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Discussion Starter #1
Brother had a noise and vibration in the front of his brand new xp 1000 so we got to checking it out and narrowed it down to the front diff with a mechanics stethoscope. Pulled it apart along with a 2014 xp1000 diff i installed on my old xp900 that sounded good. After comparing to 2 diffs found that the 2014 had .026 gap between the pinion gear and housing. The 2015 only had .010 gap. Found a shim on the 2015 diff between the pinion bearings and pinion gear. Pulled the shim out which gave it the same amount of clearance as the 2014. Put diff back together, installed it in rzr and the noise and vibration is 100 percent gone.
 

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Great info!!!
 

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Great info! Just looked at the service manual and they don't even show this washer in the parts diagram for the front diff. I wonder why it's even there? Did you happen to compare the actual pinion gear to see if one was longer than the other? Correct me if I'm wrong but by placing the washer on the the other side of the bearing you are pulling the gear further out of the housing?
 

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Great info! Just looked at the service manual and they don't even show this washer in the parts diagram for the front diff. I wonder why it's even there? Did you happen to compare the actual pinion gear to see if one was longer than the other? Correct me if I'm wrong but by placing the washer on the the other side of the bearing you are pulling the gear further out of the housing?
It was my Rzr we were working on.
To answer your question, by having the shim installed between the bearing and the pinion gear it actually pushes the gear further into mesh with the ring gear because the outer race of the bearing seats in the housing and the inner rides on the pinion gear.
It was an extreme difference in sound and feel just on the bench but when we test drove it with the shim moved to the back of the bearing it was night and day.
 

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Great info! Just looked at the service manual and they don't even show this washer in the parts diagram for the front diff. I wonder why it's even there? Did you happen to compare the actual pinion gear to see if one was longer than the other? Correct me if I'm wrong but by placing the washer on the the other side of the bearing you are pulling the gear further out of the housing?
It was my Rzr we were working on.
To answer your question, by having the shim installed between the bearing and the pinion gear it actually pushes the gear further into mesh with the ring gear because the outer race of the bearing seats in the housing and the inner rides on the pinion gear.
It was an extreme difference in sound and feel just on the bench but when we test drove it with the shim moved to the back of the bearing it was night and day.
Did you use gear marking compound to check tooth engagement before & after to verify where the gear contact was?
No, we were just experimenting and testing and it smoothed it out, I suppose there is around .026 worth of room to set pinion depth with if someone wanted to try to dial it in better. Maybe worth a try. Iright now I am just happy it is smooth and quiet.
I had an old xp900 diff that was junk and took the pinion out of it. I found that it didn't have this shim and the bearing was pressed all the way against the pinion gear like We did mine.
 

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That would very difficult to do. Technically your supposed to manually turn the ring gear so that it turns the pinion gear. Your also supposed to apply slight resistance to the pinion shaft while turning the ring gear. All of which would be nearly impossible on a Hilliard style differential.

Sent from my SCH-I535 using Tapatalk 2
 

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Right, your are using the pinion shaft to turn the ring gear. Which is backwards from how contact pattern is supposed to be done. Or at least how every manual I have says to do it.

Also, have you been able to actually locate any documentation on what proper pattern of a straight cut cast gear set is? Unfortunately with the irregularity of the teeth on the ring and pinion I don't think you will ever be able to set these up using a contact pattern based method. The contact is going to vary wildly causing you to chase your tail.

In my opinion setting the backlash with a dial indicator, or good ol fashioned "feel" is the best or only option for determining proper pinion depth.

Glad your experimenting though.
 

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Not to step on toes....

Most folks couldn't begin to follow what you two are "talking" about, some of us can however. Just my 2c, would be a HUGE deal if we could figure out a fix for this front diff issue and knowledge like yours is greatly appreciated. Its why I joined these forums. It sucks to have two folks with your all's knowledge and just not work together on it.


anyway, back to the topic of this thread
 

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Discussion Starter #16
In my opinion a front diff is going to wear out faster if it is vibrating and rattling so bad that it making driving a brand new rzr not enjoyable. We tried some different things on the bench and pulling the shim made it smooth and quit which in turn makes driving the rzr enjoyble. Figured we would take our chances.
 

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Not to step on toes....

Most folks couldn't begin to follow what you two are "talking" about, some of us can however. Just my 2c, would be a HUGE deal if we could figure out a fix for this front diff issue and knowledge like yours is greatly appreciated. Its why I joined these forums. It sucks to have two folks with your all's knowledge and just not work together on it.


anyway, back to the topic of this thread
We just do not want to argue at this point as we too have been able to make head way with the noise problem and at the same time maintain proper I tooth contact and we did not move the pinion .026 away from center line to do it. As soon as our Aluminum Sprague Carrier is done and installed we will let everyone know what the real fix is for all the short comings with this diff. Now I have to get back to work .
Disclaimer: we are not telling everyone to run out and tear their diff apart. We just wanted to share what we learned by comparing a "familiar stock" 14 differential with these noisy diffs that have been discussed. We don't claim to be differential experts, only desperate Rzr enthusiasts that wanted a more enjoyable ride. I do believe that this was an assembly line mistake and I DO NOT believe that Polaris is setting individual pinion depth on each differential. Case in point is the xp900 has no room to shim either direction.

Just my .02.
 

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Discussion Starter #18
To get back to my original post we will keep posting an update on progess. And to be clear the pinion only got move .016 to end up with .026 clearance between pinion gear and the housing. Simple test and didnt cost any money to buy parts that may or may not fix the problem. If anyone else tries this please keep us posted on your results so we can all maybe benefit from this.
 

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Shade tree mechanic? Shoot son, I work in a mud puddle by a plywood hut under an overpass. Lol.

Thanks for sharing your findings XPRT. Sounds like your new aluminum Sprague will be the ultimate fix.
 

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Not to step on toes....

Most folks couldn't begin to follow what you two are "talking" about, some of us can however. Just my 2c, would be a HUGE deal if we could figure out a fix for this front diff issue and knowledge like yours is greatly appreciated. Its why I joined these forums. It sucks to have two folks with your all's knowledge and just not work together on it.


anyway, back to the topic of this thread
We just do not want to argue at this point as we too have been able to make head way with the noise problem and at the same time maintain proper I tooth contact and we did not move the pinion .026 away from center line to do it. As soon as our Aluminum Sprague Carrier is done and installed we will let everyone know what the real fix is for all the short comings with this diff. Now I have to get back to work .
Disclaimer: we are not telling everyone to run out and tear their diff apart. We just wanted to share what we learned by comparing a "familiar stock" 14 differential with these noisy diffs that have been discussed. We don't claim to be differential experts, only desperate Rzr enthusiasts that wanted a more enjoyable ride. I do believe that this was an assembly line mistake and I DO NOT believe that Polaris is setting individual pinion depth on each differential. Case in point is the xp900 has no room to shim either direction.

Just my .02.

It was designed by "experts" and engineers.........

Most of the time the fix for these types of issues comes from people like you. Willing to try things that won't work according to "brilliant engineers". Lol


Thanks for sharing your findings. Hopefully this will end up fixing at least some noisy differentials.
 
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