I have a 2003 Buick Century in automatic with overdrive. During the past week I experienced a hum and slight vibration at speeds over 20 mph. (The faster I drive the higher the hum.) I checked the transmission fluid. It was brown and pink but did not smell burned. I have not changed the trans fluid in 2 years. I sent it to my transmission guy for an oil change. He said that the 1st gear clutch was having some problem and there was no 4th gear. He suggested another transmission…what do you think?
You’ll need to fill in a lot of blanks. How many miles are on the car? Over all of this time/miles what was the history of transmission service? What kind of a “transmission guy” is this? A person who works almost exclusively on automatic transmissions? A general mechanic to whom you have taken the car for transmission service? A national transmission chain operation?
What the computer scanned for error codes? If so, what were they? (They would look like “P1234”). Was the car driven with a scanner attached? What was observed?
See if you can get a more specific “diagnosis” than “1st gear clutch was having some problem and there was no 4th gear” What kind of 1st clutch problem? Is the computer commanding 4th gear and the transmission goes to neutral at that point? Or is 4th gear never being commanded? (By “commanded” I mean that it is the engine’s computer that tells the transmission what to do).
What does the car do once you get it up over say 50mph? Is it still humming? Does the humming ever go away? Does anything make the humming change? Does the engine seem to be racing? Will the engine race sometimes without you feeling any extra power?
It seems to me that if you had no 4th gear you’d be reporting more than just a humming noise/vibration. If first gear was having trouble you’d also know it well before 20mph, and by the time you’re at 20mph you’re past 1st gear unless you’re really hammering the accelerator. And of all of the ways that a clutch problem in an automatic can show up, humming isn’t really one of them.
So…I don’t know if there’s a way for anyone to say what they think.
If your transmission fluid is pink, it has water in it.