1941 trans case

[Steve Little]

Hi. I have a trans case that has the brass 5th mount/outrigger and a date plate E 0 May 1940.
On the verticle rib that the trans adjuster is tapped into, there is a factory stamped number 41 with serrifs.
Below this is a S with serrifs.
Is this to denote a 1941 gearbox setup for Sidecar?

Also... next to the date plate is a large (5/16") stamp. This has been stamped into the case after pouring. Does anyone know the meaning of this 1.
Suggestion...I saw a right engine case going through on ebay recently and someone posted if the linebore started with a 1 it was 1200cc if it started with a 2 it was 1000cc. Wonder if this follows on the trans cases.
Regards Steve

[Sargehere]

The letter the factory used on the 'reverse' trans tops, was a serifed "R" right on top of the drum detent, on the 3+Reverse trannies, and a "3" on the factory 3-speeds. You remember that there was a run of the last small (8-inch) flywheel 61 cubic engine cases (1936-40) that had "40E" for the beginning of their line bore numbers just about the time yours was being made. Apparently to insure that they didn't get mixed in during engine assembly with the '41 & later large-flywheel cases then just coming into existence at the factory. Your "1" might mean something, or it might mean nothing at all. I know of no other instances where the factory even utilized an oversized die stamp. Could be something an owner put on in the 70 years intervening.

[Speeding Big Twin]

Steve, a couple of guys have reported different letters or numbers stamped near the adjuster hole but I haven’t found a confirmed explanation for them. One person said they may have been stamped by an inspector at the Harley factory.

Regarding the 1 near the date code plate, on some BT trans cases you’ll find it accompanied by a capital E, sometimes you'll find a lone 2 and other times you'll find 2E (shown below) but I don’t know what any of those characters represent:



It's interesting to note in the examples I have so far that the E, accompanied by either 2 or 1, has only appeared on cases with date codes of September 1949 or later. But I have no idea what, if anything, is indicated by the addition of the E. And the E continued to appear on some cases with date codes from the late-50s and early-60s.

The line-bore code numbers were introduced for 1948 and usually worked as follows: 1 indicated 1200cc OHV; and 2 indicated 1000cc OHV. However, I’ve also found the exact opposite occurring for 1948, 49, 51 and 52. Palmer’s military book includes mention of the 1949 code being an enigma but I’ve seen it get stranger than that at times, with code number 3 appearing on some 1950s Panheads even though 3 usually indicated 750cc SV (1948 or later G-series and W-series). And I’ve also found code numbers 2 and 3 on some lightweight models. Eric

[46EL]

I just found Trans Case with a "G 0" Date Code. The trans adjuster hole has a "1" just above the hole at about 10 o'clock and an "H" a half inch above that. It also has the larger number 1 stamped to ther right of the Date Code Plate. My question is how can I tell if this case I have is 1940 or 1950? Thanks!

[cdndewey]

My C 9 case has a 2 stamped in it and my 8 60 case has a 1 E stamped in it. There's no doubt about the 8 60 as it came from my low numbered 62 FL, but the C 9 came from my basket 47 EL. Any ideas as to March 49 or 59?

I'll have a look at my buddys 47 FL this week as he has it apart restoring it. He's the second owner of it and I'm quite sure it is still the original as it was last plated in 54. It grew up in a remote area where we live....logging roads, dirt roads, goat trails...very few paved roads then.

[46EL]

Whether it is 49 or 59 would be easy to tell as the 59 Case should have never been drilled for the breather. The little boss should be there I believe but it should be undriilled. I also have a 1939 Case with an A-9 Date Code with a large 2 next to the Date Code. One the vertical boss there is a straight back 9, below that an "F" stamped at a 45 degree angle and a "0" stamped sideways??? Jp.

[Speeding Big Twin]

46EL and cdndewey, so far my examples show the BT trans case date code for 1938–49 consisted of a letter-number format. But it seems that codes for the 1950s and 60s BT trans cases involved numbers only, although the numeric format didn’t always follow exactly the same pattern, with sometimes only one character representing the year but on other occasions the year was indicated by two characters. Anyway, a date code of G 0 would indicate July 1940 casting.

Date code C 9 could indicate either March 1939 or March 1949. If it was March 39 the case may have a vent screw but there may not be a boss for it, with the area for the vent screw just machined flat instead. If it was March 49 it would have the boss and it would be drilled and threaded.

The case below has date code K 5 (November 1945) and you’ll notice the two areas I’ve marked with red crosses are rounded. Apparently they were cast rounded and left that way until about late-1946. But from then on those areas were flattened, either by machining or design.



However, sometimes you’ll find early cases which have had those two areas flattened at a later date, presumably by owners/others so there’s something else to check. Have a look at the insert for the mounting bolt on the underside of the case to the right-hand side. It seems the insert was bronze until around 1943-44 before being changed to steel.

