So..... I have a 2008 Polaris Sportsman 800 EFI, that I am having problems with my 4WD. I pulled the front diff out, opened it up and found the problem,(so I thought). I replaced the plastic carrier cause it was in pieces and I also replaced the Armature plate.
I installed it back into the quad, hooked everything back up,(driveshaft, axles,vent tube, ADC filler tube, wiring and filled fluids) but yet my 4WD/AWD won't kick-in/engage. I used a test light to make sure I had power going to it at the 4 wire plug and at the diff where the wires go into it. When it's switched into 4x4 the test light lit up and when switched to 4x4ADC the test light lit up as well.
I'm stumped why it won't engage, I talked to a couple Polaris dealers around me and they really didn't have much to offer me. Has anyone ever had or heard of this problem before?
Thanks Matt

 

Check that you have around 24 ohms resistance between the gray and brown/white coil wires in the diff. If readings vary a lot either way the coil may be too weak to grab the armature plate.

 

Well, that would be a negative on the 24 ohms. 11.3 is what it says, not sure if I have the meter on the correct settings.

 

Well... Not really close to the 24ohms, only 11.3. I'm not sure if I have the meter set on the correct settings, but the setting that I'm in is the only one that came up with a reading.

 

I tested it again, and the meter read 11.3 ohms.

 

Sounds like that may be the problem if you're sure everything else has been installed correctly,voltage ok,etc to the diff.Manual has a flow chart on this and if ohms are not within range it says to check the diff. If cover plate and coil is the problem,it's an expensive part. Item #1.Polaris ATV Parts 2008 A08MN76AF-AL-AQ-AR-AS-AT-AX SPORTSMAN 800 HO EFI DRIVE TRAIN, FRONT GEARCASE and MOUNTING Diagram

 

I checked the coil for the 4x4ADC and that read 23.6 ohms. I haven't checked the voltage going to it yet, but would I check that while the quad is running or just the key in the on position?

 

Key on position while in gear.Doesn't have to be running.

 

i tried checking to see if I had voltage going to the coil in the diff and I wasn't coming up with any reading on the meter, I'm not sure if I had the meter on the correct settings but I'm going to look at it again tonight when I get home from work.

 

Dc voltage setting. If no voltage is present while key is on,in gear and awd switch on,could be the problem of loosing ground through the speedo that some have had. If this is the case(and the awd light isn't on) you can try jumping the brown white wire to the solid brown in the speedo harness. This bypasses the speedo for the awd ground circuit.