TN75SA power shuttle problem?

[ironpen]

Bump back into activity.

 

[mytreefarm]

A quick update to my last post.
Downloaded the Service Manual and started going thru the tractor wiring.
All the wires, switches, sensors I could get at without taking things apart looked good. I concluded the ECM was bad.
Trailered the tractor to NH dealer. Only took a few minutes to confirm the ECM was bad. Installed a new one, checked remaining circuits via the diagnostic tool and calibrated as needed.
The new ECM flashed us an '82' error code.
Short Circuit in Transmission Pressure Sensor.
Didn't take long to installed a new one-after removing left rear tire.
Now working ok.

 

[RickB]

I have a 2002 or 03 TN75S and I have developed a similar problem. The only way it will move is to put it in gear and engage the power shuttle with the clutch depressed and then release the clutch. If I put it in gear and move the power shuttle to engage, the yellow light blinks on the dash and nothing happens. If I push the clutch in and let it back out, everything then engages and I move away normally. The beeper that indicates the parking brake is not on that makes that god awful racket (until you put the parking brake on when you shut the tractor off) makes the same racket when I put it in gear as I am taking off and then stops after about 12 beeps. For a while that same beeper would just come on periodically while using the tractor, but the dealer replaced the switch under the seat and that stopped.....except when I put in gear and first drive away. I guess I should be happy I figured out what to do to make things operate normally except the power shuttle should not require that I depress the clutch all the way, put the power shuttle lever in forward or reverse and THEN let the clutch out to make it engage. It will go from forward to reverse without depressing the clutch just like it's supposed to. My dealer has tried but has no answers at this time. Anybody with a similar episode. Not exactly like described above, but it smells similar to me. I have about 1200 hours on the tractor. Very pleased with it overall, but I would like to resolve this if I can so I won't get stranded someday. Thanks.

You are likely to have a problem with the sat switch or its wiring circuit. The ECU simply isn't recognising your butt is in the seat.

 

[mojoinco]

Sounds like a new gummint requirement: butt print id check.

 

[jusalooking]

I Have a TN75SA a 2006 4x4 with a 32la Loader, I was dumping a bucket of Insilage for our Feeder Cattle in the Bunks when it just Quit, It turned out that a plug had feel off the ing switch, After replaceing it wouldn,t move noway shape or form, We hauled it 50 miles to the closest NH Dealer that knew anything about them, Turns out the wires rotted off the back of the fuse Block, What the H is up with that, The wires are tiny, Every connection is full of Blue junk, Did this come from the Boat ride from Italy with all of the Sea Salt, A tractor 5 yrs old and the wiring is junk, Hum we were just getting Ready to Buy a New Workmaster 75 horse 4x4 with Cab and loader but is the Same thing going to happen 5 yrs down the Road, Other than this it has done everything that has been Asked of it, But the Rust problem on a 5 yr old tractor with 1100 hrs on it shouldn,t happen

 

[Harry in Ky]

Here's another tidbit. The power shuttles have status switches on the transmission shift rails, one on each rail. These switches are not simple on off switches, they are variable resistance. I think there is a procedure in the manual for checking with an ohm meter and adjusting with shim washers to achieve a certain resistance in each gear or speed range. The controller then monitors the values to determine the selected speed range and decides how quickly to engage clutch packs. Not sure what serial number ranges used which controller and switch combo, but I've seen two tractors with a status switch issue. Controller gets(or doesn't get) a signal it recognizes and thinks you have'nt shifted all levers into gear. Clutch packs won't engage if trans is in neutral, hence no error codes. My dealer rep suggested removing switches one at a time and removing the shim washer to change reading to see what happens. Worked for me.

 

[jusalooking]

You know it is a nice tractor but why in the World do they to mess it up with all the electric stuff, a little all right but they went overbroad with this one, Whats going to happen 10 to 20 yrs down the Road when parts are no longer there

 

[Sam56]

I am having the same problem with my tn65s. Occasionally I will get a 15 error code before it happens.

 

[feliks]

I have a 2002 or 03 TN75S and I have developed a similar problem. The only way it will move is to put it in gear and engage the power shuttle with the clutch depressed and then release the clutch. If I put it in gear and move the power shuttle to engage, the yellow light blinks on the dash and nothing happens. If I push the clutch in and let it back out, everything then engages and I move away normally. The beeper that indicates the parking brake is not on that makes that god awful racket (until you put the parking brake on when you shut the tractor off) makes the same racket when I put it in gear as I am taking off and then stops after about 12 beeps. For a while that same beeper would just come on periodically while using the tractor, but the dealer replaced the switch under the seat and that stopped.....except when I put in gear and first drive away. I guess I should be happy I figured out what to do to make things operate normally except the power shuttle should not require that I depress the clutch all the way, put the power shuttle lever in forward or reverse and THEN let the clutch out to make it engage. It will go from forward to reverse without depressing the clutch just like it's supposed to. My dealer has tried but has no answers at this time. Anybody with a similar episode. Not exactly like described above, but it smells similar to me. I have about 1200 hours on the tractor. Very pleased with it overall, but I would like to resolve this if I can so I won't get stranded someday. Thanks.

Ironpen,
Did you ever resolve this issue? My tn75da started doing it this morning and the beeping is driving me crazy! Like you said, I can't move the tractor unless I press in the clutch and then move the power shuttle lever and then let the clutch out. I dont see any error codes, I only see the tranny light flash when I engage the power shuttle without pressing in the clutch.
Thanks.

 

[RickB]

See post #13 in this thread. Seat switch or seat switch circuit problem.