# Front differential Help!!



## luckyc1423 (Nov 23, 2011)

*2009 brute force 750*
*Background*
About 5-6 months ago I let a friend drive my four wheeler (I have a side by side that I normally dirve). Everything was going fine then we started to hit some decent mud. When going through the mudholes he would get stick and keep hitting the gas and you would just hear a "click click click click" sound. All day long in the mud it would click (only in 4 WD 2 WD it was fine). I was hoping my four wheel drive was not messed hope, I was hoping mud or something was making it slip.

So I gave her a good wash down, and put it in four wheel drive, and tried to climb a wall to see if the four wheel drive would click and everything seemed fine.

Well fastforward about 6 months, I took the four wheeler out for the first time in a while.
The four wheel drive was fine, no clicking. The issue was the steering was messed up. I would be driving along and it would be very difficult to turn right, I would have to jiggle the steering wheel to free up the issue and then the bike would turn fine. Then a few moments later the bike would be difficult to turn again. It would go in and out of being difficult to turn all day long.


I took the bike home, and went riding again the following weekend on the bike. The steering still had the same issue but now I was getting a clanking sound when I turned like my CV boot was bad.
I drove all day like that, and the last few days I have been digging into the bike to figure out the issue.

The front right wheel bearings looked bad so I replaced the entire front right knuckle with a used knuckle I found on craigslist (bearings seemed to be in good shape on the used part).

I also replaced both front axles, I drained the front diff, and put new front diff fluid in.

While jacked up, after i replaced the parts, the bike would turn back and forth no problem.

But what is scaring me is I will spin the front left tire forward and the front right tire only spins part of the time (when it wants to). If I spin the front left tire really fast I hear a clicking or grinding sound coming from the diff area. It sounds like the teethe are trying to engage. 
I then spin the wheel backwards and about 80% of the time both tires spin at the same rate of speed.

Then I engage the diff locker (yellow lever) and turn the front left tire and still the front right tire only spins when it wants to. I hear the same sound like the teethe are trying to engage.

My fear is, my buddy might have messed up my front diff 6 months ago. I sure hope not, I sure hope this is normal while jacked up??

**I didnt think my buddy having the clicking noise 6 months ago was a big deal since it never clicked again while going through mud holes. But me having it jacked up and hearing the teethe trying to engage has me worried he might have screwed something up.



****note I am not a mechanic, this is the first time I have ever changed axles before. I am pretty sure I got the axle properly seated in the diff.

---------- Post added at 03:46 PM ---------- Previous post was at 03:40 PM ----------

I guess the questions are.
While jacked up:
1) if i spin one tire forward should the other tire spin as well.
2) If i spine one tire backwards should the other tire spin as well
3) if i spin the tire fast should i be hearing a noise like teethe are trying to catch
4) if i engage the diff lever (while the back is NOT started) and spin one tire should the other tire spin at the same rate


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## adamwedge (Jan 4, 2014)

When you spin the wheels of the ground, is there any binding or anything from the diff? Like pieces are catching in between gears?


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## luckyc1423 (Nov 23, 2011)

Video link below.


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## adamwedge (Jan 4, 2014)

Either that axle is not in all the way, or spider gears are gone. When you drained fluid you didn't notice any metal or chunks of gears?


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## luckyc1423 (Nov 23, 2011)

No metal, I dunno how I would see chunks but it was just normal 10w-40 oil that looked alittle old.

I am not sure how to get the axles in further, I will take another short video so you can see if the axles are in far enough.

---------- Post added at 04:55 PM ---------- Previous post was at 04:55 PM ----------

what are spider gears? how do you replace those?

---------- Post added at 05:04 PM ---------- Previous post was at 04:55 PM ----------

axle gap video. this is 2009 brute force 750, installed rhino axles.
first part of video shows front right axle. second part shows front left axle.


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## adamwedge (Jan 4, 2014)

Axles appear to be in all the way... 

The hard steering in 2wd is a tell tale sign of front diff grenaded. Let me dig up a link from when mine went. Prolly pull it out and see what's what. Clanking sounds are never good lol

---------- Post added at 07:14 PM ---------- Previous post was at 07:09 PM ----------

 Front differential disassembly - MudInMyBlood Forums


If you look at the pics, that's what was causing my bound up steering.


