TX 68+ Hydrostatic drive problem

[WOODCHIP]

Hi all, I have a 2001 New Holland TX 68+ combine, my hydrostatic drive is constantly surging ,it will go slow then suddenly speed up slow , speed up etc . Dealer suggested I change the circuit board in the arm rest which I have done. But no improvement. The belts are good and tensioned correctly, the electric plug to it is clean and not corroded.
I would really appreciate some advice as it's hard keeping a steady flow of crop when it's costanly changing speed. Also she will only now do 12 mph on the road in top gear?

 

[fergie35]

Hi all, I have a 2001 New Holland TX 68+ combine, my hydrostatic drive is constantly surging ,it will go slow then suddenly speed up slow , speed up etc . Dealer suggested I change the circuit board in the arm rest which I have done. But no improvement. The belts are good and tensioned correctly, the electric plug to it is clean and not corroded.
I would really appreciate some advice as it's hard keeping a steady flow of crop when it's costanly changing speed. Also she will only now do 12 mph on the road in top gear?

Axle speed sensor?

 

[WOODCHIP]

Axle speed sensor?

Hi Fergie35 I have taken that out and cleaned it which seems to be reading the speed fine

 

[fergie35]

Hi Fergie35 I have taken that out and cleaned it which seems to be reading the speed fine

The one I used to drive we took it out and left it tied up (as it gives faster road speeds) still tied up now 17 years later!

 

[fergie35]

Could be a failing hydrostat. But you probably didn't want to hear that! Perhaps get the dealer to check the pressures are to spec.

 

[WOODCHIP]

Could be a failing hydrostat. But you probably didn't want to hear that! Perhaps get the dealer to check the pressures are to spec.

Yes this my thinking I was going to call them tomorrow to check oil pressures , I dread to think how much they are to repair

 

[stevedave]

Check potentiometer on the hydrostat lever or the small reed switch that sets neutral on the hydro lever we had the switch move and potentiometer pack up. Speak to David King for parts or mortgage the farm, go to the bank and steel the kids piggy bank money and phone NH dealer to get a price.

 

[MrNoo]

What is it with NH prices?? Have been amazed at some of the ridiculous quotes I've had off them recently. It would almost be cheaper to by a spare combine, just to rob bits off it!

 

[jhorr30]

To be honest it sounds like the hydro pump and motor...
Best be sitting down when you get the price of them. Also need to flush out all the hydro lines to get any bits of metal filings or trash out before fitting new units. Probably won't see much change out of £15k to do the job if you can get the pump and motor. Speak to Stan Briggs about sourcing parts as well as your NH dealer and APH.
Have unfortunately been in the same situation with a tx68 back in 2010.......

 

[stevedave]

What is it with NH prices?? Have been amazed at some of the ridiculous quotes I've had off them recently. It would almost be cheaper to by a spare combine, just to rob bits off it!

I know NH are cruel with parts prices though no doubt someone will be on defending them soon.

 

[snarling bee]

I had a similar problem with my TF78, but nowhere near as severe. Never did resolve it, but it wasn't a big issue.
I would be surprized if it was a oil/mechanical problem, sounds electrical to me. BUT if it is mechanical, I went to Micron Hydraulics in Bradford to get hydro motor and pump rebuilt on my old CR. (Lesson - don't go downhill in too high a gear) They are far cheaper than CNH, and did the job in one day while I waited (what to do in Bradford for 7 hours??). It might pay to give them a ring to see if they have any ideas as to the cause of your problem.

 

[MrNoo]

I know NH are cruel with parts prices though no doubt someone will be on defending them soon.

Header auger drive sprocket (with no slip clutch) £800-1200 depending on which one it is, I could get one made up for a 1/3rd of that. Grain flow sensor, £2,400 or £1,500…..!!! I found them very reasonable in the past but they are just leg lifting now.

 

[snarling bee]

pressure sensor - local factor £19 delivered, NH dealer £52 + collection or p&p.

 

[Mr Happy]

I had a similar problem with my TF78, but nowhere near as severe. Never did resolve it, but it wasn't a big issue.
I would be surprized if it was a oil/mechanical problem, sounds electrical to me. BUT if it is mechanical, I went to Micron Hydraulics in Bradford to get hydro motor and pump rebuilt on my old CR. (Lesson - don't go downhill in too high a gear) They are far cheaper than CNH, and did the job in one day while I waited (what to do in Bradford for 7 hours??). It might pay to give them a ring to see if they have any ideas as to the cause of your problem.

Mark Cheshire is the man to contact at Micron a very clever guy and knows his stuff when it comes to piston pumps and motors.

 

[Gedd]

Hi all, I have a 2001 New Holland TX 68+ combine, my hydrostatic drive is constantly surging ,it will go slow then suddenly speed up slow , speed up etc . Dealer suggested I change the circuit board in the arm rest which I have done. But no improvement. The belts are good and tensioned correctly, the electric plug to it is clean and not corroded.
I would really appreciate some advice as it's hard keeping a steady flow of crop when it's costanly changing speed. Also she will only now do 12 mph on the road in top gear?

 

[Gedd]

Had a similar problem on a class dominator last year now I'm no fitter but seem to remember that there's a spring with a ball bearing that alters forward reverse that had come to pieces new spring problem resolved

 

[WOODCHIP]

Thanks guys for all of your input, fitted a new speed sensor this morning , combing rape nearly all day it only played up once for about a minute ? And was fine all day , I will see how she goes tomorrow.
I think its more electrical because when it does play up their is like a sizzling sound in the arm rest .

 

[Vernon]

Thanks guys for all of your input, fitted a new speed sensor this morning , combing rape nearly all day it only played up once for about a minute ? And was fine all day , I will see how she goes tomorrow.
I think its more electrical because when it does play up their is like a sizzling sound in the arm rest .

Sounds exactly like mine with the buzzing in the arm rest. Can go fine for days then drive you mad for an hour speeding up/slowing down 0.5k at a time, then be fine again. Mine was hugely improved by wedging a piece of cardboard in beside the potentiometer. Also a 2001 model.
Vernon

 

[JJT]

Had to put a new potentiometer in my tx65 coupleof years ago. David king did.it for not a lot of money. But you may have already changed that if you put a new circuit board in the arm rest.

 

[D14]

Sounds typical of a failing hydro. Just to be sure get it pressure tested if I was you. Getting it early would save big costs.