1934 Pontiac Transmission Question

[Dave Gelinas (XP-300)]

I'm aware that in 1935 Pontiac went to a synchromesh transmission.

Prior to that did the Pontiac transmission require double clutching?

 

If so, what is required to upshift 1st 2nd and 3rd, and what is required to downshift 3rd to 2nd to 1st.

Is down shifting similar to a Model A?

 

Thank you all in advance for your help, suggestions, and tips.

 

Edited November 6, 2023 by Dave Gelinas (XP-300) (see edit history)

[Bloo]

1 hour ago, Dave Gelinas (XP-300) said:

I'm aware that in 1935 Pontiac went to a synchromesh transmission.

Prior to that did the Pontiac transmission require double clutching?

 

Pontiac's transmission change was in mid year 1935. The whole story is a bit convoluted.

 

In 1932, Pontiac V8 and Six had a transmission of the family generally associated with the Buick 40 series. I'm not sure if Buick was even using this yet in 1932, but by 1935 Buick in Flint was the main if not the only source.

 

For 1933 the new Pontiac Straight Eights used a transmission of the same family as the Chevrolet Master/Eagle/etc. (not including Chevrolet Standard) was used instead. As far as I know all of these were synchromesh. It allegedly wasn't very good synchromesh. You might have to double clutch. This continued when the new Pontiac Sixes were added to the line for the 1935 model year.

 

In mid year 1935, there was a strike at Chevrolet's Toledo plant, the source of Pontiac's Chevrolet-based transmissions. Chevrolet bought transmissions from Borg Warner for part of the year. Pontiac switched back to the Flint built transmission family that we usually associate with the Buick 40. Apparently that change had been planned for 1936, but due to the lack of transmissions coming from Toledo, the change was made in mid year 1935 instead. Late in 1935 a few more of Pontiac's cheapest model were built with the Chevrolet-based transmission. In 1936, all Pontiac transmissions were the Buick 40 type.

 

It is said in various internet writeups that there were some non-synchromesh transmissions, or that Pontiac "switched" to synchromesh in 1935, or sometimes mid 1935, or that Pontiac's cheapest model had no synchromesh. Another thing oft repeated is that Pontiac went to a "fully synchronized" transmission with a synchronized first gear in mid 1935. I don't believe any of that is true, and nothing in my parts books backs any of those ideas up.

 

All of the transmissions I have described above are synchronized on second and third. Pontiac did not synchronize first gear until sometime in the 1960s.

 

Edited November 6, 2023 by Bloo (see edit history)

[Dave Gelinas (XP-300)]

19 hours ago, Bloo said:

 

 

All of the transmissions I have described above are synchronized on second and third. Pontiac did not synchronize first gear until sometime in the 1960s.

 

So, is the 1934 a synchronized transmission on second to third and third to second? 

[Bloo]

Correct, as far as I know, and my 1937 parts book seems to back that up. Also synchronized first to second, since the synchronizers are on second and third, but not first. It's the same setup as most if not all other synchromesh of the period.

 

The internals of this Chevrolet-based transmission should be mostly the same as a large series Chevrolet of the same year. The synchros required internal clearances to be set with some selectable thickness parts, probably snap rings but I don't recall exactly. It is my understanding that even when set up correctly you can't expect these synchros to just work flawlessly like you can in Pontiac's Buick 40 based transmission, or in the new Chevrolet transmission that replaced this type in Chevrolets for 1937 onward. Your mileage may vary.

 

It might be useful to have the oil viscosity just right to make timing the shifts easy. You might need to do some double clutching. These are things you would normally be thinking about when you have an unsynchronized transmission.

[Dave Gelinas (XP-300)]

On 11/6/2023 at 4:23 PM, Bloo said:

Correct, as far as I know, and my 1937 parts book seems to back that up. Also synchronized first to second, since the synchronizers are on second and third, but not first. It's the same setup as most if not all other synchromesh of the period.

 

The internals of this Chevrolet-based transmission should be mostly the same as a large series Chevrolet of the same year. 

Were Chevrolet transmissions used on the 1934 Pontiac 8’s?

[Bloo]

Yes, more or less.

 

I highly doubt it would directly bolt into a Chevrolet, but I am not completely sure it won't. The internals would be about the same as the Chevrolet Master's transmission from the same year. I think most of the internal parts would be exactly the same.

 

 

Edited November 10, 2023 by Bloo (see edit history)