2007 sportsman 800 efi 4x4 question

[allenmp]

About 3 weeks ago I traded a mc for a 2007 polaris sportsman 800 efi 4x4.

When I test drove it all worked well.

we went to some trails and my son got stuck in some mud and when I pulled him out the 4wd worked great

So a friend of mine wanted me to bring it over to see if it would pull a grader blade he had made.

we were pulling it great till it hit some real loose gravel once he started to spin I told him to engage 4wd.

he engaged it and nothing from the front wheels just rear wheels spinning.

Here is my confusions

I hear JD parts will fit some polaris 4 wheelers cant confirm for the 07

I changed the oil in front differential and flushed out and filled again still nothing

the front drive shaft is turning but front wheels arent (all 4 wheels jacked up)

Checked plugin going to front differential it has voltage.

no noise or anything when in 4wd last but could the cage be bad seems like a popular breaking point

is there other yrs that innerchange with the 07 as far as differential parts

did they upgrade this in the 07

the dealer told be there was 4 different differentials in 07 pending on what month it was built

he also told me it should hole 10oz of fluid but it dont.

I have download the service manual and will print it today but any advice suggestions would be great

thanks Mike