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Discussion Starter · #1 ·
Looking for some help with a front diff not engaging on a 2021 Turbo S4, 1600 miles. Diff wouldn't lock 99% of the time. Voltage to the diff tested spot on. But the amp draw seems low at 0.5 amps +/-. Ran power directly to a separate fully charged battery to isolate the issue to the diff only. Amp draw is the same. Electromagnet ohms at 22.3. Removed the diff to inspect internals. Every component inside is very clean and no visible blemishes on anything. The only thing I notice is how weak the magnet is. I can easily spin the armature plate with two fingers with a 13v battery directly connected. There is no way that the armature has enough magnetic strength to overcome the return springs. This must be a weak armature magnet. Can anyone tell me what amperage I should be seeing on a known good armature when energized? I’d really appreciate any advice, comments, or technical assistance before I drop some dollars on this thing.

Thanks!
 

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12v / 23.3ohms = 0.54A exactly what it should be. If you can spin the armature plate with voltage applied it's probably warped. If the plate is not absolutely flat where it's makes the most contact patch it will not engage correctly.
 

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Discussion Starter · #4 ·
I found the actual problem shortly after posting for help. Thought I'd post the end result. As you said RZR_Joe, the plate was warped, and appreciate you verifying the electrical readings. Thankfully the $650 electromagnet was not the problem on this one. After some tinkering around with it on the bench. Found the armature plate had a slight convex/concave shape. Makes sense because it is a piece of stamped sheet metal. The side that contacts the electromagnet was the concave side and would not hold strong enough to engage the sprague. If I flipped it over it was a day & night difference in holding strength. Since I was in a bind and to save my trip I did what I had to do. No time to order parts. The armature plate has six cogs and the small one is clocked a little different than the larger ones. The small cog prevents it from seating into the plastic torsion retainer if trying to install it backwards. So I filed it off. Put the whole thing back together and had a great trip. The way I see it, 5 cogs are plenty strong enough to get the job done. We'll see how long it lasts because I don't have the motivation to do this again unless it quits working.
I want to give a special shout-out and "THANKS" to the Polaris engineers. The entire front end of the machine is built around the front diff in every possible way. I thoroughly "enjoyed" disassembling so much and putting it back together for a minor problem. All the while, discovering my acuity and application of appropriate eloquent shop talk is above average.
That's sarcasm PoPo. You can do better than this.
 

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I found the actual problem shortly after posting for help. Thought I'd post the end result. As you said RZR_Joe, the plate was warped, and appreciate you verifying the electrical readings. Thankfully the $650 electromagnet was not the problem on this one. After some tinkering around with it on the bench. Found the armature plate had a slight convex/concave shape. Makes sense because it is a piece of stamped sheet metal. The side that contacts the electromagnet was the concave side and would not hold strong enough to engage the sprague. If I flipped it over it was a day & night difference in holding strength. Since I was in a bind and to save my trip I did what I had to do. No time to order parts. The armature plate has six cogs and the small one is clocked a little different than the larger ones. The small cog prevents it from seating into the plastic torsion retainer if trying to install it backwards. So I filed it off. Put the whole thing back together and had a great trip. The way I see it, 5 cogs are plenty strong enough to get the job done. We'll see how long it lasts because I don't have the motivation to do this again unless it quits working.
I want to give a special shout-out and "THANKS" to the Polaris engineers. The entire front end of the machine is built around the front diff in every possible way. I thoroughly "enjoyed" disassembling so much and putting it back together for a minor problem. All the while, discovering my acuity and application of appropriate eloquent shop talk is above average.
That's sarcasm PoPo. You can do better than this.
To take apart and reassemble the front end for one little problem is extremely inconvenient. Let me ask: Does this problem often occur on other units? It's just that I'm looking for a model right now, so I'm wondering.
 

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Discussion Starter · #10 ·
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