All MB auto trannies in 1970 were 4spds even the 6.3. The 3.5 v8 came out in 71 but still was a 4 spd. With the 1972 4.5 the 3 spd came out.

None of these were overdrives. All had final drive ratios of 1 to 1. The first overdrive auto trans was the 722.5 trans used in 300SLs 129 body. I would say around 1990. The 722.5 was similar to the 722.3 which started in 1981.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician