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1964 THM/ST400 shift patterns


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I think I'm right that Cadillac and Buick used different shift patterns for the new-for-64 "400" transmission, but figured best to ask the folks who know.

 

Cadillac:  P R N DRIVE L

 

Buick: PARK R N D L

 

Did the 1964 Buick version utilize 3 speeds in the single D position? And did L keep it in low or allow a 1-2 shift?

 

Caddy version is straightforward enough, utilizing a "traditional" Cadillac 2 position DRIVE position. 1965 Buick and Chevrolet iterations added L2 position, and we know one way GM got Olds and Pontiac to buy in was retaining their beloved Super range (albeit as a 1-2 shift as opposed to HydraMatic's 1-2-3 shift).

 

Also wondering if THM/ST were designed with knowledge of the upcoming 1965 federal fleet standards?

 

 

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Flash obliterated anything above N in second picture. First picture is great.

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1964 Buick Wildcat;

1964 Buick Wildcat Sport Coupe 401-4 V-8 Super Turbine 400 (aut. 3) specs

 

Interior shot of 1964 Buick Wildcat;

21693740-1964-buick-wildcat-std.jpg

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Must have found a pic of a 65 Cad dash when I was looking last night as that 64 dash pic clearly shows "D L" and not "DRIVE L".

 

That answers part of my question, but how did the 1964 trans operate? 3 speeds in D? Was there an intermediate range in L or did the trans hold in first gear in L?

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22 hours ago, rocketraider said:

Must have found a pic of a 65 Cad dash when I was looking last night as that 64 dash pic clearly shows "D L" and not "DRIVE L".

 

That answers part of my question, but how did the 1964 trans operate? 3 speeds in D? Was there an intermediate range in L or did the trans hold in first gear in L?

My guess is that D = all three forward speeds and that L = first only. Remember Buick and some Chevrolets had D L2 L1, while on the same trans in Olds or Pontiac it was D S L when using 400 HydraMatic

Strange considering the original HydraMatic only had D & L, but then in 1952 HydraMatic division decided to control the transmission ( add a feature) by adding Dual range and since then continued with that.
The only way to know for sure is to find someone with that car, or try to find road test from magazines of that era.

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Posted (edited)

The problem is that we're all guessing. Does someone have a 1964 Riv owner's manual or Chassis Service Manual? The ST400/TH400 shifts through all three gears in "D". The 1964 ST400 uses a unique valve body and spacer plate that does not interchange with those of later years. I do not have any insight into how it shifts, however. Just don't read too much into what the shift quadrant says. In later years the D-L2-L1 and D-S-L cars have the same fluid flow diagrams inside the trans. The nomenclature was just marketing.

 

UPDATE:  I just found a reference that indicates that the "L" position on the shifter causes the ST400 to shift between first and second gears, so it sounds like the same as the "S" or "L2" position on later cars.

Edited by joe_padavano (see edit history)
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I had a 1964 Cad 60S with the new-for-1964 (but not all models) TH400.  L (low) range stayed in first, but could also serve as second above a threshold speed.  For example, on a steep downgrade, you could be in 3rd in D, pull the selector into L and lock it in 2nd for engine braking.  Below a threshold speed in L, the tranny would drop to 1st and stay there.  I used the car for some towing, and would start (as on a freeway on ramp) in D (1st), allow it to shift to 2nd (still in D), then pull the selector to L which would hold the car in 2nd until I was on the freeway and up to maybe 40-45, then move the selector to D to get 3rd.

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20 minutes ago, Grimy said:

I had a 1964 Cad 60S with the new-for-1964 (but not all models) TH400.  L (low) range stayed in first, but could also serve as second above a threshold speed.  For example, on a steep downgrade, you could be in 3rd in D, pull the selector into L and lock it in 2nd for engine braking.  Below a threshold speed in L, the tranny would drop to 1st and stay there.  I used the car for some towing, and would start (as on a freeway on ramp) in D (1st), allow it to shift to 2nd (still in D), then pull the selector to L which would hold the car in 2nd until I was on the freeway and up to maybe 40-45, then move the selector to D to get 3rd.

I think you've got the last piece of the puzzle that Rocketrader is looking for.

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On 5/25/2021 at 12:50 PM, joe_padavano said:

UPDATE:  I just found a reference that indicates that the "L" position on the shifter causes the ST400 to shift between first and second gears, so it sounds like the same as the "S" or "L2" position on later cars.

 

Nope.  Unless the Riv is different than an Electra.  As a wee lad of 16, I was very familiar with the operations of the transmission in my very first car, a 1964 Electra.  Describing the operation as such:  Place shift lever in "L" and it will hold first gear until you move the lever out of "L".  My method was to hold "L" until the car would no longer accelerate, slap to "D" and back to "L".  The transmission would respond with a very firm shift to 2nd gear, barking the rear tires on the Electra.  Unless you moved the shift lever, the transmission would hold first (or second) gear until moved to "D".

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Posted (edited)

     I've owned a '64 Riv. since it was new. Today it has over 300K on it. After yrs. of saving I bought it at 18yrs. old. Didn't take long to find out, by experimeting, the way the trans. worked. Being 18 it took a lot of grief & up until recently I would drag race & rat race with other foreign & american cars & know it's capabilities & short comings. Some of which have been taken care of by designing my own parts. 

    Put the trans. in "L" & you could hold it there, even if the engine was capable of doing 10K RPM's. Then shift to "D" & back to low again to hold 2nd. as long as you wanted then into "D". 

    In '65 Buick did two things. 1st, they redesigned the shifting pattern to read D-L2-L1. IF you held the shifter in L-1 when the engine got to 5500RPM's it would automatically shift into 2nd. gear with NO movement of the shift lever. This was done BECAUSE back in the day too many Buick's & Cad's came into the dealers with "Blown" engines on Monday mornings. This was because the 18yr. olds would take the parents car on Fri. Sat. night & have some "Fun".  They had to do something as this was causing GM big bucks for engine replacements & that was the fix.

    2nd. in comparison to the old "Dynaflow", which was extremely smooth because in "D" there was no gear shifting. It was a smooth as silk because of this. The only thing connecting the engine to the rear tires was fluid. Today most all the automatics try & emulate the ole "DynaFlow' for it's smoothness by staying in a higher gear than would normally be expected & because of this slipping of the torque converter would cause the trans. fluid temp. to rise out of site. That is NOT good for longevity. Also in "D" the old Dyna would not normally creep when your foot was off the gas pedal at a light mostly because it was also very ineficent.  Along comes the TH400 & it would creep at 4-8MPH with your foot off the brake at a light & was much more effient.  So the switch-pitch came in. The vehicle would go into "high" stall at a light, slip, with your foot on the brake or when you took off from the light or at 3/4 throttle so the car/trans. Still had ampile power to start moving. It also smoothed out the idle RPM's because of the higher stall & wouldn't creep as badly. Most of this was due to the kinda radical camshaft design used to make some power from the ole "Nail". 

    I remember my Dad & many older men of the time concidered the quality of an automoblie by how little or not at all that it would creep at a stoplight with your foot off the brake. The Dyna did it because as smooth as it was it was pretty inefient.

That's all for tonight.

 

Tom T.

Edited by telriv (see edit history)
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