Transmission identy

[ldfly112]

I have purchased a couple panhead chopper rolling chassis one has a electric start transmission with a ratchet top There is a part number on bottom of the case #34709-78 is this a harley davidson part or could it be a aftermarket part

[Rubone]

That is the late '70s casting number on an H-D transmission for a rotary top trans.

[ldfly112]

Does that mean that the transmission tops are interchangable . I would like to install a hand/tank shift top on the tranny do you think it will bolt up OK Thanks for helping

[ldfly112]

My goal is to install this in a ridgid frame with elec. starter any advise of the parts I will need I prefer all oem harley parts

[dukekleman]

Rotary and ratchet topped 4 speed transmissions are not interchangeable. Very different bolt/Gasketing designs.

Duke

[Rubone]

Post a picture of your transmission. It will help with your questions.

[duffeycycles]

As Robbie & Dukeleman have posted,'78-'79,1980 -1986 was different case,bearing & gears.VTwin shows 34079-80 ratchet top conversion expensive & BACKORDERED.The rotary top replacement parts they currently sell actually work...not the older parts they used to sell.Buy a good condition ratchet top for your project & stay away from the rotary

[Speeding Big Twin]

I notice in another thread you mentioned having a hard time posting pictures and you’re receiving assistance with that but in the meantime here are two photos of a Harley case with casting number 34709 78 for comparison with what you have. Notice in the first photo there is also a small plate with what may be N27 on it and your case may have a similar marking underneath or on top but I don’t know what it indicates. Also notice this case has no casting date code but your case may have one? If so please let us know what it is.







Notice the front of the case has been machined to accommodate a speedo drive unit assembly but some of these cases were not machined. Has yours been machined or not?

In the area I blacked out is an additional original component identifying number, aka security code, aka supplemental number, aka anti-theft number. Your case may or may not have additional ID. If it does please let us know what letter or letters it begins with.






Next two photos are of a Harley case with casting number 34709 79. Notice the top of this case is different to the top of the previous case.
Eric

[ldfly112]

Thanks for showing the pics my case is the same as the first one shown but i cant find any casting numbers just the part number . just wondering if a tank shift top will bolt up to the top of that trans.

[ldfly112]

after looking again at the case the area that you blacked out has a number stamped Z1389 and on the bottom of my case under part number is also a 2 stamped in

[duffeycycles]

top pic is for ratchet top or hand shift..looks like -78 above,...this is a repop in my pic
next is 1980 FXWG case numbers

IMG_1336.JPG IMG_1335.JPG

[Speeding Big Twin]

Thanks for showing the pics my case is the same as the first one shown but i cant find any casting numbers just the part number . just wondering if a tank shift top will bolt up to the top of that trans.

You’re welcome. When you say you can’t find any casting numbers I imagine you mean you can’t find a casting date code. I’m not surprised though because some of those cases don’t have one as per the first case I posted above.

But you do indeed have a casting number and it is 34709 78. (It isn’t a part number.)

The lone 2 underneath is on many 70s and 80s trans cases and my best guess is an inspector marking. (Some 70s and 80s trans cases have a lone 1 or no lone marking.)

In Z1389 the letter suggests a 78 model and perhaps an early-78 or mid-78. For late-78 it seems the Z was finished and I think that’s when double letters may have first appeared. For example AA1234.

Yes a handshift lid will bolt on to your case.

You mentioned a couple of Panhead chopper rolling chassis. Do you mean you intend to use a Pan engine with that transmission?
Eric

[ldfly112]

Yes pan engine with electric start give me your thoughts

[jorrow]

I have a 65 tranny which is electric start and tank shift top I would sell. if you are interested PM me.

[Speeding Big Twin]

Yes pan engine with electric start give me your thoughts

I’m not sure if you mean you already have a Pan engine or if you have yet to buy one? What year Pan engine do you intend to use?

For 48–64 Pan engine sprocket shafts there was more than one type although I think they were the same length. For 65 Pans the length increased and so did the length of the trans mainshaft. The increases in length for 65 were partly due to the addition of an electric starter. Also originally fitted to 65 Pans were aluminium primary covers.

As of 70 Shovels there was another increase in the length of the engine sprocket shaft and the trans mainshaft increased in length at the same time.
Eric