That and not being greased was the most common problem on these. When you take the drive shafts out from the rear diff,loosen BOTH small bolts at the same time or the insert will spin.Items#9,10. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse

 

I've got a bit of trouble here. I've took the rubber cover off the cv joint to find that its full of lithium grease and is working fine. what else could it be? or am i just dismissing this?

 

If you have a 99 model you don't have a cv joint on the rear shafts,just the boot covering the sliding shaft.The 2000 model Diesel had cv joints.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse

 

I've ben looking at the documents and it says its a 2001 model, but i didn't know that they made one then. sorry for not being clear, i didn't really know. yes, i think its CV joints. sorry. what could be the problem with the differential? is there a differential on my quad?

 

Diesel was made from 99-2001. Look on the lower left frame behind the front arm for the vin#. It will show either A99,A00,A10 indicating which year model you have and go from there.Flywheel cover if still has the engine serial # will show what year model also. First two digits in the serial # are the year model..

 

I've just checked the VIN no. and it ends in 10 so its a 2001 model. sorry about that. what would be the problem with my differential?

 

Again may be the cv joints if there is a lot of back and forth play. Rare for this model to lock up as the transmission is pretty tough,but anythings possible.Several good videos on cv joints with differences being how their held to the cv shaft. Either by circlip or by snap ring on later models than yours. Also just replacing one cv joint only to have to replace the other one later ends up costing more than by replacing the whole drive shaft assembly Sixity drive shafts for your model as one example and ebay has a good source for driveshafts.Niche Industries 1657 Tuff Axle Rear Drive Shaft Polaris Sportsman Worker | eBay

 

Well, is there actually a differential in the gear box? So one wheel spins less than the other when going round a corner, because when I took the cv joints out it just seamed to be a fixed insert for both wheels. The quad drives fine it just skids and slides on the chiped drive

 

The "rear diff" and gear case are all the same unit. One internal splined chain driven gear pulls both drive shafts at the same time. If you feel any sliding jerking on one side you can either blame it on the cv joint at the wheel side or the plunging joint at the gear case side.. Look at this parts break down again on internal gear case parts. Item #45 is the splined gear that both drive shafts slip into.Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse Cv joints wear out over time,inner cages can break,spit out bearings even if the boots are intact and full of grease. Just track down which side and which joint.. Again may be cheaper just to replace the whole drive shaft versus one joint at a time.

 

The purpose of a diff is to allow one wheel to slow down when the other wheel does all the work? But the Polaris diff isn't like this, is it? Both wheels spin at the same time