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BMW 5 Series
E12
Transmission
Automatic gearbox
Possible malfunctions of automatic transmission and their causes

Possible malfunctions of automatic transmission and their causes (BMW 5 Series E12)

Sign of malfunction	Cause of malfunction
Gears shift at driving speeds above normal values	1. Throttle control cable adjustment is out of adjustment 2. Seizure of the centrifugal governor clutch 3. Increased clearance of the piston rings of the centrifugal regulator 4. Intermittent operation of the pressure reducing valve
Gears shift at driving speeds below normal values	1. Throttle control cable adjustment is out of adjustment 2. Seizure of the centrifugal governor clutch 3. Intermittent operation of the pressure reducing valve
There is no forced engagement of a lower gear	1. Throttle control cable adjustment is out of adjustment 2. Malfunction of the pressure reducing valve
The selector lever does not move to the "P" position	1. The gearbox control drive adjustment is broken 2. The locking device is faulty
The selector lever does not move to the "R" position	The gearbox control drive adjustment is broken
Forward and reverse gears do not engage	1. Insufficient oil level in the gearbox 2. Destruction of the torque converter blades 3. Insufficient oil pressure
When the selector lever is in position "A", the 2nd and 3rd gears are not engaged	1. Seizure of the valve and pistons for shifting 1st and 2nd gears 2. Seizure of the pressure regulator clutch
When the selector lever is in position "A", the third gear is not engaged	1. Seizure of the valve and pistons for shifting II and III gears 2. Increased clearance of friction discs "8" 3. Malfunction of the valve and friction damper 4. Deformation of the mounting sleeve
The car starts and moves only in third gear	1. Seizure of the valve and pistons for shifting I, II and III gears 2. Seizure of the pressure regulator clutch
The back code does not turn on	1. The gearbox control drive adjustment is broken 2. The clutch damper valve "B" does not work 3. Increased clearance of the clutch discs "B"
Friction noise when shifting gears	1. Throttle control cable breakage 2. Insufficient oil level in the gearbox
Friction noise when shifting from 1st to 2nd gear	1. Seizure of the pressure reducing valve 2. Slipping of clutches "C" and "C'" 3. Throttle control cable breakage 4. Insufficient oil level in the gearbox 5. Seizure of the pressure reducing valve
Friction noise when shifting from 2nd to 3rd gear	1. Clutch "B" slipping 2. Increased clearance of the clutch discs "B" 3. Deformation of the mounting sleeve 4. Throttle control cable breakage 5. Seizure of the pressure reducing valve
Slippage when driving in 3rd gear	1. Slippage or increased clearance of the clutch discs "B" 2. Insufficient oil level or insufficient oil pressure 3. Malfunction of the pressure reducing valve
In position "A" of the selector lever, forced engagement of 1st gear does not occur	Malfunction of the 1st gear freewheel clutch
In position "2" of the selector lever, switching from 1st to 2nd gear is difficult	Friction damper valve "O" malfunction
In positions "2" and "1" of the selector lever, engine braking does not occur in 1st gear	1. Faulty valve and damper of clutch "D" 2. Faulty clutch "O"
In positions "2" and "1" of the selector lever, engine braking does not occur in 2nd gear	Faulty clutch "C"
Metallic noise when engine is idling	1. Destruction of the friction disc(s) (friction clutches) 2. Rupture of welded seams of the hydraulic transformer blades
Gearbox humming at idle speed, disappearing when crankshaft speed increases in the "O" or "N" position of the selector lever	Vibration of hydraulic control unit valves
A whistling noise in the gearbox that gets louder with increasing speed	Satellites need to be replaced
Oiling of the crankcase	1. Damage to the radial cuff 2. Damage to the sealing ring of the front oil pump housing 3. Leaky welds of the torque converter 4. Valve leakage
Oiling of the output shaft flange	Radial cuff damage
Oil leak from oil filler tube	Damage to the sealing ring
Oil leak from drain tube	Gearbox oil level too high
Oiling of the speedometer drive	Damage to the sealing ring

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Article verified: Polikarpov Saveliy

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