Im not sure about an 03 but I know our old school 90`s Kodiaks/big bears they were famous for the yoke nut loosening off allowing the yoke to slop around a slight bit causing minor to major oil leaks. Im willing to bet your seal isn't shot and its a matter of tightening the rear yoke nut.

 

How much ya putting up? :rocker:

Ya know I did read that a few other places but I figured if i was going to have it apart that much I might as well replace the seal. I wonder if I should tear it apart and see, might save me the week of wait for parts.

 

You better not take his bet. I had the very same issue on my '91 and it was a loose nut - about a full turn loose. Tightened it up and it is great now.

You are looking at a job there because you have to remove the entire swingarm, which also involves removing the axle and pumpkin. Some of those bolts may be difficult to get off.

You may also want to investigate what it takes to replace the seal because I was told by others that you have to remove the transfer case and split it because the seal is pressed from the inside. I was hoping that wasn't true because I didn't want to get into that and luckily my problem was just the loose nut.

Good Luck!

 

2003 is a little different set up. I believe they don't have the external t-case like our 90`s have, yet rather they have all that stuff inside the engine case. Either way the seal is still gonna be a pain in the bum to get at.

 

ah hell, got my decades screwed up. he said '03 and I was thinking 1993.

Either way, hope it isn't a big chore for ya.

 

Thanks guys, at least if the nut is loose I won't have the hassle of breaking it loose!!

Not looking forward to the job, I've already had a couple of bolts break when doing some other stuff to the quad. Sitting outside for 10 years without a bath will do that I guess.

 

Just an update, I got the job done last weekend. It took a while, wasn't too bad but I hope I don't have to do it again anytime soon. Hardest things were getting the rear shock pin off (it was frozen in there pretty good" and getting the new boot to seat correctly.

To be honest I'm not sure if the nut was loose or not. I tried to turn it by hand and it felt tight, I tried to wiggle the yoke and it seemed tight. But...when I put my impact gun on the nut to take it off, it came off with no resistance, my cheap HF impact gun spun it right off, which makes me think maybe it wasn't torqued on. But I replaced the seal regardless and so far so good.

 

That's good to hear. Sounds like you did a good job and it shouldn't be a problem again.

I noticed an oil spot under mine this weekend and my front yoke bolt must be loose again. I'll have to tear it down and do something this time to keep it tight on there longer.

 

I'll have to tear it down and do something this time to keep it tight on there longer.

weld it? lol

 

I don't mean to bring up an old thread, but this thread seems to be exactly what I'm looking for.

I was getting my 1997 Kodiak 400 ready for spring. I was in to process of checking the black rubber boot that runs from the engine to the rear diff. It was fine from the outside appearance (no tears or leaks), but when I took the boot clamps off a whole lot of oil came leaking out from inside the boot so the engine must be leaking oil past the drive shaft seal.

I bought this ATV used a little over a year ago. I'm assuming no one has ever removed the rubber boot clamps to check for leaks. I would say maybe 1/4 liter of oil came out, I'm sure there is a little more in there too. For a 17 year old ATV with only that much oil the leak must be very slow.

Where is this rear yoke nut you've guys tightened located? I've been looking at on-line parts diagrams and I cannot find it. I'm wondering if it might be called by a different name by Yamaha.

http://www.boats.net/parts/search/Ya...AFT/parts.html

 

wrong parts diagram! its the big nut that would be in front of the fwd arrow in that pic!

 

Ah, that be why I couldn't find it!

Part #51 then right?
1997 KODIAK 4WD - YFM400FWJ Yamaha ATV MIDDLE DRIVE GEAR Diagram and Parts

 

Okay, I pulled back the rubber boot and temporarily zip-tied it back to get a good look at this oil seal and yoke nut. The seal looks fine but there is no way to tell if it's leaking because its shot or the nut is loose. But the first step would be to check the nut.

There's not much room at all in there, but I think I can machine something up to tighten the yoke nut without having to take anything apart, but I need to know what size this nut is? Does anybody know? I'm thinking I can take just a regular deep socket and drill a hole thru it on the back end where the the ratchet would usually go. Once I get the socket on the nut, I could then slide a bent (to clear the metal housing) 6" tool steel rod into this hole and turn it maybe a 1/8 of a turn. Then I'd repeat this for a number of finger cramping times until I get it tight. Or I find out the nut never back out and I have to disassemble everything to change the seal.

Again, does anyone remember the size of this yoke nut?

Thanks.

 

Believe me or not but you will not get any kind of tool in there to tighten it up. There just is no room. The swingarm has to be removed to access the u-joint, and the u-joint taken apart.

 

I know what you mean, I looked at it for 1/2 hour thinking I should've just started pulling it apart already, but I'm gonna try it first as futile as it might turn out to be. If a machined down socket doesn't work, I can also try making a thin angled tool steel wrench. I can get access to the nut so that is not the problem. The problem is I will only be able to turn it maybe an 1/8 of a turn each time. And that's a big "maybe".

 

I don't have a Kodiak manual so I don't know for sure.
On the Grizzlies 450,660,700 some of the yokes and drive couples require Lok-tite on the nuts.

 

I am having the same issue on my 2001 Big Bear 400 4x4 I tore it down all the way to the rear u-joint but I cant get a socket/wrench in there to tighten the yolk nut. Do you guys have a way to tighten the yolk nut? Or do I have to take the U-joint off in order to get to it? If so whats the easiest way to do that? Plus can I remove and replace the rear main seal at this point instead of splitting the t-case?