Hi
I need some help to identify this speedometer drive. I thought it was 41-48 but the 41-48 has a different cut on the gear and they look a little longer. I have to put the car on the lift and take it out for dimensions, I will try and do that in the next couple of days. any thoughts??? I need one.
Thanks Dale

What did you get it out of?

I didn't think 41-48 had the teeth leaning left. Maybe some kind of a 4 speed truck?

Well if I knew what it came out of I would know what it's for :-) I have know idea whats it's out of. It's now in an overdrive, I drilled and tapped the OD and put the drive gear in as it was a perfect fit, looking for another one so I can modify it for something else.
Dale

Do you want to buy a 41-48 Speedometer gear? I should have one. If I do it will be around $40 which includes shipping.

I will be out of town until Thursday evening.

Thanks, Mike

ebay Speedometer Gear

41-48 looks longer, I need one exactly like the photo in the first post.
Dale

Never mind longer, the teeth are leaning the wrong way on the 41-48 gear. That means that the matching gear must also have the teeth leaning the opposite way. It also means that the rotation is reversed.

I have been searching for quite a while now for similar gears to adapt to my 1936 Pontiac in about a 2.8-ish ratio (5-14?).

The trouble is, Chevrolet moved the drive gear from below the shaft, to above the shaft in about 1935 or 36, and that requires an opposite lean on the teeth to get the correct rotation. Before that, the gear was on a long shaft, and not supported solely by the "bullet" like yours is. The implication is that MOST Chevrolet gears will not work for you (or me) because the rotation is wrong, never mind how long it is.

Pontiac moved the gear above the shaft in 1937, so anything Pontiac 1937 or later wont work. The same is (probably) true for Buick back to the mid 30s at least.

Late 1935-1936 Pontiac gears have the same lean to the teeth as yours, and that may even be what they are. I will try to get some pictures. They were originally available in 4-14, 4-13, and 4-12, with 4-13 being by far the most common.

The only possibilities in Chevrolet I am aware of (so far, and I'm not even sure) with the correct "lean" are the SM420 truck transmission, and the non-synchronized truck 4 speed that preceded it.

I think the SM420 bullet is long like the 41-48 bullet pictured. I have not been able to find what the ones for the non-synchronized 4-speed look like, or which way they turn.

Maybe Gene knows something. I have been meaning to ask, but haven't got around to it.

What tooth count do you have, and what tooth count do you need? (On the worm gear, count tooth ends around the circumference.)

The drive gear for the SM420 truck transmission looks promising
Thank you!
Dale

The Pontiac ones look like this:



What are the tooth counts on the ones you have? I would also really like to know what they are, as they don't appear to be Pontiac (no shaft tip), but would probably adapt.

Pontiac 34-35-36 Transmission

Just wondering,

Mike

mine is 12 tooth, I know a little more about it, it is a modified drive from a SM420... I think?

Just;looked at your last photo, looks like 12 tooth if I counted right. sending you a PM
Dale

Mike what ifs the tooth count? apparently form what I have seen there is a 12, 12 and 20 maybe more, this looks like a 12 or 13.
Dale

That could be 1935 Pontiac, as he says. If so the gear type is probably identical to 1935 Chevrolet Master. Teeth lean the correct way, gear has the long shaft that supports it from both sides, (rather than the gear type in the original post).

I think the Hollander interchange shown must be for the transmission case, not the transmission. The tail casting would be different if it were 1936 Chevrolet. The speedometer gear would be above the u-joint, and the teeth would lean the wrong way.

1936 Pontiac, and late 1935 use Buick-style transmissions, nothing like the auction. Rear casting (and speedo gears) on those are unique to Pontiac as far as I know, because they connect a Chevrolet-style torque tube to the Buick-style transmission.

My picture was 1936 Pontiac. I would expect 1935-early Pontiac to be identical to 1935 Chevrolet Master, because both transmission and torque tube are the Chevrolet design. There could be differences at the front of the transmission.

Hi I tried several times to send you a PM and it said user not found???
Dale

I know this is an old post, but does anyone have this part? I'm looking for one for my 1951 3100, but it looks identical to the one that Mike Buller posted was for '41-'48.

You'll need to put an ad in the Parts Wanted forum. Those with parts to sell monitor it.