Harley tranny crack/weld, rebuild, project #2

[hooda]

Hooda's Project #2

So, this started out as a run of the mill build on a '76 vintage Harley 4 speed tranny. That was until I forgot the assembly sequence, one that I had done dozens of times over the years, but not for the last 6 years or so. In my infinite wisdom, I got it stuck in my head that an extra washer just HAD to fit into the countershaft assembly, in spite of the fact that it was proving to be a mechanical impossibility. Rather than wait and go toone of the shops I go to for parts and ask, I decided that the case must have gotten "bent", so I set up some wood blocks, got out the 5 pound lead hammer, and proceeded to "straighten it". The case survived 5 solid blows until it not only didn't straighten, but instead cracked neatly down the side.



The crack starts on top to the left of the small hole, and snakes it's way down and to the right. Here's a top view



And an inside view



Next post will show the welds, but it's lites out for now..

[hooda]

As mentioned above, I was trying to fit a countershaft assembly shown here



into the case. Here, I'm measuring the length of the assembly. Tha mistake came by the face that there's loose needle bearings in either end, with counterbores of differing depths, and 3 different thrust washers that go into the ends. 2 of the same in one end, one of those and one of varying thicknesses on the other end. I was going under the assumption thet a fourth washer of the first type went on before the variable thickness washer, and trying to "adjust the case accordingly", even with a factory service manual vaguely telling me different. My mistake, which I didn't figure out til the damage was done. I guess that I post these type of mistakes (on an HD forum, too), hoping to educate my peers, rather than have them do the same.
Here's where the variable thickness washer rides. Reason for the variable thickness is to set endplay. The basic design of this tranny dates back to 1936, essentially UNCHANGED until 1978-1/2, when the switch from loose needle bearings to inferior torrington-style bearings was made.



Below is a pic of the washer in question.

[DaveO]

I have the OEM shop manual for my car and have been staring at it for 15 years- it's very badly written, so I know what you mean about vague manuals. I notice the crack runs through a threaded bolt hole- do you run the danger of weld heat warping the metal slightly, and skewing those threads or any gasket mating surfaces?

[hooda]

I have the OEM shop manual for my car and have been staring at it for 15 years- it's very badly written, so I know what you mean about vague manuals. I notice the crack runs through a threaded bolt hole- do you run the danger of weld heat warping the metal slightly, and skewing those threads or any gasket mating surfaces?

Funny you should ask. I had to re-drill and tap 2 holes. Fortunately, they were non-critical, both in location, and function. LOTS of hand-filing to work around press-fit studs and screw-ins that may as well have been press fit. Due to the wide-open nature of this tranny, I was able to successfully get everything straight/true/flat enough for it to go back together with no issues whatsoever. Had this been a more modern 5, 6, or 7 speed (yes, there is actually a freaking 7 speed available nowadays!) I have doubts as to whether this type of repair would have been possible to do this way. Possible yes, but it would have required much more precision, more disassembly, and a bridgeport mill to get things beck in line.

[67cudafb]

Memory is the first thing to go, mine left and I am still looking for it. What was I saying? Looks like a whole lot of work to repair, nice job though. My concern would be that looks like high stress area with the gears pushing against each other. I would not dump clutch it could be ugly.

[Trip59]

Did you do anything special to prep before welding? I've got my 59 ironhead sitting in crates till I get geared up to repair the cases (also waiting till I have a mill in the shop...) but old, grease soaked castings give me a bit of pause.

[hooda]

Did you do anything special to prep before welding? I've got my 59 ironhead sitting in crates till I get geared up to repair the cases (also waiting till I have a mill in the shop...) but old, grease soaked castings give me a bit of pause.

I was fortunate enough to have this happen while the cases were clean enough to eat off of, when I reassemble a rebuilt part, it's surgically clean, but to be safe, I cleaned everything with chlorinated brake cleaner, followed by acetone, followed by hot, soapy, then hot clear water. (remember the phosgene warning). I was limited by accesibility to form any deep vee's or anything, so I made sure to have enough amps to get good penetration.

[hooda]

Here's some pics of the actual weld, and the finish work I had to do to get this thing ready for assembly.







Out of time. I will post pics of the completed tranny as soon as I can find them!

[sportbike]

Did you just throw a weld on the surface of the case? If so, I'm not so sure that is going to survive the vibration of a Shovelhead :-)

[jerky]

man that was one nasty crack. like sportbike said, i hope it holds up. how much more time did you spend fixing the "bent" casae?

[hooda]

man that was one nasty crack. like sportbike said, i hope it holds up. how much more time did you spend fixing the "bent" casae?

My STUPIDITY, all said and told, cost me a total of about 7-8 hours, if you count the time spent inventing new swear-words to express my frustration with