Automaticc trans.?
Drifting
Joined: May 2023
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From: Sierra Vista, AZ
Not a powerglide. It's a 300, used in Buick, Olds, Pontiac in the mid 60s. Earlier versions in Buicks and Oldsmobiles had the switch pitch torque converter
It's kind of a powerglide built like a TH350. Has a clutch for reverse, instead of a band.
used from 1964 till around 1969?
It's kind of a powerglide built like a TH350. Has a clutch for reverse, instead of a band.
used from 1964 till around 1969?
Last edited by jforb; Jul 18, 2025 at 11:32 AM.
Drifting
Joined: Sep 2004
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That is a Super Turbine 300 used in Buick, Olds, Pontiac back in the 60's. A 2 speed similar to the Alum PG. L-R Clutch, Hi-Direct Clutch and a Low band. Friction plates, Lo band and some of the bolts interchange with the PG but none of the hard parts do. And yes, early models used a VP, variable pitch torque converter activated with a switch on the front pump. They like the PG were dependable old 2 speed units.
The one in the pic is a non VP unit. You can tell by the splines on the pump stator and input shaft.
The one in the pic is a non VP unit. You can tell by the splines on the pump stator and input shaft.
Last edited by J.Moore; Jul 18, 2025 at 11:46 AM.
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That is a Super Turbine 300 used in Buick, Olds, Pontiac back in the 60's. A 2 speed similar to the Alum PG. L-R Clutch, Hi-Direct Clutch and a Low band. Friction plates, Lo band and some of the bolts interchange with the PG but none of the hard parts do. And yes, early models used a VP, variable pitch torque converter activated with a switch on the front pump. They like the PG were dependable old 2 speed units.
The one in the pic is a non VP unit. You can tell by the splines on the pump stator and input shaft.
The one in the pic is a non VP unit. You can tell by the splines on the pump stator and input shaft.
The ST-300 shares no parts with the aluminum Powerglide and doesn't have the Powerglide characteristic front pump whine.
Dan
Drifting
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This transmission was designed and built by Buick to replace its Dynaflow and Dual Path (used in the Skylark) and to replace Olds and Pontiacs use of the Roto-Hydra-Matic a.k.a. Slim Jim. It was the first of a series of new Automatics Buick worked on with Hydra-Matic division engineers, as it was followed by the ST-400 (Turbo Hydra-Matic) and the Turbo Hydra-Matic 350 both based on the ST-300 basic operation.
The ST-300 shares no parts with the aluminum Powerglide and doesn't have the Powerglide characteristic front pump whine.
Dan
The ST-300 shares no parts with the aluminum Powerglide and doesn't have the Powerglide characteristic front pump whine.
Dan
I rebuilt dozens of both units from the early 70's up till about 1980's when less and less of those cars were on the road. The noise was the planetary / ring gear whine. A well known noise and complaint from customers back in those days. The 300 had the same style planetary/ring gear but not interchangeable and the whine but not as noticeable as in the PG.
The 350 and 400 were 3 speed units and were totally different design. The 300 was similar to PG family with 2 friction sets and a low band and planetary / ring gear design.
The gear type front pumps in both the ST300 and Alum PG were very durable and very seldom were a problem unless the gears and pump body picked up trash (metal) from an internal part failure.
Last edited by J.Moore; Jul 18, 2025 at 04:41 PM.
Drifting
Joined: May 2023
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From: Sierra Vista, AZ
The similarity to the 350 is not in the gear train, but in the way the transmission was built...lot of differences from the PG, lots of similarities between the 300 and 350. Pump, modulator, reverse clutch, extension housing, shift linkage, cooler lines, etc all previewed the 350 five years before it appeared.
Drifting
Joined: Sep 2004
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The 300 and Alum PG were very similar although the only parts used in both were the 2 friction clutch sets and the low band. The 350 and 400 both 3 speed units totally different design only shared the vac modulator as common parts. The TH400 was the HD version used in many 4x4's and some performance cars usually behind big blocks but not always and HD trucks although the 400 was probably an option on many of the vehicles.
The 350 and 300 used the same vac modulator and rev friction plates. Also the Alum PG used the same rev frictions as the 300 and 350. The Alum PG used a different screw-in type Modulator. The later 4L60 and 4L60E used similar Rev friction plates but were about .025 thinner. You could mix and match the 4L60 with the ST300/PG Rev plates for a different clutch pack clearance if desired.
The 350 and 300 used the same vac modulator and rev friction plates. Also the Alum PG used the same rev frictions as the 300 and 350. The Alum PG used a different screw-in type Modulator. The later 4L60 and 4L60E used similar Rev friction plates but were about .025 thinner. You could mix and match the 4L60 with the ST300/PG Rev plates for a different clutch pack clearance if desired.
Last edited by J.Moore; Jul 18, 2025 at 05:05 PM.
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Ok. I know when I don't know. Thanks for the reminder and re-education. I was speaking far more generally than you fellas.
Dan
Dan
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