46EL, I have an example of the 0 stamped sideways but I don't know what is indicated by it. It’s on a case with date code I 0 (September 1940) and I’ve posted it below. You’ll notice number 1 stamped nearby which sounds similar to the 1 on your G 0 case but I can’t explain what the 1 represents. Eric

[46EL]

1) I have an E-4 (1944?) Case that has the two milled flats. Most probably 44 unless someone took an undrilled 54 Vent case and drilled it? Correct?
2) I also have an A-9 Case that I always thought it was 39 and has unmilled ROUNDED cover studd bosses. I noticed that the Vent area had been milled/machined flat and THOUGHT it was done privately and not by HD? Are all 39 cases like that?
3) I still have my G-0 and i'm still confused. I thought it was 1940 but the flats are milled? But a January 50 case would be 1-50??

[cdndewey]

46 EL my case is a 49.
Speeding BT, where your 1 and 0 are my trans has a 40 and an F.

[Speeding Big Twin]

46EL
1. E-4 indicates May 1944 casting. I think the two bosses for the shifter cover screws were first flattened by the Harley factory about late-1946 to accommodate the gear shifter lever which was repositioned down, as opposed to up, for 1947-later models. As I mentioned in my previous post, sometimes you’ll find early cases which have had those two areas flattened at a later date, presumably by owners/others. So I’d suggest that is what happened with your E-4 case.

I don’t know if any cases have 1954 date codes. I have examples for 1950–51, 53 and 58–59 but one thing remains unexplained and that is the 3 3 code. Usually it would indicate March 1953 but trans cases on some bikes as late as 1956 models, unaltered from original, have been found with that code and no-one has figured out why that happened.

2. A-9 could indicate either January 1939 or January 1949. But yours sounds like 39 because it has rounded cover screw bosses and also because the vent area has been milled/machined flat. However, not all cases cast in 39 lack the vent screw boss. It seems the factory machined the vent screw area flat on some cases cast in 1939 but the one below appears to have the boss and it’s the earliest example I have of that. You can see the cover screw bosses are rounded so J 9 in this instance indicates October 39 casting but that particular case would probably have been for a 1940 or later model bike:





3. As I mentioned earlier, date code G 0 would indicate July 1940 casting. If a case was cast in July 1950 then I'd expect to see 7 0. Regarding January 1950 codes, I have two examples and both feature 1 0, not 1-50. I also have examples of 3 0, 6 0, 8 0, 9 0, 10 0 (shown above at post #3) and 11 0. However, sometimes you will indeed find two characters representing the year and the earliest example I know of is 2 58. Some later examples also have two characters for the year but some only have one.

So if your G 0 case has flattened cover screw bosses then I’d say that was done at a later date and not done as standard. They were only flattened as standard at the factory for about late-1946 and later. And did you check the insert for the mounting bolt on the underside of your G 0 case? I would expect it to be bronze. But the insert for your E-4 case may be steel. Eric

[Speeding Big Twin]

Quote from cdndewey: ‘Speeding BT, where your 1 and 0 are my trans has a 40 and an F.’

Cheers, cdndewey. I’ve seen an F before, and some other characters, but I don’t recall hearing about a 40 until yours. And I haven’t got a real explanation for any of them yet. Eric

[Hack]

I have a trans Dated L 9 with a milled&drilled vent boss a lonely 1 to the right. The adjuster boss is stamped with the mystery 40 quite clearly but with a T above it and a sideways F that is at the edge. I also have a 56-64 type undrilled boss box with the 3 3 date code and 2 E. Fun stuff, wish I could figure it out, and the Guide light codes too. Maybe I think too much.
My first post here so please excuse me if it is fouled up or the pictures don't appear.

[Speeding Big Twin]

Hack, all your photos look good on my screen. I’ve seen the 3 3 code mentioned on other forums too but no-one knows for sure why so many cases have it. And sometimes you’ll find 1 E there also:



L 9 on your other trans could indicate December 1939 or November 1949 (the letter I was skipped for 48–49). And I’d expect both to have a drilled and threaded vent screw boss. If the two shifter cover screw bosses are still rounded then that would indicate 39, as opposed to 49, but if they are flattened then the case could be either. Check the insert for the mounting bolt underneath: bronze indicates 39; steel indicates 49.

Something else intriguing is that the BT trans code isn’t always echoed by the 45” Flathead code. My examples so far indicate the BT trans changed from letter-number to numbers-only as early as January 1950, although I won’t be surprised if both formats were used for December 1949 because I’ve seen that happen with some engine parts. But it seems the 45” trans used a letter to indicate the month into at least 1953 as per the photo below which is the clearest, although not the latest, example I have for that year. You’ll also notice two numbers for the year and that happened with the 45” trans as early as 51, whereas the earliest example I have of a BT trans case with two numbers for the year is 58.



You mentioned Guide light codes. What are they? Eric

[Jerry Wieland]

46El If your tranny is a 1940 it will have a cast in bronze threaded insert for the 5th bolt and if it is 1950 it will be pinned steel insert in addition to what others have added.

Jerry

[rudy]

one more to look at