Why do the 4X20 series tractors have three top link holes?

[dusty3030]

I've read the manual. I understand one is for light, one for medium, one for heavy. But is there any harm in leaving it in heavy hole all the time?

 

[beenthere]

No harm.
Just the angle at which the plane of the 3 pin connection pts changes differently as the arms are raised and lowered. Three degrees of freedom or selection.

i.e if you have a working platform or carry-all, then one setting will keep the carry-all level whereas another selection of holes may not.

 

[RoyJackson]

The older 4xxx (1998-2005) series tractors also have three upper link holes. I leave mine in the "heavy load" hole for everything.
The only disadvantage I see is in using one hole continuously is it may result in egging the hole. This is a casting, BTW, so take a look at it now and then (once or twice a year). That said, my 4400 is almost 12 years old with 870 hours and still looks good to me.
I've only heard of one of these castings break, BTW.

 

[joe48]

just curious how does JD list these holes (top to bottom) for the light medium heavy rating?

 

[RoyJackson]

just curious how does JD list these holes (top to bottom) for the light medium heavy rating?

From the manual:
Positioning Center Link

MX4743

For light and medium draft loads: Install center link (A) in bottom hole (B) of mounting bracket. Example of light and medium draft load implements would include a landscape rake.​

For medium and heavy draft loads: Install center link in middle hole (C) of mounting bracket. Example of medium and heavy draft load implements would include a tiller or box blade.​

For very heavy draft loads: Install center link in top hole (D) of mounting bracket. Example of very heavy draft load implements would include a plow or ripper.

I'd suggest most of us could use the center or top hole excclusively​

 

[joe48]

thanks Roy that was great to show the pic from manual.

Most of the time I use the bottom "light" hole with my bushhog and snowblower, to get more "lift" clearance.
When on rake or boxblade I use the top to get better control over lift arms, I use middle or top for tiller.