Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Leaking Final Drive/Speedometer Impulse Transmitter (33 01 94 (3977))
Reference number: 33 01 94 (3977)
LEAKING FINAL DRIVE/SPEEDOMETER IMPULSE TRANSMITTER
TECHNICAL SERVICE BULLETIN
LEAKING FINAL DRIVE
Model(s): All BMW models
Group: 33 - Rear Axle
Bulletin No: 33 01 94 (3977)
Date: April, 1994
SITUATION
Leaks from the vicinity of the speedometer impulse transmitter may be caused by a misplaced O-ring seal.
CORRECTION
The following procedure should be followed when installing the speedometer impulse transmitter:
The O-ring seal "A" of the speedometer impulse transmitter should be lightly oiled and only pushed on as far as the 45° chamfer, then install the speedometer impulse transmitter into the cover of the final drive. See Fig 1 .
If the O-ring is pushed beyond the chamfer, it becomes squashed which may result in leakage from this area. This information is being incorporated in the Repair Instructions microfiche when they are updated.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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