noisy transmission

[riocalcio]

I have a 91' Nissan 240 and am hearing this high pitched almost-squealing noise. I recently went to a shop but they could not work on it for for they were not knowledgeable in the area of transmissions. Every part in my 240 is stock, and nothing besides the stereo has been altered. There are 110,000 miles on the car and it has been making this noise for about 2 weeks. Every time I rev the engine past 2500-3000 rpm's, the car makes this noise, and it sounds like the motor would be making it, but the mechanic said it was the transmission. I bought Lucas transmission fix, because the transmission was slipping a little bit, but the lucas fixed it up, but I still have that noise. I would like to know if anyone else has had this problem..and please, any suggestions would be greatly appreciated.

[marshun]

automatic? you changed the transmission fluid right? man i swear i knew this but i just dont remember what the problem was. :P

[navysnail]

take it to a transmission shop and get an estimate.it may be cheaper to get a used transmission from the junk yard