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Discussion Starter · #1 ·
So over many yrs with may Polaris products, being a victim of 800 front diff failures due to improper welded u-joint alignment on the prop shaft, and the fact it wasn't designed for an 800, I have been thinking. The 900 has treated me very well in the diff dept but prop shafts are still a joke. I know this is just gravy selling a customer a $600 prop shaft when the u-joints fail but good engineering would eliminate this. Why have a shaft with splines on the end which is supposed to move with frame flexing. If an engineer had your best interest and longevity in design they would have put in a CV type shaft that clamped onto the shafts of the diff and rear end . This would eliminate play and also the CV joint could take the sliding motion of the frame flexing. There wouldn't be U joints exposed to the elements and be a sealed greased unit capable of all environments. This won't sell parts though and make extra profit the way I see it so my next prop shaft when my new one comes in I will be engineering a setup with CV ends
 

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Probably for the same reason auto manufacturers use ujoints on heavy duty applications like trucks and use cvjoints on light duty applications like cars, ujoints are stronger than cvjoints. cvjoints only outperform ujoints because they can be run at larger angle offsets. Frame flex isn't enough movement to warrant cvjoints.
 

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Discussion Starter · #4 ·
Can put way more Hp in a car with CV joints than any ranger will put out that last 200,000 km. Frame flex is enough to make them put a spline shaft you are supposed to grease so it can have movement and get sloppy over time. U joints and water don't mix. If there was ever an application that required CV joints, the prop shaft driving the front diff is one. If the shaft didn't need to move on the tranny output splines they would have put a roll pin in like the prop shaft has at front diff. There is flex in everything and a CV shaft would alleviate all this and handle the prop shaft angle better I think. I will have to look on the online parts catalogue to see the CV prop shaft. I hope my 2021 1000 premium has one.
 

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If cvjoints were the superior solution, you would see it in aftermarket racing applications on turbo powered RZRs and generals.

Water is worse with cvjoints, hence they have rubber boots.

To get a cvjoint that is as strong as a ujoint would require 2-3 times the size.
 

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Discussion Starter · #6 ·
I see the 2017's have CV but my 2021 I ordered has the failing prop shaft with u-joints. The CV's don't look huge by any means on the browse Polaris parts catalogue Too much money to be made selling new shafts I guess. The idea that water is worse with CV joints is false. U-joints that don't grease will fail in mud and water if not greasable.. I haven't had a Polaris ATV or SxS that I haven't had u-joint failures due to monkeys at the factory welding the yokes out of time or from just rust in the yokes. When these things start getting stiff or out of line it just eats the splines out. Or like in the case of my 800 ranger with 1100 miles the front diff. That one was from yokes being welded a good 5 degrees out of line. Took the pinion shaft out and because warranty was off I had to pay for the diff and the prop shaft from poor workmanship. My experience with Polaris has been good for the most part but their prop shaft angles on early models and their poor workmanship have cost me many $$ over the yrs. I had a 500 Magnum yrs ago that had a prop shaft welded improperly as well. 2200 miles and the tranny side splines had slop with weekly greasing when using it. I have a good notion to take the prop shaft out on my new ordered one and check the alignment. How anyone can weld a yoke out of line with a jig makes me wonder if they even use a jig. With 2 out of 7 I purchased having bad workmanship on prop shafts over the last 25 yrs something makes me think this is just a money grab or complete stupidity.
 

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The shaft angles at the transmission and front differential are not parallel so they can never be aligned correctly for speed balance with Cardan joints.
Bottom line, they will always be unbalanced unless you use cv joints.
 

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I did a search and this is the first one to come up.
There might be others.
 

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Polaris has been making improvements over the years on that alignment problem but not all models get the improvements at the same time.
I don't know where the new Rangers are in that time frame.
 
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