Automatic Transmission Specifications (BMW 5 Series E12)

The following automatic transmissions were used on BMW 5-series cars of the first model years: on the "520" - an automatic planetary three-speed gearbox with a torque converter from ZF type 3HP 12-9, on "525", "528" — type 3HP 20.

The selector lever has six positions: "P" - parking; "R" - reverse; "O" or "N" - neutral; "A" or "O" - automatic engagement of I, II and III gears; "2" automatic engagement of I and II gears; "1" — only 1st gear is engaged.

The engine can only be started if the selector lever is in position "O", "N" or "P".

In positions "A" and "2" of the selector lever, when the car starts moving, 1st gear is automatically engaged, and when the accelerator pedal is pressed all the way down, a lower gear is forcibly engaged ("kick-down").

The drive of the front oil pump of the automatic transmission, which supplies oil to the torque converter, locking mechanism and clutches, is carried out from the torque converter in accordance with the engine crankshaft speed, i.e. the pump does not rotate when towing a vehicle with the engine off. Therefore, a faulty vehicle can only be towed with the selector lever in the "O" or "N" position, at a speed of no more than 50 km/h for a distance of no more than 50 km or by disconnecting the cardan shaft from the gearbox.

Characteristics of automatic transmissions

* Since 1975, all models have been equipped with an automatic transmission from ZF, type ZNR 22, the characteristics of which are the same as those of the type 3HP 20.

Working pressure at selector lever positions "P", "R" and "N"

Working pressure when clutch "A" is operating (see photo) and position "A" of the selector lever

Pressure in the torque converter, kg/cm²:

• "520"

with the accelerator pedal position:

• "idle speed": 3.5-4;
• "kick-down": 5-6;
• "525" and "528": less than 4 up to engine crankshaft speed of 1500 rpm.

Pressure in the pressure reducing valve

Pressure in the centrifugal oil pressure regulator at a speed of 50 km/h, kg/cm²:

• "520": 1,10-1,30;
• "525", "528": 1,27-1,35.

Data for adjustment

Gear shift points (at selector lever position "A")

Gearbox oil

Replace the gearbox oil every 30,000 km. This operation is performed immediately after the trip, while the oil is warm. Set the selector lever to the "P" position, stop the engine and drain the oil. Then drain the remaining oil by successively setting the selector lever to all other positions.

Gearbox filling capacity, l:

— at the 1st filling:

• "520": ~4,85;
• "525", "528": ~5.8.

— when changing oil:

• "520": ~1,75;
• "525", "528": ~1.80.

Difference in the amount of oil between the "maxi" and "mini" marks on the oil dipstick, l:

• "520": 0,2;
• "525": "528": 0,6.

Applicable oil: Dexron ATF B 10 128: Dexron ATF B 10 709; Valvomatic ATF, type B, B 10 312.

Tightening torques of main threaded connections, kgf·m

BMW "520"

• Automatic transmission housing mounting stud nuts: 0.5-0.8.
• Hexagonal nut of toothed sleeve: 1.5.
• Throttle control cable threaded connection: 1.5.
• Hexagonal nut of the automatic transmission parking lock device: 1.0.
• Plug with a diameter of 10 mm for the automatic transmission housing: 1.5.
• Torque converter housing and gearbox extension mounting bolts: 2.3.
• Starter lock and reversing light switch: 3.5.
• Threaded plug (M18) of the torque converter housing 3.5.
• Oil pump mounting bolt: 1.0.
• Speedometer drive bushing lock bolt: 1.0.
• Cylindrical head bolt (M6) of centrifugal pressure regulator: 1.0.
• Output shaft flange mounting nut with flange: 10.0-12.0.
• Pressure regulator mounting bolt: 0.8.
• Oil pan mounting bolt: 1.0.
• Drain plug: 3.5.

BMW "525", "528"

• Bolt (M6) for fastening the hollow shaft to the torque converter housing: 1.0.
• Bolt (M6) for fastening the pump to the torque converter housing: 1.0.
• Automatic transmission housing mounting stud nut: 0.5-0.6.
• Nut (M8) for fastening the torque converter housing to the gearbox housing 2.2-2.5.
• Output shaft flange nut: 10.0-12.0.
• Oil pan mounting bolt: 0.8-0.9.
• Bolt for fastening the throttle control cable bracket to the automatic transmission housing: 1.5-2.5.
• The nipple for fastening the oil line tube to the torque converter housing: 4.0-4.5.
• Threaded plug (M18) of the torque converter housing: 3.5-3.9.
• Threaded plug (M24) of the torque converter housing: 6.0-6.7.
• Threaded plug (M10) of the torque converter housing: 1.5-1.7.
• Bolt (M10) for fastening the leading flange of the torque converter: 4.3-4.8.
• Bolt (M8) for fastening automatic transmission to engine block: 2.2-2.4.

