What is this extra hose for on my 990?

[robpm]

Jwinner, it is interesting, I went to the parts section of the JD web site for the 4005 located here John Deere - Parts Catalog and I could not find this rear auxiliary hydraulic kit like what is listed under the 990 which is under the hydraulics section for the 990. I was wanting to see what was different but there is no way to tell looking for the part this way.

 

[Bob1070]

I own a JD1070 with the same add-on rear hydraulics as shown in your photos. I do not have the return flow from my backhoe flowing into the right side of my transmission case as your photos show. The return line of my backhoe attaches to the one foot long hose you are questioning.