Final dive venting revisited

[Airtrax]

I read the posts about venting the final drive. Now mine is off for servicing and I am reluctant to start drilling holes.

It doesn't have a leak, however, will accumulate some light grime under the housing over time.

So, if this vent hole is so important, why didn't it come pre-drilled from the factory? And what keeps all that lubricant from coming out while running?

How many have done this? Thanks for the replies.

More to come on drive shaft lubrication soon.

[Rhinestone Kawboy]

I read the posts about venting the final drive. Now mine is off for servicing and I am reluctant to start drilling holes.

It doesn't have a leak, however, will accumulate some light grime under the housing over time.

So, if this vent hole is so important, why didn't it come pre-drilled from the factory? And what keeps all that lubricant from coming out while running?

How many have done this? Thanks for the replies.

More to come on drive shaft lubrication soon.

For most of the Voyager production years, this vent hole did come stock. However, after some began experiencing more severe oil leaks from the rear end, it was thought to plug this hole. Then the cause of the oil leaks was found to be excessive oil in the rear end, and without the vent hole, excess pressure could built up and sometimes blow the oil seals, so the idea of vent holes (with proper rear end oil level) was again suggested. Oil in the rear end (80-90 wt. hypoid) should be no higher than 1/4 inch below the oil fill hole on the upper side of the rear end. You may have a little light grime sticking on the oil mist on the rear end housing, just remove it occationally and you shouldn't have a problem.

[Charlie from Illinois]

I drilled my on my 03 and have had no problems with leaking coming from it.

[The Count]

I have my 02 drilled with no problems.

[dlehning]

I would like to know what size drill bit is used to vent
the rear drive. I have two Voyagers neither of which
is vented. An answer would be appreciated. Jayhawk

[Scott-(Altoona, PA)]

Go to http://abbikeboard.com/phpBB2/viewtopic ... inal+drive and read over this topic. There is the information that you are asking and most likely information that you will be asking that you have'nt thought of yet on this topic.

[Spike]

Since I had my final drive removed to service the drive shaft I decided to drill out where the vent hole was in older models. After doing that I blew air into the hole that I just drilled and then found out that the rear end also vents out through a hole in the pinion shaft so I guess all I have now is an added vent. I guess it's possible that when they no longer had the hole in the rear end case they then vented out through a hole in the pinion shaft. I gess there is no longer a need to drill out this hole for venting.

[Charlie from Illinois]

I never knew that Spike. Thanks for the info.

[LASER917]

Spike75
When you pulled the final drive, did you have some rear gear lube in the driveshaft splines, I am just wondering if it works the same as a 1st generation Yamaha Venture. The hole in the pinion gear is there to allow rear lube to lubricate the splines of the driveshaft.

[Spike]

There was grease on the splines so it was hard to tell if there was a mixture of rear end lube with the grease or not. I guess that technically if they were relying on pressure in the gear case to force a little lube up to the splines you have now defeated that possibility when you drilled out the hole. I guess now I will have to wait until the next tire change and see if there is still a lot of grease in the splines. My bike had 83,000 miles on it and the drive shaft had never been serviced. It was still in very good condition.

[Mr Jensee]

This morning when I moved the Voyager I discovered a good amount of oil on the floor of the garage and when I traced it back it looks like the seals on my final drive may have blown. I don't know how to actually tell without removing the rear wheel and disassemble the drive shaft casing. Bummer. There is oil all over the final drive hub, all over my wheel. Tomorrow I plan to remove the saddle bags and inspect this closer. I am wondering if I should have drilled out that dang hole now....

[bikerking.biz]

I would probably have to say yes. Also make sure you or the bike shop is not putting too much oil in the rear end. No more than a 1/4 " below the oil fill hole with 85-90wt. oil.

[Mr Jensee]

I haven't dealt with a bike shop. I checked the oil level when I got the bike with 20,300 miles on it in January. Since then the gear oil is the only fluid I have yet to change out. Put new tires on it a couple months ago while I had the rear wheel off I greased the splines and checked the levels. I have not ridden it much the last few weeks and no long trips since I got it. I was just wondering why it decided to go south on me now. The bike was in excellent condition when I got it. If the seals now need changing I am planning to do the work myself or have a friend of mine tackle it who regularly repairs Goldwings who lives near by. I'm just wondering that if drilling the hole will fix the leak or do the seals now have to be changed.

[MTN99]

Mr. Jensee,
I developed the same leak on our 99 a while back, drilled the diff as per the following from "The Masked Rider" and have not had a problem since.......( here it is copied from the abbikeboard site... Thanks guys)

" Drilling a final drive vent hole. Fritz Wells

After you remove the rear wheel, cover the final drive gear
with a rag so you don't get chips of metal on it. Myself,
I use masking tape to tape a rage to the final drive face
to make SURE no chip get on the gear. A little note,,, look
at the amount of grease on the gear. Don't use anymore than
that amount. I've seen too many mechanics putting WAY TOO
much grease on that gear. It doesn't take much grease to
work. If you use too much grease, when the final drive builds
up heat, this grease will turn to an oil and will be
thrown outward against the inside of the hub and leak out onto
the wheel and tire. Oil on tires are not a lot of fun. :O)

Use a 1/16th drill bit. measure back from the tip of the
drill bit about 3/16th to 1/4 inch and wrap a piece of
electrical tape around that point. This is to give you a guide as
to how far to drill into the final drive case. Its just so
you don't drill through the out side of the case. The bit
will go in more than that but its a good reminder to not
drill too far.

NOTE: I use a shop vac and hold the hose up to the drill
bit while I'm drilling. Most of the time it will suck up all
the chips and none will even fall on the rag. No matal
chips should go into the final drive case because it the nature
of the drill bit to pull metal out away from the hole. You
can use a small piece of wire to poke in the hole to make
sure it was drilled all the way through. Even in the worst
case scenario that a small chip would get into the final
drive, it would only get eaten up in the gears. You should
have no problems as long as you pay attention. "


Hope this helps

[Mr Jensee]

Thanks. I just checked the oil in the differential and I am inclined to think this just may well be the grease I packed around the spline earlier when I changed the tires. The reason I say that when I opened the filler hole on the differential the oil was not only to the specified level but was so clean it looked like it was changed yesterday. I cleaned everything up and will monitor it for the rest of this time home and will drill the hole out next time home later in the month. I have some obligations I need to take care of this weekend and I go back to work (7and 7) on Tuesday. Thanks for the replies, guys.

[Nathan (South Carolina)]

Mr Jensee,
You may be right in your assumption. I haven't seen any seals go bad near the wheel. Most go bad near the front of the differential and leak near the rear of the engine on the left side.