JD 4520 Losing power in C range

rjm5133 · Nov 23, 2010

i have a jd 4520 with 600 hours on it. runs strong in A and B range but has no power in C. it used to go down the road at 15 or 16 mph now runs at 10 tops and slows to 4 or 5 mph on the slightest incline. engine never blogs down more than a hundred rpms and like i said runs fine in A and B and has plenty power in the loader and 3pt hitch

any one else have this problem or have any idea what the issue could be.

any help is much appreciated

RogerH · Nov 23, 2010

Turn off the Load Match feature (your operator manual should describe how to do that) and see if performance improves. If it does, then I would suspect the throttle sensor may be out of adjustment.

KB9UDE · Nov 24, 2010

Possible plugged fuel filter

Cidertom · Nov 26, 2010

Had similar issue on my 4520. My issue was the pressure that drives the hydraulic clutches. (power rev) Dealer shop adjusted it and all better now. It would slip in c or if I was digging into a pile with the fel.

Attached is a drawing of the clutch circuit.

DanD78 · Nov 26, 2010

Is it stuck in 4wd? I would also check the load match setting like suggested before. My 3320 would keep the RPMs up and the tractor would slow down. It keeps you from lugging the engine. I added the cruse control option so you didn't have to go through button pushing to turn the load match on and off.

Dan