First post! Need help with 2004.5 Sportsman 700

I’ve been a lurker on this for awhile and finally joined. My questions are in regard to a Sportsman 700 I just picked up for 250.00! Its needs work, but i felt that 250.00 was a reasonable price for a project bike.

Its a 2004.5

– Its needs new rear diff bearings and seals. Will an 05 kit work with model or no?

-The previous owner has said that the 4 wheeler will not disengage out of 4×4, even after rebuild. I’ve found that this is a semi common issue. What is the best plan of attack on that?

-what is the major differences between the 2004.5 and 2004/2005?

Any other info yall may have would be great. Thanks