Hey guys, new here, but far from new to ATVs. I’ve owned a 2005 Kodiak 450 for a couple of years, I bought it from the original owner who unfortunately, left the ATV outside rather than store it inside. When I bought it, it only had 3800 kms on it and it only has 4200 on it now. A couple of weeks ago while servicing all of my small engine equipment, I changed all the oils on the Kodiak, which I’ve done at least twice before that. Imagine the look on my face when I pull the drain bolt for the rear differential and not a drop of gear oil comes out! Long story short, it was still turning so I pulled it out of the ATV and ordered an All Balls differential oil and bearing rebuild kit for it. I searched clear across Canada for a used differential and only found two that likely would have needed to be rebuilt too. Used diffs were $400+tax/shipping and seals/bearings they might have possibly needed. The bearing kit was only $140 and rebuilding it myself, I knew what I would have when finished. I took it apart myself, the gears and case were still in good condition, however only half of the pinion bearing was there and the other bearings were not in good shape either. Knowing the crown gear had to be pressed off to replace that bearing, I let a friend who runs an ATV repair shop do the rebuild for me. Now, the day he rebuilt it, he called me and said he wasn’t 100% sure how the pinion seal went in. When I took it apart, only the rubber part of the seal came out and the steel ring was unknowingly left inside the bearing retainer, however we did not know that and at first, thought it was part of the retainer. Before we had figured it out, he tried to tap the seal in from the threaded side of the retainer, using a similar sized socket, which he knew didn’t seem right but couldn’t figure any other way to install it with the old seal ring still there. The new seal was 3-4mm bigger in diameter and there was no way it would fit, so after 2 or 3 hits, he said, this can’t be right, we must be missing something. That did not appear to damage the seal, and shortly after, he took a punch and removed the rest of the old seal and we realized our error. I should add to this that I have the factory Yamaha Service manual which only shows reassembly of the straight axle differential and not the IRS differential, which is different. So we managed to get the seal in and finished rebuilding the differential. Everything felt fine, the yoke felt tight but still turned and when I re-installed it on the ATV, everything seemed to be ok, up until this morning, which is a week after it was rebuilt. I’ve only driven it about 5 kms total since rebuild and this morning I was shocked to find a puddle of differential oil on the floor in my garage. On closer inspection, I could tell it had come out around the seal in the pinion gear/bearing retainer and there was also gear oil all over the yoke of the driveshaft.

My question is, what if anything, did we do wrong? I know obviously we screwed up on the old seal and trying to tap the new seal in. Even though, visually it didn’t seem to damage the seal. But I wonder if we may have stretched it, preventing it from sealing properly. Does that seal need to be greased where it meets the shaft before the shaft goes in? Or possibly greased around the edge of the seal where it meets the differential housing? On the straight axle differential in the manual, it shows greasing the seal, but as I said, there is no diagram of the IRS. I think when he put the seal in, he tapped it into the retainer and then put the yoke through it. The seal fits perfectly on the yoke end, I’m wondering if it shouldn’t have been installed on the yoke first, and then tightened down with the nut on the pinion shaft? Or would that really have made any difference? Can someone show me a proper manual that actually has the IRS differential re-assembly in it? The manual I have says March 2002 First Edition right after the cover page, so I’m wondering if there’s a newer edition manual that I haven’t found. I’ll post a link of a parts breakdown/diagram so that you can get a visual idea of what I’m talking about, if you don’t happen to be familiar with this differential, as we were.

http://www.yamahapartspitstop.com/oe…d7/drive-shaft

#13 is the pinion seal that I’m talking about. #14 was included with the kit, but not replaced as the old o-ring was in good condition. It’s placement is not clear in the diagram, but it is installed at the top of the bearing retainer.

Thanks for any help.