OEM PDF you can print out or reference.
Since no one has posted about doing this, I decided to give it a try on my 850, should be the same for any 550/850/1k bikes. These parts are used in diesel rangers and the highlifter 850/1k

I have had no trans issues to date, but wanted lower gearing.
I’m in the process of installing the parts, not quite done as our set of snap ring pliers just crapped out. Also waiting for a new trans to engine gasket.

Ranger gears and chain part numbers are posted in the pic, also a Turner Cycle reverse chain upgrade was installed.

Special tools-A number torx drivers are used and listed in the pdf 25 and 27 I think, 2 sizes of snap ring pliers are needed as well as a bearing puller for the bearings on the shafts in the trans.

I went the long way and pulled the trans, but now having it apart It could be done quicker in frame.
The pdf instructions are pretty good and I’ll take some more pics before putting it back together.