3rd Gear Whine

[Clint]

Hello! New here, but I have read many helpful things here. I have a problem that started only yesterday. My 2oo3 2.3 liter has had work done over the last few years. Most recent was a couple of vacuum lines, which helped quite a bit. Next was to be the O2 sensor. Starting yesterday afternoon, when i shift into 3rd, all through accelerating there is a high pitched whine. It increases in pitch as I accelerate, and cuts off completely at 4th. I can begin to hear it when i am in 2nd just prior to shifting up. Transmission or motor?
I have not had any transmission work done. I have never changed the fluid. I also have had the same clutch for as long has i have had the truck, if that makes any difference. 144000 miles on this truck. Any ideas? Any help is really appreciated!

 

[Moreflying]

Change the fluid an put a half qt of Hyperlube in the tranny in place of your total fluid change capacity and see if it helps. It could be the diff. though.

 

[Explorin94]

The bearing (pocket bearing) that keeps the input shaft and mainshaft aligned is worn. You should be able to hear the noise in all the gears except 4th gear whick is a 1:1 and doesn't reply so much on support from the counter shaft cluster. If it has just started then you may get by without having to buy an input and main shaft. You will just need a bearing and seal kit.