HOw does the active descent control werk?
I see it needs its own special fluid which is now the same oil as the front gear case (demand drive plus fluid)...but does it activate some brake in there? where does it go if it gets low in the reservoir, etc.
i kinda figured it was an engine brake of some sort until i got a quad with it but apparently not , it seems to be its own system.

and what is the fluid? is there any "generic" substitute? trans fluid, brake fluid, mineral oil...???

 

with most Polaris owners, the 'generic" substitute for the ADC is.....squeeze the brakes and stick out both your feet....LOL... jk, can't resist a chance to take a shot at Polaris....sorry.
it does act like "add on" engine braking, it produces a counter force to the drivetrain's tendency to free wheel down inclines when the throttle is released and the clutch rpms drop below engagement point. On old Polaris quads, you either had to ride the brakes...hard, or keep blipping the throttle to keep the clultches engaged, not the thing you want to be doing when heading down a steep incline.

 

Wouldn't it be a steep decline if you were heading down???
For the OP, I can't explain how it works, but it keeps the front end engaged and the clutches in there provide braking action. By keeping the front end locked in, it keeps the rear from locking up and sliding. (or in Specta's case, it doesn't do anything ) As for the fluid, there is no substitute for the demand drive plus.

 

ADC has nothing to do with engine braking. EBS and ADC are two different systems. When the adc is on it allows the front wheels to be locked in so it also has engine breaking on the front wheels. They have this system because with the demand 4drive system the front tires are only locked when you are spinning so when you let off the gas the ebs is only apllied to the rear wheels. As opposed most jap bikes when they are in 4wd and you let off the gas the engine break works on all 4 wheels.

This was Polaris's way of offering 4 wheel engine breaking.

As far as the mechanical side I am not sure how it works, am interested in that as well.

 

The front gear case has two coils,one is the central coil, armature plate and hilliard assembly and one coil for the ADC. In ADC mode 12 volts is present at the input shaft ADC coil which is controlled by the ECU GROUNDING and UNGROUNDING the coil. The coils magnetic field attracts a splined armature plate on the shaft. The energized plate attracts a unsplined eccentric cam which activates the hydraulic ADC pump. The pump forces fluid through each case half to a piston that the fluid forces inward compressing clutch packs on each drive shaft forming a dynamic coupling to each drive shaft resulting in a true all-wheel EBS upon deceleration. Current to the ADC coil from the ECU is turned off anytime you push the throttle off idle or vehicle speed is above 15 mph,or you switch the AWD mode to 4X4 or 2X4. Hydraulic pressure stops and the pistons release,disengaging the ADC function.This is from the 850 manual,it explains how the system works a hell of a lot better than I can The clutch packs(just like the steel and fiber plates in a motorcycle clutch) are why the fluid in the main gear case gets dirty quicker and needs to be changed frequently,just more parts to deal with that contaminate and break down the fluid. Plus this could be the noise a lot of people are hearing when going down inclines,the clutch plates grabbing ,then unlocking. OPT

 

Thanks for the explanation OPT!

 

How does it work?? It doesn't.

I've had two 2012 Tourings, a 550 and an 850 and it works less then 25% of the time on both machines. The 550's didn't work with less than
10 miles on ot and the 850 started having issues with less than 100 miles on it.

The 550 spent 3 weeks at the local dealer and they couldn't fix it (or the other issues) in fact they said they couldn't find anything wrong with it even after putting 22 miles on it.

Thought it was funny after getting it back it didn't work the very firs time we tried it.

I'm not even going to bother taking the 850 in to have them "fix" it.

 

Don't know your status with the individual dealer,Polaris Industries themselves or Doug Myer,but I had a good relationship with three Polaris engineers that they knew when I called them that I had a problem! I had no problem in getting warranty authorization #'s on many items such as gear cases,especially when they came out with the centralized awd systems that had their share of problems with the plastic roll cages. I had no problems in boxing up complete gear cases,transmissions,etc and receiving a replacement in a matter of days. I don't know if it was because of all the years we were a dealer and had a good relationship with Polaris and the people, or because we were the first authorized dealer in North Texas that only sold Polaris atvs and not a multi line atv dealer, or what? Granted come November I will be out of the business for two years,but I don't think Polaris Industries has changed that much.I think it comes down to how much the dealer tries to help consumers or even test riders like you and how trained the staff are. Plus I can't count the times I had items that were even out of warranty covered. Just my old worn out again OPT