt and move forwards.

I just think the mower should respond with a slower, smoother response much sooner when I push the motion control lever forward before it's passed the halfway mark.

Click to expand...

figure out what the "motion control lever" does as it slides forward...moves a cable? a rod?
See if it is binding, sticking, can be adjusted.

Could it need to be purged? Sometimes air can get trapped in the unit.

This could be possibly a 2-part fix. I was able to get the mower up on 4 jack stands once the deck was removed. I put a 20 lb. weight on the seat and started it up. I laid down on my side to look underneath it, I wasn't brave enough to actually lay completely underneath it. I started using the speed control lever and observed the linkage and at what time the wheels would actually engage. There appeared to be a bolt that was loose causing the control arm to not push down on the linkage assembly fully until the arm was sitting almost at the highest speed. The only reason I could see that it was actually allowing the wheels to engage at all was due to the shape of the arm assembly connected below the speed control lever. I put about 1 - 1.5 turns on that bolt and noticed the linkage was reacting faster was I pushed the lever and the wheels were kicking in faster.

I also followed the instructions to purge the transmission as recommended.

The result, the mower is now smoothly moving forward and backwards with no lunging or delays.

Thanks, fellas!