Since the 1977 model year, some characteristics of the ZF automatic transmission type 3HP 20, installed on the "525A" and "528A" models, have been changed.

Automatic transmission characteristics

Data for pressure check

Gear shift moments

Speed of engaging a lower gear when moving the selector lever, km/h:

• from position "A" to position "2": 130;
• from position "2" to position "1": 79.

Since the 1978 model year, some characteristics of the ZF ZNR 22 automatic transmission installed on the BMW "525A", "528A" and "528iA" have been changed.

Characteristics of automatic transmission ZF 3HP 22

Working pressure

Gear shift points (with selector lever in position "D")

Low gear engagement speeds (with selector lever in position "P")

Data for adjustment

Tightening torques of main threaded connections, kgf·m

• Automatic transmission mounting bolt to engine block: M8: 2.5-2.7; M10: 4.7-5.1.
• Bolt for fastening the gearbox extension to the gearbox housing: 2.3-2.5.
• Oil pan mounting bolt: 0.8-0.9.
• Oil pan drain plug: 3.5-3.9.
• Threaded plug M 18x1.5: 4.0-4.5.
• Output shaft flange mounting nut with flange: 10.0-12.0.
• Torque converter mounting bolt to drive flange: M10x16: 4.7-5.1.

Automatic transmission brand Borg Warner type "65"

In a variant version, the BMW "528A" was equipped with an automatic three-speed planetary gearbox of the Borg Warner type "65" with a torque converter. Marking: 032F.

Gear ratios:

• 1st gear: 2.39;
• 2nd gear: 1.45;
• 3rd gear: 1.00;
• reverse: 2.09.

Speedometer drive ratio: 2.50.

Torque converter type: SS 11.

Torque converter diameter, mm: 280.

Permissible imbalance of torque converter, gf cm: 46.

Non-flatness of welded ears for fastening the torque converter, no more than, mm: 0.254.

Working pressure with throttle control cable disconnected, kg/cm²:

• at full throttle position of the accelerator pedal: 3.5-4.6;
• with the accelerator pedal in the kick-down position: 1.4-1.9.

Data for adjustment

Radial clearance between gear and pump body, mm: 0.023.

Maximum axial clearance between gears and pump body, no more than, mm: 0.054.

Gear shift points (at selector lever position "A")

Since the 1980 model year, the ZF 3HP 22 automatic transmission was installed on the 518A, 520A, 525A and 528iA models.

Characteristics of automatic transmission ZF 3HP 22

Working pressure

Data for adjustment

Distance between hydraulic control unit and plunger of pressure reducing valve, mm: 11.5.

Gear shift points (with selector lever in position "D")

Downshift speeds (with selector lever in position "D")

Since the 1981 model year, some characteristics of the ZF ZNR 22 automatic transmission installed on the "525A" model have been changed. Marking on the crankcase cover: 170.

Letter marking: RK.

Torque converter marking: W.

Since the 1982 model year, some characteristics of the ZF 3HP 22 automatic transmission, which was installed only on models, have been changed "520iA", "525iA" and "528iA". These changes concerned mainly the gearbox of the "525iA" model.

Marking on the crankcase cover:

• "520iA": 232;
• "525iA": 171;
• "528iA": 184.

Letter marking of the gearbox and torque converter:

• "520iA": RC and P;
• "525iA": RY and C1;
• "528iA": PZ and D1.

Features of the BMW "525iA" gearbox

Gear shift speeds (with selector lever in position "D")

Low gear engagement speeds

Tightening torques of main threaded connections, kgf·m

• Automatic transmission mounting bolt to engine block: M12: 7.8-8.6; M10: 4.7-5.1; M8 2.2-2.7.
• Torque converter housing mounting bolt: 2.3-2.6.
• Oil pan drain plug: 1.5-1.7.
• Nut for fastening the oil filler pipe to the oil pan: 10.0-11.5.
• Speedometer drive sleeve: 1.0-1.1.
• Output shaft flange mounting nut with flange: 10.0-11.5.
• Torque converter mounting bolt to drive disk: M8: 4.7-5.0.