Wondering if anyone has run into this concern. I have a 2001 ram with a 46re trans that makes a bearing type noise in 3rd and 4rth gear only. The noise sounds like a bad bearing (whine) or a planetary gear failing. The tone of the whine will change speeds when the trans shifts between 3rd and 4rth. The problem is I have the trans completely disassembled and I can not find anything wrong. All the bearings and planetary gears feel fine. There was no metal in trans pan either.
Thanks in advance for any ideas.

Last Ram with a 46RE that I had, had a similar high pitched whine....torque converter let go, flooded the tranny with ground metal before being diagnoised

Everything is 1 to 1 in third - having a noise in third doesn't make much sense. There is very little preload on the #1 bearing in third - only 0-5 psi pre-filling the OD piston. If that noise is faint then it gets much louder in 4th then the first bearing to suspect is the #1 - that's the one on the OD piston - and that is on the top of the overdrive unit when you pull it off the trans. Sometimes it sticks to the OD piston. That OD piston should have a thick steel shim and the #1 bearing. The next one to get loaded on the 3 - 4 shift is the #2 bearing, the #2 is under the sliding hub spring seat - fits between the seat and the planetary. The next is the #3 - it rests under the ORC cam in the OD unit. The other bearing that gets loaded on the 3-4 shift is the output shaft bearing - it's in the back of the overdrive unit. It gets 800# plus load in OD, the OD piston shoves everything back and the only thing that stops it is this bearing.

Look the planetary over real good - real fine pitting in the teeth will cause noise. Usually the sun gear gets this pitting well before the pinions do in the planetary.

Thanks for the insight. Yes the noise is only there in 3rd and 4rth. It is not there in reverse or 1rst or 2nd. The noise sounds similar to when a pinion bearing is bad in a diff but it is for sure coming from the trans. It is pretty loud and can be heard outside of truck if it drives by you. When the trans shifts from 3rd to 4rth the speed of the noise changes with the shift.

Converter lockup occurs in 3rd and 4th....fluid leakage at the sealing rings can cause a high-pitched whine.

Just a update. Since i can not find anything wrong i am just going to replace the 3 torington bearings and the rear output shaft bearing in the od unit and put it together and see what happens. Since it is fully apart it will get new seals and seal rings.