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Upgraded to SE 6-speed: not a happy camper!


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Staff member
This is a consolidation of my post over on "Touring Models", so if you have seen it there, this will be familiar:

I am VERY dissatisfied.

Last weekend (3/28-30/08), I up-graded my '03 FLHTCUI OEM 5-speed tranny to an SE 6-speed that I bought from Republic HD (Stafford, Texas) for about $3K and change (including the side cover kit, misc. gaskets, oil, etc.). 200 mi. later, my brand new tranny is covered with oil!! Pulled fill tube, primary cover, tranny cover and starter to see where the oil was coming from. Guess! That stupid little chromed plate and gasket (35153-03 and 35152-03 respectively) that are supposed to seal the old speed sensor location on the case leaked like a sieve!! The screw was tight, but not sealing. This is a crappy solution by HD. Must have been the night-school engineering crowd. They should have designed a profiled cover like the speed sensor itself that fits down in the hole and uses an o-ring to provide a better oil seal. Not sure how to get all the oil off the transmission at this point. Called the Motor Company for their wisdom. They said something to the effect: smear RTV on both sides of the gasket!! WHAT CRAP!! But what did I expect - they designed this rinky-dink setup.

On the SE 6-speed available as a replacement unit, they use the same case as the original 5-speed tranny. Therefore, the 6-speed transmission case has the configuration (with old position speed sensor hole and tapped screw hole) as the 5-speed. However, in the 6-speed layout, the actual location for the speed sensor is on the top of the trap door. SE has cut a recessed profile that the speed sensor fits in. It is the same speed sensor that was used on the 5-speed. So I am NOT eliminating the speed sensor. The problem I am trying to fix is the original speed sensor location in the case. That is where this goofy design by HD of a gasket and plate is located. It does NOT seal. It came from HD, I unloaded it from the box, installed it on the bike, put the oil in it and then fired up the bike. Within 200 miles, about a third of the transmission oil had leaked out and all over the transmission. I am VERY pissed that I am having to engineer this problem because HD did such a crappy job of it.

I tried putting a neoprene gasket under the chromed plate. Did not like the look of things. Felt like it would probably leak (and I don't want to have to clean the transmission case off again!). So I went and got a hard rubber stopper (like for test tubes or flasks in chemistry class) and cut that approximately 1/4" above the point at which it was tight. Mounted the chromed plate with two rubber washers (about 1/8" thick total) under the plate on the screw end. Put some blue locktite on the screw and tightened down on the plate nice and snug. This should hold the stopper in-place nicely sealing the old speed sensor hole. I will keep a close eye on it for a few hundred miles until I feel confident this will work. I am also going to run a bit of a science project soaking (submerged) a stopper at room temp for a few months, and heating one in an oil bath for several hours at 300 degF to make sure the rubber will stand up.

This has been a particularly troubling experience for me with the Motor Company and Republic HD (Stafford, TX). I have spent over US$3K up-grading the OEM 5-speed to the SE 6-speed. When I ran into this challenge, I got a trivial suggestion to coat the gasket with RTV and reinstall it from both HD and Republic. This is NOT a good solution.

As I said above, the ideal solution, as far as I am concerned, would be for HD to design a plate with a profile that fits in the speed sensor hole and seals with an o-ring (like the speed sensor!). My little "garage engineering" effort was as close as I can get to this idea (no lathe, welding equipment, CNC miller, etc.).

I would have assumed that the dealership I bought the SE 6-speed from (Republic) would have gotten concerned when I told them that my brand-new tranny was leaking, and ask me to bring the bike to them so they could look at the problem. Well, that did NOT happen! Instead, I had to buy new gaskets (primary cover, oil fill tube, trannny cover) for about US$42 to put the bike back together after inspecting it for the source of the original oil leak problem. I also bought a NEW speed sensor (US$50+) thinking I could install it in the old hole, but when I measured the clearance in the hole and the length of the speed sensor, I realised it would not fit. I HOPE the dealership will take back the new, UNUSED speed sensor and credit my account at least. We'll see. (NOPE - they do not take back electrical stuff once it is sold - they say they have not way of testing whether the part is any good - in this case, I NEVER USED IT, JUST OPENED THE BAG SO I COULD MEASURE THE LENGTH OF THE SPEED SENSOR).

There are 4-5 HD dealerships here in the Houston area, but Republic is the closest. From now on, I will just ride a little further for the stuff I need. That is fixin' to be a bunch of stuff since I am just about to rebuild my '91 FXDB-S. This project will include a new 6-speed tranny. Guess where I am NOT gonna get a transmission from? Won’t even be a HD product!

At this point, if I had it to do again, I would spend the extra money and buy the Baker DD6. This is a pretty damning testimonial from a diehard Harley owner/operator rider/fixer.

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I would do the same as you with the Baker trans. It's a better unit and built by people that care.JMHO