Project 1 From Hooda Tranny case repair (FOR 1st 2013)

[hooda]

So, I'm active on another forum, where I offer the service of building/rebuilding Harley-Davidson Transmissions. I had a guy order a new 5 speed transmission for his 1971 Harley (customized). The old HD's used basically the same 4 speed gearbox from 1936 to 1985, with surprisingly few major changes over 49 YEARS!!!, except a transformed top cover in 1981 or so, which was a complete blow. Anyway, one of the best changes a guy can do to one of these old beasts is to upgrade to a 5 speed tranny. Problem is, it's NOT a bolt-in affair. But they make a special case that allows a 5 speed gearset in a 4 speed case, aptly called a 5-in-a-4. So, I bought a new case and it arrived today, in the crisp, clean box, sealed and marked in Usan, Korea. I unpacked it, and it looks great, except for the fact that the mounting studs on the bottom are NOT supposed to be drilled through the case!! Luckily, I have a 250EX, which will make quick work of sealing these spots up. Photos and more details will be posted when I get back to my shop at the end of the week.

[zoama]

So, I'm active on another forum, where I offer the service of building/rebuilding Harley-Davidson Transmissions. I had a guy order a new 5 speed transmission for his 1971 Harley (customized). The old HD's used basically the same 4 speed gearbox from 1936 to 1985, with surprisingly few major changes over 49 YEARS!!!, except a transformed top cover in 1981 or so, which was a complete blow. Anyway, one of the best changes a guy can do to one of these old beasts is to upgrade to a 5 speed tranny. Problem is, it's NOT a bolt-in affair. But they make a special case that allows a 5 speed gearset in a 4 speed case, aptly called a 5-in-a-4. So, I bought a new case and it arrived today, in the crisp, clean box, sealed and marked in Usan, Korea. I unpacked it, and it looks great, except for the fact that the mounting studs on the bottom are NOT supposed to be drilled through the case!! Luckily, I have a 250EX, which will make quick work of sealing these spots up. Photos and more details will be posted when I get back to my shop at the end of the week.

Are you sure it's not designed that way... does the stud have a shoulder on it ? How deep is the boss ?

[DVA]

So, I'm active on another forum, where I offer the service of building/rebuilding Harley-Davidson Transmissions. I had a guy order a new 5 speed transmission for his 1971 Harley (customized). The old HD's used basically the same 4 speed gearbox from 1936 to 1985, with surprisingly few major changes over 49 YEARS!!!, except a transformed top cover in 1981 or so, which was a complete blow. Anyway, one of the best changes a guy can do to one of these old beasts is to upgrade to a 5 speed tranny. Problem is, it's NOT a bolt-in affair. But they make a special case that allows a 5 speed gearset in a 4 speed case, aptly called a 5-in-a-4. So, I bought a new case and it arrived today, in the crisp, clean box, sealed and marked in Usan, Korea. I unpacked it, and it looks great, except for the fact that the mounting studs on the bottom are NOT supposed to be drilled through the case!! Luckily, I have a 250EX, which will make quick work of sealing these spots up. Photos and more details will be posted when I get back to my shop at the end of the week.

Drilled thrugh the case as in the case will not hold oil?

[cbmkr]

You are right those are supposed to be blind holes that should have been short bored and bottom tapped. Boring them fully into the case will make them leak with no way to get a good seal.

[agent4573]

Maybe they were just trying to keep the HD legacy of leaking like a stuck pig alive.

[Jason]

Any pictures or anything yet?

[Spike]

They can go either way. High quality transmissions will have blind tapped mounts, but cheaper ones will not.
studs are supposed to be used in those holes, not a bolt, and normally one would loctite or use Teflon tape on the stud bases.

[Spike]

... one of the best changes a guy can do to one of these old beasts is to upgrade to a 5 speed tranny. Problem is, it's NOT a bolt-in affair. But they make a special case that allows a 5 speed gearset in a 4 speed case, aptly called a 5-in-a-4...

Hey Hooda, i've got a part kit you might love, then. and it *is* a bolt in affair. It's a 6-speed conversion for the shovels.

