Transmission Overview

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All Datsun 1200s were fitted with a 56-Series_Transmission. Most Datsun 1200s come with a 4-speed floor shift manual transmission (FS4W56). Some Standard models had a 3-speed column shift (R3W56). In Japan, the special GX-5 model came with a direct-fifth (non-overdrive) 5-speed (F5W56).

Main article: 56-Series Transmission

Also see:

• Automatic Transmission
• 5-speeds

• 56-series Transmission, small and light

In the United States, Canada & Australia, all manual shift 1200s had the 4-speed transmission. The two competition four speeds [Option 1 & 2 four speeds in 56 series only] & the five speed was also sold by Datsun Competition in close-ratio and wide-ratio versions. In the five speed version, only the close ratio Option 1 gearbox was offered by Datsunsport Australia, not the standard five speed when I enquired in 1981.

Note that the 4-speed transmission was redesigned in April 1973. Gearsets are not interchangable between early and late transmissions.

The standard 4-speed was well suited to the A12 Engine's torque curve. With a steep 3.757 first gear and a medium-steep 3.90 rear Differential pushing small-diameter 12" Tires, it gave the little 1200 engine enough torque multiplication to take off easily, even with no throttle input. Yet top (4th) gear was good for 90mph. The 5-speed improved upon this by adding an extra gear between 1st and Top.

Powerflow Diagram

F4W56 gear train

The countershaft always rotates with the input shaft. The output shaft (mainshaft) does not move when in neutral -- the main gears just spin freely. When the shifter is moved, it pushes one of the synchro collars against a gear, locking it to the mainshaft. Reverse is a special case, it pushes an idler gear between the counter and main gears, reversing rotation of the mainshaft.

Maintainence Specifications

3-speed, 4-speed

• Synchromesh type: Warner type. Synchromesh on all forward gears in both 3 & 4 speed models.
• Oil capacity: 1.2 liter (2.5 US pint, 2.125 Imperial pint)
• Oil type:
• Oil Drain plug & Filler plug torque: 4.0 - 6.0 kg-m (29-43 ft-lb)
• Speedometer gear ratio:
  • 17/5
  • 18/5 for Wagon

Lubricants

Use GL-4 80W-90 or 85W-140 multiweight, same as the differential lube.

Nissan recommendation
* API GL-4 
* MIL-L-2105 

Such as:
* Chevron Multiservice Gear Lub. 75,80,90,140
* Esso Gear Oil GP 80,90,140
* Mobil Mobilube EP or GX 80-90,90,140
* Shell Spirax 75EP,80EP,90EP,140EP
* Sunoco Multipurpose Gear Lub. GL-4 80,90,140
* Texaco Universal Gear Lub. EP 80,90,140

1972 USA Owners manual (Page 23) Recommended Lubricants

NOTE: Do not use GL-5 spec differential oil. Many people have reported problems with GL-5 gear lube in their older cars. The problem won't be immediately evident but over time the synchros will wear down. GL-5 is not automatically compatible with GL-4. Reportedly there are a few brands of GL-5 that do not use sulfur additives so if the container says GL-5 AND GL-4 then you may safely use it in the gearbox.

Capacity

• F4W56L:
• F4W56A:
• F4W60L (A14): 1.3 liter
• FS5W60L (A15): 1.2 liter

Ratios

• 3-speed R3W56L steering column shift

  1st - 3.380

  2nd - 1.734

  3rd - 1.000

  Rev - 3.640

• 4-speed F4W56L floor shift

  1st - 3.757

  2nd - 2.169

  3rd - 1.404

  4th - 1.000

  Rev - 3.640

• 4-speed Option 1. floor shift [competition close ratio gearbox]

  1st - 2.862

  2nd - 1.908

  3rd - 1.350

  4th - 1.000

  Rev - Not listed

  Source. Datsun B110 Competition Tune Up Manual 1974

• 4-speed Option 2. floor shift [competition ultra close ratio gearbox]

  1st - 2.169 [Note that first gear is the same ratio as the standard models second gear]

  2nd - 1.593

  3rd - 1.233

  4th - 1.000

  Rev - Not listed

  Source. Datsun B110 Competition Tune Up Manual 1974

• 5-speed F5W56A floor shift

  1st - 3.757

  2nd - 2.374

  3rd - 1.659

  4th - 1.291

  5th - 1.000

  Rev - 4.040

• 5-speed F5C56A floor shift [Option 1 competition gearbox. Supersedes Option 1 & 2 four speed gearboxes]

  1st - 2.676

  2nd - 1.691

  3rd - 1.398

  4th - 1.182

  5th - 1.000

  Rev - Not listed

  Source. Datsun B110 Competition Tune Up Manual 1974

Bellhousing Pattern

See main article: Bellhousing

Weight Comparison

• 17.8kg (39.2 lbs): 56-series 4-speed (B110 edition)
• 24.8kg (54.6 lbs): 60A 5-speed (KPB310 edition)
• 31 kg: 63a gearbox complete with clutch set up (with no gearbox mount)
• 36.5kg: T50 with bellhousing and clutch set up
• 43.5kg: CA18DET 5-speed (rwd edition)

Part Numbers

• 30543-H1600 BOOT-RUBBER [clutch] $1.70
• 32862-G1200 BOOT-RUBBER CONTROL LEVER $3.20 [trans boot] formerly 32862-24900
• 74963-20900 BOOT-CONTROL LEVER [floor boot] $8.35

Rear Seal (includes cover shell)

• 32136-18001 SEAL-OIL REAR EXTENSION -0971
• 32136-H3100 SEAL-OIL REAR EXTENSION 1071-0972
• 32136-G1001 SEAL-OIL REAR EXTENSION 0973-0874
• 32136-G1001 SEAL-OIL REAR EXTENSION 0973- B120/B121/B122

• 32136-H5000 OIL SEAL-REAR EXTENSION 5-speed B310
• 32136-H5000 OIL SEAL-REAR EXTENSION -0779 B310
• 32136-H8900 OIL SEAL-REAR EXTENSION 0879- B310
  • Not interchangeable with earlier