What is the whinning sound coming from transmission? on 1994 BMW 540i

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
I have a 1994 BMW 540i with 161,000 miles on it. I hear a whining sound coming from the transmission mostly at acceleration and changing through the first two too three gears.shifting between gears is pretty much smooth. What could it be and is it serious?

(1) Answer
| |
It is safest to have a repair shop familiar with BMW check out the noise or a transmission shop. Perhaps it would be a good idea to check or change the transmission oil if you haven't had it changed in the last 30,000 miles.