Transmission in 1993 Oldsmobile

oldsmobile
noises
transmissions

#1

Hello Cartalk!

Just a quick question. My family owns a 1993 Oldsmobile Delta 88 that has around 94,000 miles. We bought it last year from a used car dealership for my younger sister to drive. Great condition, the only work we’ve done so far was replace the tires and have the front end struts changed.

Recently though, it has been making a “whistling” noise that is audible in the cab while driving. The “whistling” gets louder as the engine revs up and becomes quiter when it shifts into a new gear. It is much louder when the A/C is on and when the A/C is off it is quiter but still audible.

We recently took the Oldsmobile to Colorado with us and it climbed the mountains just fine, but it seems like ever since it hasn’t been the same. My father drove the car, and trust me he wasn’t driving like a maniac.

The speedometer is also sluggish and “sticks” at certain points before catching back up. It’s always been like this and I understand that the speedometer runs through the transaxle. It’s always been a little slow, but now it is more pronounced.



What course of action needs to be taken? Are my suspicions about the transaxle correct? Is it a simple problem with the syllanoids,etc? Thanks!


#2

There is definitely not enough information to condemn the transmission just yet. I notice a simmilar whistle while driving my Riviera. I’ve yet to bother with it. It may be an air intake leak. But my first suspicion would be a worn pulley bearing. When the A/C turns on, the load over the entire drivebelt increases. A drivebelt pulley that was whistling from a bad bearing, would make a louder noise under higher load.

As for your sticking speedometer, speedometers no longer use cables running though the transmission. All cars use speed sensors. Hall type sensors just like the magnet and sensor setups that bicycle speedometers use, just more accurate. The speed sensor on your car produces 40,000 pulses (exactly) for every mile traveled. These pulses are sent to the ECM, which translates them into a distance measurement, and puts that mesaurement over time to make a speed measurement. Then that data is relayed to the instrument panel through a varying voltage signal sent to the speedometer. The higher the voltage, the higher the speedometer twists. You probably have a defective speedometer, as a speed sensor problem would lockout the use of the torque converter clutch and you’d probably notice that.

Your whistling sound is not to be bothered with until it becomes a problem. It will likely not become a problem. I’ve lived with the same whistle for many thousands of miles with no issues. I’d suggest that you look into the speedometer issue though. Your car may have changed after the trip through the mountains simply because the engine is old and starting to get tried and the mountain ride was stressful on the engine.

-Matt