Spike Customs 4-to 6-SPEED CONVERSION DRIVELINE KIT for SHOVELHEAD

It updates the bike with a brand new (new style) 6 speed transmission, a new style Primo/Rivera clutch and 3" open belt drive, as well as updating to a new style starter. It includes the modified transmission plate to make it all be a bolt on project! I've had a couple of people put them on their shovels, and i'm building one for me right now and i'm going to throw one in it, too.

when you hook the old shovel up to a 6 speed, it makes it like a brand new bike again, and doesn't have a problem keeping up with these new yuppie harleys and freeway riding.
If you do transmissions then i thought you might like it!

[hooda]

Hey Hooda, i've got a part kit you might love, then. and it *is* a bolt in affair. It's a 6-speed conversion for the shovels.

Spike Customs 4-to 6-SPEED CONVERSION DRIVELINE KIT for SHOVELHEAD

It updates the bike with a brand new (new style) 6 speed transmission, a new style Primo/Rivera clutch and 3" open belt drive, as well as updating to a new style starter. It includes the modified transmission plate to make it all be a bolt on project! I've had a couple of people put them on their shovels, and i'm building one for me right now and i'm going to throw one in it, too.

when you hook the old shovel up to a 6 speed, it makes it like a brand new bike again, and doesn't have a problem keeping up with these new yuppie harleys and freeway riding.
If you do transmissions then i thought you might like it!

Hey Spike, Thanks for the info, I'm aware of the kit, but the point here is for me to make MONEY custom building the transmissions to customer specs. With that kit, I might make a little on install with a local customer, but I'm in Minnesota, and my current customers are in Washington State, Nebraska, Texas, and Florida. Most of them know about the kit, and are also aware of the fact that they can get a 5/4 or 6/4 for less than I would charge, but I offer a superior product. I know you're intentions are good, and I thank you for that. Look at it as if you were building a Cobra replica (which is one of my life's goals) You can get on the net and order a 427 ford FE, ready to go, or call a guy like me to build you one on personal level, to your EXACT specs. Most of the people wanting work done by me KNOW me, and what I can do (If you look at some of the welds I've posted, and the flaming I got, it's obvious I'm not a pro welder), and I have a stellar reputation with the original 4 speeds, I'm expanding into 5/4's and 6/4's by request.

[hooda]

Howdy Folks! Below are some pics I took last night of the problem area. As you can see, there are 4 studs mounted outside the case to attach to a mounting plate. They SHOULD have been drilled and Blind-tapped (something I do to parts at my day job many times a week), to prevent transmission oil from seeping through. But that would have taken more time, and a little CNC savvy that the manufacturer opted out of. I've seen this before, and it doesn't matter what you do (thread tape, sealant, epoxy, etc) The vibrations of an old Harley WILL make an exposed hole like this leak eventually, usually sooner than later.







I tried using "paint" for the first time (in Everlast green) to highlight the trouble spots. The first pic is a bottom view. The 4 large (3/8-24) studs are the problem. On the more expensive ($550 vs $270) locally made case, these are NOT drilled through, but for the price difference I can do a lot of welding, if needed.

Now, The million dollar question. Do I leave the steel studs in place while welding as a "backer"? or do I remove them and go to it. The welds will need to be flush to the parent casting, and the end of the stud is about 1/4" below the surface, allowing plenty of room for filler material. For those not familiar with tapping on a CNC mill, like this was done on, the "easy way" to get a hole tapped is to simply drill the hole deeper than the needed thread depth by about the diameter of the hole, as a normal tap of this size would typically need to be tapped 1/4"-3/8" deeper to allow for the pointed end of the tap, and get to full threads. In a job like this, the way around that is to grind some of the end of the tap, or use a spiral-fluted tap to extract the chips being made, but doing so creates problems that can be dealt with, but it takes time. They opted NOT to take that time, So here we are.

What say you? Studs in, or studs out?

[Jason]

Welding with the stud in, would you be worried that the filler may get to the stud welding it into place?

[zoama]

I would leave the studs in since the aluminum won't bond to them. A bottoming tap is the proper way to thread close to the bottom of a hole. If the case is iron I'd leave them in and put a thin copper slug on the bottom of the stud
In MS Paint, use the shapes to highlight, such as a circle. I used Alt + print screen on the keyboard to capture the active window, In this case MS Paint, then select "paste" in ms paint to manipulate the image and saved as a jpeg. If you upload your image directly to the forum from your computer, it will be resized automaticly and show up as a thumbnail. When a page is full of full size pics it causes the page to load slow for those with slower connections and uses more bandwidth for those with caps. When you use thumbnails the user can decide whether to load them or not... not complaining, just offering a suggestion.

