666 shifter hard to move. Need both hands

[LeakyBoot]

Looked at a 666 for sale. Would go into all gears ok but the shifter was so stiff you needed both hands on it. Don't know how these work or what it needs to be free moving???

 

[Janicholson]

Was it very cold, and did the shifter move like it was in tar, or was it mechanically sticky/jerky? if tar like, and cold, it could be wrong transmission fluid. Jim

 

[used red MN]

The shifter on that tractor and the 656 and not sure what other models used that design but it was not the greatest idea IH had came up with. The linked diagram of the shifter linkage shows you how it is fairly complex. If it sat outside a while the horizontal rod of shaft #21 under the dash may have gotten rusted and stiff. Also the 3 levers 32-34 have to pivot freely as well. I would guess that if all that was lubed and freed up it would probably shift okay.
CNHI 666 shift linkage diagram

 

[Mark EC.IN]

Did the lever move hard in the natural slot or was it just hard to get in and out of gear?

If the latter, the TA might need adjusting.

 

[used red MN]

Did the lever move hard in the natural slot or was it just hard to get in and out of gear?

If the latter, the TA might need adjusting.

Just to clarify what Mark is saying, if for example you drive up a slight incline and stop with the TA ahead, and push the clutch. If the TA is not adjusted right the weight of the tractor rolling back against the gears will in that case make it difficult for the gearshift to be pull back to neutral. If everything is working correctly pulling the TA back to the Lo side should release that pressure and let it shift normally if the linkage is free as it should be. There should be minimal added shifting resistance from an incorrectly adjusted TA if the tractor is on level terrain.

 

[BarnyardEngineering]

Yup, two possibilities: Lack of use/lubrication so it's either gummed up or rusted up. TA out of adjustment and transmission is binding.

If the tractor's been sitting outside and not being used regularly, the shifter can get gummed up with old dried up grease. Pop the end cap off the shifter pivot, hose it down with your favorite penetrating spray to dissolve the old grease, and GENTLY work it through its range of motion, adding spray as necessary.

Others have the TA adjustment side covered. If it's just hard to pop out of gear and moves side-to-side easily, that's the problem.

Whatever you do, remember FINESSE over FORCE. Force breaks things.

 

[Mrfred54]

Like all said above, 666,686 should have grease zerks for the horizontal shaft. Left side under the shift handle casting, and right side above the battery on bottom side of steering column. 656 didn't have the zerks and that was supposed to be the improvement to keep the linkage lined but most guys never greased them