Lots of extra drag when 790 4WD engaged

Muxster · Apr 23, 2008

kennyd said:
I disagree, even with the clutch disengaged, the front and rear wheels are still tied together if it's in 4WD, and since the ratio's are different you can can this dragging feeling if on a hard surface.

True... I must have misinterpreted the problem. I thought 1948 meant that the engine seemed more loaded when in 4WD with clutch in. I guess he meant the tractor not engine and then I agree with everyone else that that is normal. ... sorry for the wrong analysis.

1948B · Apr 23, 2008

Yes, I feel the drag when I am cruising along say 5 mph in MFWD and depress the clutch pedal. I come to a stop as quickly as if I had applied the brakes (no matter what the surface -- I first noticed it in the snow). In 2WD, I coast a relatively long ways before stopping.

My father has a 790 just like mine, and says that his coasts in MFWD pretty closely to how it does in 2WD. Mine used to behave like that as well, which is what concerns me.

There are no noises when this happens, but the drag just seemed excessive, and I definitely will use the MFWD even less now. But you cannot get around it for plowing snow, front loader work or mowing around the pond.

Thanks for all the input -- I welcome any more that you might have!

kennyd · Apr 24, 2008

1948B said:
Yes, I feel the drag when I am cruising along say 5 mph in MFWD and depress the clutch pedal. I come to a stop as quickly as if I had applied the brakes (no matter what the surface -- I first noticed it in the snow). In 2WD, I coast a relatively long ways before stopping.

My father has a 790 just like mine, and says that his coasts in MFWD pretty closely to how it does in 2WD. Mine used to behave like that as well, which is what concerns me.

There are no noises when this happens, but the drag just seemed excessive, and I definitely will use the MFWD even less now. But you cannot get around it for plowing snow, front loader work or mowing around the pond.

Thanks for all the input -- I welcome any more that you might have!

My only thought, since you said that it's worse now is to check tires carefully. You haven't changed them have you?

bjcsc · Apr 24, 2008

1948B said:
There are no noises when this happens, but the drag just seemed excessive, and I definitely will use the MFWD even less now.

If it seems excessive you should ask the dealer about it. I think babying it is the worst thing you can do. It's under warranty, right? Push it hard. Any "bugs" that may exist need to be discovered and resolved while you're still under warranty...

JerryG · Apr 24, 2008

As someone said above, has the tires been changed? If the front to rear ratio between the tires don't match up right, it will cause problems. If they have been changed that could very well be your problem.

zzvyb6 · Apr 25, 2008

Check the tire pressures. Run an experiment to see if there is a front pressure other than recommended that makes it better or worse. If so keep it going until you get the lowest drag situation. Do it on a concrete surface: Tires will leave scrub marks if its really bad. Chances are good you have the wrong front of rear tires in the mix. This includes wear state. If you load the rear tires, the extra weight changes the loaded radius and that will also strain the combination, causing drag. Most tractors don't have a viscous front to rear differential, so the driveline is locked together. If there is an rpm mismatch, one axle will complain.

1948B · Apr 25, 2008

My tires are stock. I will check the tire pressures, but it is hard to believe I would get that much drag if the pressure was 2 psi. Unfortunately, my 2004 790 is well out of its 2 year warranty. I was hoping that someone would have a solution that would avoid me having to spend the big bucks at the dealer. I really appreciate all the thoughtful responses.