[Rambozo]

3/8"-24? That sounds like a bad plan all the way around. Fine thread in aluminum doesn't usually do well. The typical thing is to have 3/8"-16 on the aluminum side with 3/8"-24 for the nut. You could weld it up either way. If it really is fine thread I would drill it out to around 1/2" and weld it up solid. Then drill and tap for the new thread. I'm guessing that these studs are not removed much, and just the nuts are taken off for service work? For that I would be ok with a steel stud in aluminum. However, if the studs get pulled from time to time, I would want heli-coils installed so the stud doesn't ride on the aluminum. I would not use a steel stud as a backer as it could very well lock in there. If anything I would use a 5/16" round copper bar as a backer to help hold the proper depth. Then grind out a chamfer on the inside and weld it up. There are plenty of ways to correct this issue. Some don't even require welding. You will have to select the best method for the application.

[Tanh]

I'm with Rambozo on the fine thread detail. The suggestion of drilling it out to 1/2" is good but instead of filling and tapping, I suggest you use an ezlok. 1/2"x13 outer thread and 3/8"x24 internal. Your bolt/stud will have steel on steel contact while mating to coarse thread for aluminum. This method also allows for easier servicing and less chance of damage during multiple disassemblies.

We use this for fixturing in our shop. 5000lb steel fixtures can be held to AL tombstone pallets using this method. Here's a link.

http://www.catalogds.com/db/service?...roduct=319_624.

[Rambozo]

If you use a blind insert it will also correct the leakage issue. I remember some engine uses that as a plug in the end of a pressurized oil galley to provide a threaded hole to mount accessories on.

[hooda]

Thanks for the suggestions, but the studs are actually 3/8-16 on the case side and 3/8-24 on the mount-up side. The only time I've ever seen them pull out is if they're not properly tightened.

[jakeru]

Hooda - if the end of your stud is recessed, you shouldn't have much problem with "capping" the aluminum over it using TIG. If you want to try and save the finish of the stud (I'm guessing is zinc, cad or similar plated), I'd recommend establishing your arc on the aluminum parent metal off to the side of the hole (not directly on the end of the stud), then, after the puddle is established there, moving that puddle over into the middle over the end of the stud, while adding in filer rod as you go. Finally, before terminating the arc, you could move the puddle around in a circle along the circumference of the where the hole originally was, to ensure that there is no oxide inclusion, which could be weak, and potentially crack or leak.

If you moved the puddle right up against the back of the stud, I'd expect to see some torque required to break it free, from the puddle being adhered to the stud. A stainless bolt may be good to use as a backer (being more resistant to damage from the arc, and probably more reusable) than plated steel material.

I suppose you could even leave the studs installed (rather than removing them at all), however if the studs are intended to be removable, I'd tend to want to make sure removing them doesn't cause any problems, before assembling everything.

I've done this before when the threads were even protruding by a little bit from the surface of the aluminum hole (which FYI gets considerably trickier to pull off the more than the the threads protrude from the surface). Best of luck!

[Spike]

If you've got enough clearance between the gears and case, when I do that kind of plug fill, I will make a "cap" out of aluminum, bigger than the bolt hole you are trying to cover. Then weld it down over the bolt with the studs in (but no torque on the threads). This way you aren't welding right over the threads where you can melt them and booger them up, (or have molten aluminum wick down the threads) and the cap just needs to hold fluid out, not hold torque from the studs, so it doesn't have to be really thick.

[Spike]

And I completely understand about people wanting 4 speed cases over all the new design stuff. The conversions are only for a select few people. Aside from how much it costs, most people like their old bikes to look like their old bikes. they just want them a little better.
When I get down to the final build on my personal shovel, I may still just go with an old kicker Trans over the updated stuff.

[Jason]

personally I like the copper backing idea. I purchased some cheap 1 ft copper pipes that I flattened one end of to use as backing when I am MIG welding holes shut in body panels and such.