e30_in_korea
02-01-2007, 02:40 AM
Friends,
I have a 1989 325i w/ automatic transmission with 158K miles. It is making a very loud ratchet-like noise upon first cold-start (20-30 degrees Fahrenheit) in the morning – loud enough to attract attention from pedestrians walking on the sidewalks. Here are some more descriptions of the strange behavior:
1. The noise seems to be coming from the vicinity of the torque converter/bell housing.
2. The intensity of the noise is directly proportional the automatic transmission fluid (ATF) temperature; the noise diminishes as the temperature of the ATF increases.
3. The noise disappears once the transmission reaches its normal operating temperature.
4. If the temperature of the ATF drops – the noise will return.
5. Prior to the ATF reaching the normal operating temperature, it is occasionally possible to shut the engine down and then restart it to eliminate the noise.
7. I have noticed no negative affect on the transmission performance or any other noise or strange symptoms.
8. I have replaced the starter. That action made no difference.
I decided to add a bottle of Slick 50 Automatic Transmission treatment to the ATF to see if it would make a difference. Well, it did. It seemed to lessen the severity of the noise dulling it a bit. The next morning the shift from Park to Reverse and then to Drive seemed to take an inordinate amount of time. I drove it for about 30 miles with the Slick 50 until earlier that afternoon.
Then…..
I wondered what would happen if I ‘punched-it’. I punched the accelerator to the floor. The xmsn dropped down to a lower gear like it should and we took off. At about 7K RPM I lost power to the drive wheels, the tach pegged, and I found myself coasting with the engine maintaining idle speed. At about 40MPH, power to the wheels was restored. There was about 1-2 second latency between gears as the xmsn shifted up with no power to the wheels and the tach spiking during shifts. Sudden accelerations rendered the drive wheels without power for 10-20 seconds. Shifting from Drive to Neutral to Reverse yielded a 5-7 second latency.
I helped her limp home and she is sitting all alone in the parking garage demanding attention. I am no longer driving it.
One of my coworkers suggests the possibility that the xmsn oil pump has failed. I am considering replacing both the pump and the torque converter. I have not pulled the tranny, yet.
I have recorded the noise to an *.mp4 file and I will be glad to e-mail it to anybody who wishes to listen. It is a large file - 1.2MB.
Any ideas?
Thanks.....
I have a 1989 325i w/ automatic transmission with 158K miles. It is making a very loud ratchet-like noise upon first cold-start (20-30 degrees Fahrenheit) in the morning – loud enough to attract attention from pedestrians walking on the sidewalks. Here are some more descriptions of the strange behavior:
1. The noise seems to be coming from the vicinity of the torque converter/bell housing.
2. The intensity of the noise is directly proportional the automatic transmission fluid (ATF) temperature; the noise diminishes as the temperature of the ATF increases.
3. The noise disappears once the transmission reaches its normal operating temperature.
4. If the temperature of the ATF drops – the noise will return.
5. Prior to the ATF reaching the normal operating temperature, it is occasionally possible to shut the engine down and then restart it to eliminate the noise.
7. I have noticed no negative affect on the transmission performance or any other noise or strange symptoms.
8. I have replaced the starter. That action made no difference.
I decided to add a bottle of Slick 50 Automatic Transmission treatment to the ATF to see if it would make a difference. Well, it did. It seemed to lessen the severity of the noise dulling it a bit. The next morning the shift from Park to Reverse and then to Drive seemed to take an inordinate amount of time. I drove it for about 30 miles with the Slick 50 until earlier that afternoon.
Then…..
I wondered what would happen if I ‘punched-it’. I punched the accelerator to the floor. The xmsn dropped down to a lower gear like it should and we took off. At about 7K RPM I lost power to the drive wheels, the tach pegged, and I found myself coasting with the engine maintaining idle speed. At about 40MPH, power to the wheels was restored. There was about 1-2 second latency between gears as the xmsn shifted up with no power to the wheels and the tach spiking during shifts. Sudden accelerations rendered the drive wheels without power for 10-20 seconds. Shifting from Drive to Neutral to Reverse yielded a 5-7 second latency.
I helped her limp home and she is sitting all alone in the parking garage demanding attention. I am no longer driving it.
One of my coworkers suggests the possibility that the xmsn oil pump has failed. I am considering replacing both the pump and the torque converter. I have not pulled the tranny, yet.
I have recorded the noise to an *.mp4 file and I will be glad to e-mail it to anybody who wishes to listen. It is a large file - 1.2MB.
Any ideas?
Thanks.....