If you’ve been around the AWD system Polaris claims is “On The Fly” long enough or been a part of any number of Polaris forums, by now I’m sure you’ve heard of the dreadful “Exploding Front Diff”.
There is much debate on this subject about what causes it and what you can do to avoid it.
I have a theory, this theory is derived from all experiences of those I’ve read about as well as my own personal experiences.
First I’ll tell you the three categories I think most occurrences fall into:
1. Switching the machine into AWD “On The Fly” while rear tires are spinning at a rate the front diff cannot handle.
2. Running the machine in AWD, riding in a state where the AWD system is currently not engaged but then the operator mashes the throttle causing the rear tires to spin at a rate that the front diff cannot handle. If the throttle is smashed to harsh the computer doesn’t recognize the spin soon enough and before it can engage, the machine is already at 3k rpm (plus) and the rest is history.
3. Some are breaking in 2WD without the operator ever touching the AWD system at all. In this case, one would conclude that the front diff had to engage on its own somehow.
Ok, from everything I’ve read, everyone seems to think the diff cover is what is failing causing the internals to let go, while this may be the case, I’m not 100% sold on the fact that it Is where the problem begins or ends.
But before we jump into that let’s first address how the AWD system could engage on its own without switching into AWD mode.
Last year I took my quad in for what I thought was a regular service only to find out I had front diff issues. My diff cover was in tact, but the machine (while all four corners were on jack stands) was intermittently engaging AWD while the switch was in 2WD mode. The dealer then unplugged the diff, cutting any information it could be receiving from the ecu and AWD was still engaging. Impossible right, not so... In my case, there was a part that was broken inside the diff, they told me it was a magnet of sort. Not knowing exactly what is inside a front diff, I thought, ok...sounds weird, but ok. Now, this would explain 2 things; 1. The diff engaging at any given time because the magnet is broken allowing AWD to engage whether plugged in or not and 2. Now the machine may as well be in AWD all the time as it is acting as such anyway which brings me to my theory:
The front diff cover isn’t breaking first causing the internals to fail, it’s the exact opposite.
- In scenario #1 at the top, this to me is common sense, “OTF” AWD on an ATV is flat out stupid. You are asking for problems. If the internals were forged, that’d be one thing, but I think what we’d find if we had “black boxes” on these ATVs is that in the cases where the diff blows while switching on the fly, the rear wheels are spinning at a rate and the rpms are at a rate that the internals just cannot hold up.
- In scenario #2 at the top, although in AWD already, I don’t believe our ECUs are sending the information fast enough. When the operator smashes the throttle very quickly or if in snow or on ice the wheels spin so quickly that by the time the diff gets the info there’s too much momentum built up for the diff to handle the torque.
- In scenario #3, per my experience, I think there is a pre-existing condition inside the diff where it isn’t functioning properly allowing the diff to engage at any given time and the first 2 scenarios then come into play.
ANY WAY YOU SLICE IT, IT HAS TO DO WITH 2 THINGS:
1. The internals aren’t strong enough to handle the torque placed on them in the first 2 scenarios, and...
2. The technology/ecu programming all the way around is in its infancy and just isn’t quite dialed in yet.
A lot of these stories take place while riding in the snow. In snow you’re vulnerable to quick slips and spiking rpms. The ecu programming just isn’t quite there yet.
Once the internals are compromised the diff cover has no alternative but to give way. I think the updated covers keep the internals in tact, but I don’t think they’re solving our problems entirely, momentarily yes, but I’d be willing to bet eventually the internals break without destroying the updated cover.
This isn’t a testimony of facts, it is simply my take on what I think is happening.
For now, as far as I can tell, the only form of protection we have is the diff cover and never switching to AWD “OTF”. When you are in AWD, treat it as though you’re in AWD. Take it easy and hope for the best every time you ride.
