HST appears to be slowing down

[Fishguy]

It's been a while since I was on here so hello all! I think I'm having an issue with my NH TC30 HST. Last winter I had abut 350 hours on the tractor and changed all the fluids. But it seems that every since then that the overall speed of the tractor has been going down.

Is there some common problem here? Something easy that I can check?

Thanks in advance,

Steve

 

[dex3361]

It's been a while since I was on here so hello all! I think I'm having an issue with my NH TC30 HST. Last winter I had abut 350 hours on the tractor and changed all the fluids. But it seems that every since then that the overall speed of the tractor has been going down.

Is there some common problem here? Something easy that I can check?

Thanks in advance,

Steve

Did you use the recommended oil and filters or possibly opt for a different brand?
I always check the brakes if the HST is not feeling right. I have left the brake on in low range and it just doesn't feel right so I would check to see if the brakes are dragging or sticking.

Check the fluid level and if you are starving the HST on the suction side it can be destructive. I may consider changing the filters again to see if that makes a change.

 

[Jbrink64]

Check for any looseness in the linkage, also check for pedal binding or any causes that keeps the pedal from traveling to its stops.

 

[Fishguy]

I used NH fluid and filters. Levels are good and I'm getting full travel in the pedal. This area is as flat as it can be and I really could tell you if I have ever used the brakes. There is truely no reason to.
The only that didn't seems right was back when I was changing the fluid. The book says it should take 8+ gallons of fluid to fill it back up. I was only able to get between 6 and 7 gallons in it. Still though, after using it all summer the fluid level is full.

I'm lost,
Steve

 

[Ford tractor]

Did you use the correct fluid? Many new machines need multiviscosity which is typically 5w30 equivalent. But most bucket fluids in the box stores are single viscosity.

Also, (sorry have to ask) did you change the filter for the HST system?

Have you set the machine up and seen if there is a wheel dragging?

 

[jinman]

Fishguy, do you have your Op Manual? If so, it should have specs in the back with transmission speeds for the different ranges. It will state the type of tire (usually Ag) and the engine rpm. The easiest way to check is with a handheld GPS. Anything else is just speculation and individual interpretation; very subjective.

 

[J_J]

I used NH fluid and filters. Levels are good and I'm getting full travel in the pedal. This area is as flat as it can be and I really could tell you if I have ever used the brakes. There is truely no reason to.
The only that didn't seems right was back when I was changing the fluid. The book says it should take 8+ gallons of fluid to fill it back up. I was only able to get between 6 and 7 gallons in it. Still though, after using it all summer the fluid level is full.

I'm lost,
Steve

Common mistake is that you probable will never drain all the fluid out unless you do some extra things. Even when the dripping stops, there is still fluid somewhere.

It probably will not take 8 gal to refill, because if the total fill is 8 gal, and if you drained the sump, there is still fluid in the hoses and cylinders. Probably enough to make the difference of the 6 or 7 gal to refill and the 8 gal total. You could probably use air to force some more fluid out, but leaving it in is of little significance, unless there are particles of trash/debris in the system.

Hydro could be getting weak and bypassing some fluid, therefore decreasing your speed. A pressure and flow test perhaps might give you a heads up on the efficiency of the hydro system. The workshop manual will tell what the flow and pressure should be.