The Datsun “B” Series Automatic Transmission

Datsun Automatic Transmission 3N71B 1971 – 1983 Datsun 240z 260z 280z 280ZX

The Datsun Automatic Transmission designated as 3N71B is the 2nd generation “B” automatic transmission, found in Datsun 240z 260z 280z 280ZX. There were 5 different models for this transmission. Below is a table I created to summarize the specs for the 5 different models. The changes were probably in the clutches ( number and material), the clearances and stall specs changed also. There were 4 different stamps on the torque converter, they were probably redesigned also. The differences could also be they changed the manufacturer of components.

These images are from the 1977 Datsun 280z Factory Service Manual by Nissan Motor Corp

Images from the Automatic Transmission section, for the 3N71B transmission from the 1977 Datsun 280z and the 1982 Datsun 280ZX FSM. The 1980 Datsun 280ZX Factory Service Manual had the first Major Overhaul Procedure in it. If anyone has the FSM for the Jetco 3N71B Automatic Transmission please email me.

The internal workings for an automatic transmissions are completely different. There is an input and output shaft, but no counter shaft. The shifting is done with solenoids and control valves, based on fluid pressures. Check out the factory service manuals, there are diagrams and flow charts for shift points and data.

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