# Front diff leaking at shaft....



## 2004sierraz71 (Feb 23, 2009)

So my buddies 08 750 started leaking out where the driveshaft connects to the front diff. There isnt nay play in it so its all good, but the seal is forsure bad. He never changes the fluids hardly and it is contaminated, so more then likely that is the cause. He has about 900mls on it and only changed it twice that i know of and ride water alot. Anyways, I have rebuilt several diffs but never messed with the pinion/shaft seal. Does it just pop out like the motor seals or what. I dont have either bike here so i cant look at them to see.I looked at it on babbitts and it looks as if it may just pop in, but you cant really tell with them pics. Thanks.


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## phreebsd (Dec 16, 2004)

it does.pull that shaft and pry it out. i gotta do mine as well.

as far as that never changed it but twice, i know someone else like that 
(and it aint me)


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## parkerexpress (Sep 7, 2009)

do yall have any pics or write-ups on the replacement? It sounds easy enough but I like visuals the first time I do a replacement in hopes i dont make something worse.


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## 1bigforeman (Jun 23, 2009)

Phreebsd has a video of changing the rear motor seal which is usually the problem. It works the same way. Compress the shaft and remove and then pry out the old seal. The new one pushes in flush.


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## crom a zone (Feb 25, 2010)

yes i just changed mine... its a 14mm nut inside take that out... andthen the sleeve or cone comes off and u will see the seal.. take seal out reinstal new one.... dont be scared when u go to put the new sleeve/cone thing in the grooves do not have to line up on the inside(its like 3 prongs) put it in and tighten 14mm nut and conect drive shaft and u are ready to ride.. took me about 15 min if that to change front pinon seal


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## Coolwizard (Feb 28, 2009)

How bad is it to change the left front diff seal?


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## crom a zone (Feb 25, 2010)

front left diff seal is very easy just like any other seal... but every time i pull my left axle out the needle bearings beind seal always go everywhere... dont worry they can not fall in diff just fin hem all pick them up and put them back in cage...


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## Coolwizard (Feb 28, 2009)

crom a zone said:


> front left diff seal is very easy just like any other seal... but every time i pull my left axle out the needle bearings beind seal always go everywhere... dont worry they can not fall in diff just fin hem all pick them up and put them back in cage...


Thanks, gotta change the left front and rear seal on the diff plus the rear engine seal on the '08 as soon as it warms up some.


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## cheapthrills (Apr 7, 2009)

Sorry if these seem like stupid questions but I need to do my front diff rear seal.
1) do you remove the drive shaft from both the engine and the front diff?
2) If so do you need to drain engine oil.
3) do you need to drain front diff oil ahead of this.

Croom a zone mentions " its a 14mm nut inside take that out... " whats that all about I don't see any large nusts involved

Thanks in advance for any help


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## drtj (May 3, 2009)

1) yes

2) no

3) yes

After u remove the axle there is a nut where the axle goes in the front diff. Remove it & then pry old seal out. While ur at it do a thorough cleaning/ flushing of front diff.


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## Waddaman (Oct 3, 2010)

Do you need a special nut to change the front diff seal, from the drive shaft?? also my compressing splines or whatever u call it is full of mud, how can i get a good grip on the drive to compress it???


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## rmax (Nov 21, 2009)

14mm hes refering to the socket size, not the nut size
the compression joint , i have had to put vice grips on the shaft an use a pry bar to get them compressed


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## brutemike (Mar 23, 2010)

Guys dont get confused here some of you are talking the small seal inside and some of you are talking about the bigger seal.


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## Waddaman (Oct 3, 2010)

I got it, forgot to post that lol. I was talking the big one.


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