BMW Tech Tip: Hard Shifts/Leak at Torque Converter Seal – UnderhoodService

BMW Tech Tip: Hard Shifts/Leak at Torque Converter Seal

BMW owners may complain of difficult shifting. An inspection performed by a trained technician may also uncover noise coming from the transmission oil pump or a transmission fluid leak from the radial seal on torque converter. Refer to the following tech tip for helpful service pointers.

AFFECTED MODELS:
• Z3 with GM5 from 6/00 up to 7/01;
• E39 with GM5 from 9/99 up to 7/01;
• E46 and E46xi with GM5 from 6/98 up to 7/01.

SITUATION:
1. All shifts are very hard.
2. Noise from transmission oil pump.
3. Hard shifts with FC30 (mechanical torque converter clutch monitoring) in EGS fault memory. A combination of 1 through 3 above.
4. Transmission fluid leak from radial seal on torque converter.

CAUSE:
Situation 1 through 3: Improper alignment of sliding seal in pump; from start of production to July 2001, transmission serial numbers 55000-209255.

Situation 4: Improper alignment of the torque converter guide sleeve in pump; from start of production to transmission serial number 413022.

CORRECTION:
Determine the affected parts; replace as necessary.

PROCEDURE:
1. Remove the transmission oil pan and check the condition of the oil. The oil shouldn’t smell burnt or be excessively contaminated with wear particles.

2. Remove the transmission and check the torque converter for ease of movement. The torque converter should rotate easily.

3. Remove the torque converter and check the sliding surface of radial oil seal on the torque converter shaft for signs of wear (grooves).

4. If the above checks are OK, replace the transmission torque converter housing with oil pump, using a special torque converter housing repair kit, P/N 24 40 7 520 492. Refer to repair instructions 24 40.

5. If the torque converter shaft is grooved, replace the transmission torque converter housing with oil pump (P/N 24 40 7 520 492), and torque converter (refer to EPC). Refer to repair instructions 24 40.

6. If the transmission oil smells burnt, is heavily contaminated with wear particles or the torque converter is difficult to turn, replace the transmission.

For additional information, visit www.alldata.com.

Technical service bulletin courtesy of ALLDATA.

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