3rd gear WHINING?!?

[Adonut21]

Im new to the 240 and im trying to buy one, and i found the right one except the owner says it "whines" in 3rd gear. I do not know what this means, or what causes it or if its lethal to the transmission. Any input would be appreciated!!

[locoluna825]

trannies get old some of the gears start winning, my third gear wines but only at low revs although i cant really hear it at this moment over my exhaust. ive heard people say they flush the tranns fluid out and fill it back up with new oil and some treatment and its gone away. but it really depends on the severity of the whine i bet, mine is very light i think it would go away if i did a flush