TN65s won,t move forward or reverse

[mahlers]

Hopefully that's not the problem, but if it is, at least you'll get it fixed. I think the tractor has to be split in order to get in there (might be wrong about that). One of the things I've been looking at on my tractor is the dump valve. I've tried to read as much as I can about how this PowerShuttle transmission works, and from what I've been able to figure out (which isn't much - these things are complicated) is that the dump valve can get stuck in a position where it keeps the tractor from moving. On mine, I ruled that one out since I can still move the tractor in reverse - so I know the dump valve is still working. But, there are a few failure modes where the ECM will activate the dump valve as a safety measure to keep the tractor from moving (clutch solenoids shorted, for example) and I believe the dump valve can get stuck in the "dump" position. Not sure if that helps as your tech probably looked at that - but my gut tells me it's more likely for a solenoid, valve, or wiring to go out than the transmission coupler. I'd think the transmission coupler is built stronger than a brick $hithouse...

 

[RickB]

I talked with the mechanic that looked at the tractor on Friday.

He thinks that the transmission coupler may have stripped out.

I still wonder why the A and B clutch hydraulics wont pressure up? He figures that the clutch packs are not spinning so the ECM won't activate the solenoids and won't allow calibration.

My manuals do not cover what this coupler looks like. I will call them for a parts break down.

Ryan

I can't offer anything productive to the mix, but I think your local technician is in the weeds. The only shaft speed sensors are on the rear pinion shaft or the 4WD clutch input and output shafts, depending on equipment. None of which will detect shaft rotation during or before calibration. In fact, if rotation is detected, calibration is aborted. The calibration cycles are completed when the clutch being calibrated locks up to the point that ERPM's drop a specified amount.

 

[DRB at SAGC]

I can't offer anything productive to the mix, but I think your local technician is in the weeds. The only shaft speed sensors are on the rear pinion shaft or the 4WD clutch input and output shafts, depending on equipment. None of which will detect shaft rotation during or before calibration. In fact, if rotation is detected, calibration is aborted. The calibration cycles are completed when the clutch being calibrated locks up to the point that ERPM's drop a specified amount.

He figures that the clutches are not spinning because the input shaft is not turning there for the clutches will not calibrate?

I have a hard time with this theory as you would think that the clutch pack should still hydraulically pressure up. They may not calibrate because the engine RPM would not drop. I have no hydraulic pressure at the shuttle valve test ports past the A and B solenoids.

Is there any way to activate the A or B solenoids manually? I see on one of the wiring diagrams that I have it shows a Limp Home Strategy that plugs into connector B (red). I will see what the dealer says about this tool.

Splitting this tractor to find out it is not the coupler sure would be a lot of work for nothing.

I need to do more research first.

Ryan

 

[mahlers]

Just out of curiosity, did you and/or the tech have a look at the dump valve? It's a longshot, but if it's stuck in the "dump" position, I'd think that you wouldn't be getting any pressure to the solenoids.

I'd also be interested in learning more about the "limp home" procedure. From what I can see, if the solenoid gets 12v applied to it, it will activate.

 

[mahlers]

Just out of curiosity, did you and/or the tech have a look at the dump valve? It's a longshot, but if it's stuck in the "dump" position, I'd think that you wouldn't be getting any pressure to the solenoids.

I'd also be interested in learning more about the "limp home" procedure. From what I can see, if the solenoid gets 12v applied to it, it will activate.

 

[DRB at SAGC]

Just out of curiosity, did you and/or the tech have a look at the dump valve? It's a longshot, but if it's stuck in the "dump" position, I'd think that you wouldn't be getting any pressure to the solenoids.

I'd also be interested in learning more about the "limp home" procedure. From what I can see, if the solenoid gets 12v applied to it, it will activate.

The way I figure that the dump valve works is that when electrical power is applied to dump solenoid it it allows hydraulic oil pressure to flow to the A and B solenoids. At least this is how I see it from the pressure testing that I have done. I would like to see a hydraulic flow chart from New Holland to confirm this it is not in the manuals that I have.

I will ask about the limp home when I call.

Ryan

 

[RickB]

Just out of curiosity, did you and/or the tech have a look at the dump valve? It's a longshot, but if it's stuck in the "dump" position, I'd think that you wouldn't be getting any pressure to the solenoids.

I'd also be interested in learning more about the "limp home" procedure. From what I can see, if the solenoid gets 12v applied to it, it will activate.

The dump valve question has legs.
The F & R solenoid coils are PWM coils; you go feeding them 12V and you will fry them.

 

[DRB at SAGC]

My New Holland dealer says that the Limp Home tool is available its about $80 the only thing is it's about 3 weeks away.

Yesterday I did some by pass electrical testing to determine if I could get hydraulic pressure to the A clutch pack.

All test were done with tractor jacked off the ground and 4wd turned off.

First I unplugged the dump solenoid. This allows oil pressure to the A & B solenoids. Pressure gauge confirmed that I have about 220 psi after the dump valve.

I disconnected the A coil from the wiring harness and wired up a power feed from the battery with an on/off switch. When the A coil was energized a pressure gauge confirmed that I had about 220 psi on the clutch pack side of A solenoid. This is the first time that I have had a psi reading on this side.

With the clutch pack engaged the wheels would not spin, I could shift gears with no grinding both the main gear and the range gear. This is leading me to thinking that the main coupler to the engine is broken. Can the ECM sense if the main input shaft is turning?

BTW I think that the PWM ( pulse width modulating ) coils are rated at 12 volts so feeding 12 volts though them should be ok. I think??? The ECM use the pulse width the regulate how hard the solenoid valve engages the clutch packs.

Ryan

Ryan

 

[mahlers]

It's interesting that you got pressure after disabling the dump solenoid and then energized the A solenoid. Hopefully some of the techs chime in because I'm really curious to hear where this goes. These transmissions are really complex - in the last week of messing with mine, I've managed to put it into a few fault modes that completely disabled the transmission and I ended up chasing my tail for hours trying to figure it out. Then, I'd just put everything back together, shut all the electricals off, reset it all, and I'd be back to square one again (same error code 41).

Unfortunately, in my case, one thing that messed me up was I'm 99% sure that I got a bad diagnostic tool... I spent hours trying to figure out why it wouldn't reset codes or allow me to scroll through channels - and I figured it was the bad ECM that was keeping the diagnostic tool from working. For the heck of it, I hooked it up to a friend's tractor, and it didn't work on that one, either, so the diagnostic tool is headed back for replacement...

When you changed out your filters, you didn't notice any metal or anything unusual, did you? If you broke the input shaft to the transmission, I'd think that you'd see some stuff in there. It might have broken completely cleanly, so that may be irrelevant. When the tractor stopped working, did it just 'stop' and then show error codes, or did the operator notice something go "bang"? If the shaft to the transmission broke, I'd think that the operator would have noticed it... Those things don't break in the same elegant way the electronics break

 

[DRB at SAGC]

malher just a thought about the controller are you holding the H MENU button down before you turn the key and waiting until HH MENU appears on the screen? Then you can scroll through the H functions with the H MENU button. I got this wrong when I first used my diagnostic tool.

They figure that the coupler at the engine broke outside the transmission. I am still not sure what this thing looks like.

The operator was driving the tractor up a grassy hill with a load on the forks and the tractor just stopped climbing and started rolling back and it has not moved since.

Ryan