Transmission Whine

[shiftmx]

The past month I have noticed a slight whine coming from what I think is the transmission. The noise is not very loud but it's noticeable to me when I have the radio turned down. It kind of sounds like a power steering pump whine, or supercharger. It's definitely not the PS pump though.

Here's the thing...the noise can not be duplicated when in park or neutral and I rev the engine. It only happens when I put the 4runner in drive and begin to accelerate in first. The sound gets louder as the RPM's rise but as soon as it shifts to second, the sound is gone and I can no longer hear it.

The trans is an A340E on my 2wd. Fluid was changed with a drain and fill to Mobil 1 ATF around 35k ago and still looks fresh. Shifting is nice and smooth with no hesitation and no metal clunking noises or anything of that nature. If it weren't for this whining noise, I'd say the trans is perfect. The 4runner has 168k on it. Any idea if there is the beginning of a problem or is this just something normal from these transmissions that I haven't noticed until recently?

 

[Toyotayoda]

I had a scare like this a couple months ago, I figured when the trans failed I would deal with it then. Good thing I waited was actually the alternator whining, quit suddenly and without warning too, see if it still makes noise with the alternator belt off.

 

[shiftmx]

If it was the alternator, wouldn't it do it regardless of gear I'm in? It's strange that it only happens in 1st gear.

 

[Black798]

My 98 does the same thing when compression braking in first or just before it up shifts into second. Im not sure what it could be, I've changed the fluid twice, it was never burnt, and put in new shift solenoids and it never changed so I figured it is one of those weird quirks. It could be a bad bearing or something but it isnt getting worse in my case.

 

[Toyotayoda]

If it was the alternator, wouldn't it do it regardless of gear I'm in? It's strange that it only happens in 1st gear.

I'm with you on that, mine would whine worse when in gear, whine seemed to disappear altogether while moving, but once alternator was replaced haven't heard the whine since.

 

[4runnerWiniarski23]

How is your rear diff??? I had a slight whine for some time before my diff gave up. Same thing as yours, would not duplicate in anything but driving down the road.