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## luckyc1423 (Nov 23, 2011)

What kind of cost am I looking at?

Can someone that is not to mechanically inclined handle this?

Are we sure its the front diff? Hate to start taking it off and come to find out its not the diff?

Just to be clear, if I turn from left tire front right tire should turn with it? Since it doesn't that means the diff is done?


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## adamwedge (Jan 4, 2014)

More so than anything IMO, the bound up steering would be an indicator for me. 

I know both of my wheels spin when they're off the ground....

Don't think it could be anything but the diff going on based on what you're telling us. 

Cost just kind of depends what it needs. Tearing it into it isn't that bad. Getting it out is the fun part! lol

To be clear, steering is bound up in 2wd, NOT 4wd correct?


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## mryntry (Nov 27, 2009)

I had almost identical situation. A bad seal let the oil leak out over time in the front dif. Over the winter. Pull axel out on the left side so you can see in. The bearings were shot from lack of oil. You will need a diff rebuild kit.


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## luckyc1423 (Nov 23, 2011)

So odds are my diff is messed up?

What kind of cost am I looking at?

I def don't want to dig into the diff and that not be te issue, we are pretty confident it is the issue?

---------- Post added at 12:45 PM ---------- Previous post was at 12:44 PM ----------

Yes steering is hard to turn while in 2wd going about 10-15 mph in a straight line.

When in trails or mud I never have the steerin issue


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## adamwedge (Jan 4, 2014)

Does it pull in 4 wheel? Like, the front wheels are powered when 4 wheel is engaged?


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## luckyc1423 (Nov 23, 2011)

While driving slow through mud in 4wd I haven't had any issues


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## luckyc1423 (Nov 23, 2011)

Ok, I have the diff out and tore down. I have some chipped gears.

The spyder gears were seazing up not turning all the time because the chipped pieces were getting in between the spider gears not allowing them to move.

The question is, what is this housing called? Can I just buy this housing with the spider gears in the housing? Or do I have to tear down this housing to get to the individual spider gears?

I cant figure out how to open this housing.


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## luckyc1423 (Nov 23, 2011)

Question two, there are scuff marks on the housing. is this normal, should this be happening, do i have another issue?


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## dman66 (Feb 20, 2011)

Check on here , kawieriders , and ebay for front differential . There should be some parts up for sale . Then buy the other parts new form a parts supply house . Then check into the spider mod which will help with lubricating the spider gear shafts .


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## luckyc1423 (Nov 23, 2011)

Well I got it open and found the broken gears.

Everything else seemed in good working order. I assume I just need to replace the gears? No need to replace anything else that looks good?

Were fan I buy these?


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## dman66 (Feb 20, 2011)

Check my post , or buy new . Buy new spider gears and new shafts for the gears , and do the spider mod to the spider gear shafts .

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## Rosen32 (Jan 15, 2014)

I have a complete, new bearing seal kit and some good (used) internal parts (not spider gears)if you are interested. Mine did something similar and I just went with a used diff from a member on here rather than rebuild mine.

1-320-980-8508
Cory Rosen.


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## chopermech (Dec 3, 2012)

There are some things you can do to prevent this:

1) cryogenically treat the gears
2) good lubrication such as use of clean fluid with no water and mud contamination with an adequate oil level
3) some housings Kawi used allowed for the use of two seals on the CV cup. You can install the second seal in reverse direction to help keep water out
4) keep good seals
5) use of a magnetic plug
6) use a vent bellows instead of a vent line
7) use a CV cup cooling fin sleeve like the can-am maverick has. This will help keep the internal temp down by a conduction heat transfer
8) do not jump or suddenly load up the tires with 4wd engaged. 

I am considering dedicating a part of my shop to strictly do differential rebuilds and mods. Cost would be around $130 labor and whatever the retail price of the parts is what you pay.


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## adamwedge (Jan 4, 2014)

New gears are 180ish at Motosport. Are the large gears damaged as well? Definitely inspect them good, look for hairline cracks at the base of each tooth. I ended up finding a used diff on ebay; already tore down for cheap. Keep looking. Glad you found the problem. Thought we we're going in the right direction.


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## adamwedge (Jan 4, 2014)

1423, you get the beast back in working order? Progress report?


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## Finest Racing (Feb 17, 2015)

Chopermech, if you were near me - I would drop my 09 off. Front diff not working.


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