Quote:
55PackardGuy wrote:
This is a very interesting discovery! I have a technical question, though. Was the "torque converter lockout" of the Detroit Gear transmission an actual locking system with clutches, as the Twin Ultramatic?
If not, was the locking torque converter in the TU a big leap anticipated by Borg-Warner, and possibly a cause of their interest in the Ultramatic? To my knowledge, no locking torque converter automatic transmission was available again until Chrysler did it in 1979 or so.
Of course, today there's hardly an automatic transmission made without a locking torque converter. Gee, would that mean that Packard had it first by 14 or 15 years, and now it's the industry standard? Sounds like Packard.
As I read the notes at the bottom of the scan I posted, the DG works exactly like the original Ultramatic prior to the "Gear Start" of 54 and the TU of 55.
Operation as described by Langworth: "In the drive position, the gearbox provided two automatically shifted forward speeds, starting in second, or intermediate with torque multiplication assisted by the converter. For a third speed, the friction clutch was hydraulically engaged, the converter and planetary gears cut out after driveshaft speed and throttle opening were in correct configuration. Manual downshifting from top to second was possible at speeds lower than 50mph by flooring the accelerator, while the "low" position embodied manual gear hold for fast takeoffs or engine braking, during which torque was transmitted by the hydraulic converter and planetary gearset."
The transmission was air cooled and incorporated an anti-creep device that held pressure in the rear brakes. Stepping on the accelerator released the brake pressure. This anti-creep device was also used as the "hill holder" on manual shift Studebakers.
As I understand the Ultramatic, the only major difference between the earlier models, vs the gear start and TU is that, having observed that owners were starting in low to get off the line faster, then manually shifting into "drive". The gear start and TU automated that low/drive upshift. A feature that B-W could probably have incorporated into the DG as easily as Packard did with the Ultramatic.
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