Originally Posted by C10 - C90 Bill
...tell me more about the "Crash Box" 4-Speed.

Bill
Transmission with no synchronizers which was used before the SM420 came out in about 1948.

"Crash Box" is a term that could be applied to any transmission without synchronizers

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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