Transmission Overview

(Difference between revisions)

Revision as of 17:38, 22 August 2008

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

In the United States and Canada, all 1200s had the 4-speed transmission. The 5-speed was also sold by Datsun Competition in close-ratio and wide-ratio versions.

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

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 F4C56L[?] floor shift [Option 1 competition close ratio gearbox]

  1st - 2.862

  2nd - 1.908

  3rd - 1.350

  4th - 1.000

  Rev - Not listed

• 4-speed F4?56L[?] floor shift [Option 2 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

• 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

Bellhousing Pattern

All A-series engines use the same bellhousing pattern. This means any rwd transmission, from B10 to B310, fits any A-series engine.

No other Nissan engine shares this pattern. This means transmissions from Datsun 1600 or any other will not fit an A-series engine.

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 (54.6 lbs): CA18DET 5-speed (rwd edition)