# New Holland 5635 4x4 not disengaging (I think)



## Azitizz (Jul 30, 2021)

Hi there. New to the forum. I'm a volunteer maintenance fellow at a large meditation centre in Quebec. We have a 5635 NH tractor on site and I am trying to troubleshoot a 4x4 issue. It appears the 4x4 is stuck ON. 

How do I tell for sure though? Ive found the wires going to the solenoid, and Ive disconnected it light goes out on the 4x4 switch in the cab, but how to know if it is really disengaged without propping the whole tracor up and watching if the wheels turn front and back both turn? 

Manual says bad wiring can lead to 4x4 being stuck on. But so far havent found a smoking gun. 

I can see the drive shaft that runs from the transmission to the front gearbox/differential is always turning, switch on or off, but would the shaft be turning normally with 4x4 disengaged? Thanks for any help out there.
Michael


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## Azitizz (Jul 30, 2021)

Azitizz said:


> Hi there. New to the forum. I'm a volunteer maintenance fellow at a large meditation centre in Quebec. We have a 5635 NH tractor on site and I am trying to troubleshoot a 4x4 issue. It appears the 4x4 is stuck ON.
> 
> How do I tell for sure though? Ive found the wires going to the solenoid, and Ive disconnected it light goes out on the 4x4 switch in the cab, but how to know if it is really disengaged without propping the whole tracor up and watching if the wheels turn front and back both turn?
> 
> ...


Sorry I'm moving this post to


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## Azitizz (Jul 30, 2021)

Azitizz said:


> Sorry I'm moving this post to "Repair and technical questions" where it should have gone in the first place...


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## pogobill (Jan 31, 2012)

Azitizz said:


> Sorry I'm moving this post to


No, it belongs right here. If you or anyone else is looking for information on a Ford / New Holland tractor, you don't want to sift through 1500 posts on why a Satoh Bearver has a dead battery or a 9N backfires!


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## Fedup (Feb 25, 2014)

Yours is by no means an uncommon problem. The 4WD function on that model is similar to many of the other models produced and marketed by New Holland. The drive shaft you mentioned will turn whenever the tractor is moving whether the front axle is engaged or not. The 4WD feature is mechanically applied through a spring loaded coupling inside the drop box below the transmission. In order to disengage it hydraulic pressure must be applied to an internal mechanism which compresses the spring and separates the coupling. There will be a solenoid valve somewhere on the outside of said drop box that requires 12 volts to do that. 

If you jack any one tire off the ground with the transmission in neutral and the engine off you should not be able to turn the tire. Start the engine, apply 12 volts to the solenoid and then see if the tire will turn. If it does, then the hydraulic and mechanical portions of the system are probably working and the problem is mainly electrical.


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## Azitizz (Jul 30, 2021)

Life curcumstances kept me from adressing this issue, but the forum here has never left my mind. It was coming time to adress this issue of the 4x4 not disengaging, I was going to try Fedups suggestion for troubleshooting, but recently as an operator was moving sand with a bucket attached, no particular odd loads or odd circumstances, a loud pop or bang was heard. Nothing was visually obvious and he continued to use the tractor for the day without issue, 

But when moving some wood with a loaded bucket on an uneven surface it was obvious only one rear wheel was driving, and it was spinning in sand, so he was stuck until he unloaded and moved around to free the tractor. Driving on the road is fine, but it appears something may have gone awry... I will be checking it today any suggestions on what to check for? (perhaos opening diff to inspect?) 
Thanks
Michael


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## Fedup (Feb 25, 2014)

Opening the differential would be a last resort. Start with determining if the front axle is driving or not,(whether selected or not) then move on from there. 

One rear tire spinning with tractor not moving would indicate no drive from the front. A loud bang and no drive from from one rear wheel could indicate a broken pinion shaft on the side that doesn't drive. That might be worth investigating.


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## Azitizz (Jul 30, 2021)

Thanks. Ill start with your suggestions. Couldnt get to it today. We will see about tomorrow. Will post what I find.


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## Azitizz (Jul 30, 2021)

So it doesnt appear like anything major is broken, (exept for the original problem)

We Jacked the 4 wheels independently then all at once to see whats happeneing. The rear wheels behave normal it appears, However I tried playing with the differtential lock swithc and it didnt make any chages in behavior. I can still hold one wheel steady while the other turnes when both are jacked in the air and turning on a low gear.

The front wheels also lifed at teh same time, acted the same breifly, but then while holding both wheels steady, we can feel whats seems to be after a rotation of the drive shaft or on some regular interval a push to turn but not enough to slip from our grip. I can hold one wheel steady and the other will turn, or both will turn if let go but both can also be held steady but with that slight push every couple of seconds as if it almost engages but then doesnt.

Turning on or off the 4x4 switch does not change anything. Still not sure how the Diff, lock switch should work when all 4 wheels are jacked in the air. Would someone need to be actively holding the switch down with a brake to keep the differential locked?


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## Fedup (Feb 25, 2014)

Azitizz said:


> So it doesnt appear like anything major is broken, (exept for the original problem)
> 
> We Jacked the 4 wheels independently then all at once to see whats happeneing. The rear wheels behave normal it appears, However I tried playing with the differtential lock swithc and it didnt make any chages in behavior. I can still hold one wheel steady while the other turnes when both are jacked in the air and turning on a low gear.
> 
> ...


You have me all confused. Too many irons in this fire. Go back to square one. Jack ONE front wheel, leave the engine off. Can you turn that wheel? If so, something's wrong. If no, then the front wheel drive is connected and engaged. Was that not the original question?


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## Azitizz (Jul 30, 2021)

By the time I got to the shop and tractor I had several theories floating in my mind and I wanted to test them out. I did do the single front wheel. Engine off, in neutral, the wheel turns. Engine running (ignition on) the wheel still turns but it wants to catch on something every rotation, but not agressively. That is for the front wheel.

Same with the single rear wheel. It can turn by hand when jacked. I had it in neutral however which makes me think I should have had in in gear for that test.?

The other tests were to see how things were working. All 4 jacked, all weels turn. For the rear, grab one wheel while turning and it stops but not the opposite side. It keeps tunring no matter what.
For the front, they turn but you can stop both wheels by hand and feel a grabbing but as mentioned before, not agressive and it happens at a regular inteval as if related to internal shaft rotation.

I was pushing a pile of dirt up agains a wall and had both rear wheels spinning digging into the earth, so It seems both rear wheels are turning...

The 4x4 light is always on. It had randomly turned off on rare occasion, but had to say if it was really off.


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## Fedup (Feb 25, 2014)

It seems you're getting different results from each wheel. The easiest thing to check is the drive shaft couplers. That's where I would go next. It's probably the most common failure in that type system and it's also one of the few non lubricated parts. The front one is most likely to go first since the front axle pinion shaft has much more movement than than the rear shaft from the drop box.


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