The very,very early TG had the HR (hill retard) letters.This is also only shown in very early literature.It was changed to GR (grade retard)
so as not to confuse drivers into thinking that HR indicated "high range".....A logical thought as the transmission didn't actually up-shift.A HR car would be very rare.
The very early TG had some problems.After a first batch they were reworked to eleminate the problems.This resulted in them not being available in quanity until about Jan. of 1957.During this down time the GR apeared.
GR must never be used for forward movement, only for down hill braking.The use of it for starting off always meant failure.
The 1957 TG was not a good unit and the 1958 was worse.There were revisions made later to up date the forward, neutral and reverse cone clutches in the 1958 to the multiple disc clutches used from 1959-61.The 1959-61's were a decent transmission.There were no updates made for the 1957's....and if they weren't abused such as shifting from drive to reverse ,such as rocking back and forth when stuck in snow,or attempting to start in GR, they could give fair service.
Seeing that there is never a gear change once in drive range they will not be harmed by full throttle operation,etc.When floored the "variable pitch" feature of of the torque converter stator will allow the engine to speed-up and act as a passing gear under 55MPH - also will increase the torque multiplaction for more jump off the line.This is controlled by the carb. linkage rod-that runs down to the transmission.For it to operate correctly correct adjustment is necessary.
Most internal parts fit 1957 only.
