NS Auto Transmission Noise

[BLOKE66]

Hi Guys
Did a bit of a search and couldn't find anything on this.
Just noticed today when the motor is running(3.2 DID) and brakes are on.....when I select Drive or Reverse I can hear a low pitched noise (like a loud hum) ....this noise stops when Neutral is selected.
The noise appears to be coming from the gearbox area. Being 3/4 deaf doesn't help....this noise may have been there for a while as I usually have the radio come on when I start the car.
Cheers

[BLOKE66]

Mmmm maybe not explaining the situation clearly enough....not sure.
Normally when you select Drive or Reverse the noise level in the cab changes slightly as the gearbox is engaged. Well that noise seems to be louder and more noticeable in the cab.
I recently towed a heavy camper trailer with a "binding brake" for some distance that would have put a bit of stress on the gearbox and Torque converter.I flushed the gearbox with good oil just after I bought it....about 40-50k ago. The oil still looks good...red.
Should I do another oil change to see if that changes the noise level??
Cheers

[BLOKE66]

I know this was a wierd one so i decided to change the gearbox oil.
The oil looked fine on the dip stick but ended up looking pretty dark after purging all the oil out.
The result...a much quieter gearbox......much better gear changes and car drives heaps better.
I'm a happy camper again.
Cheers

[aussieintas]

Hey bloke

Had a similar thing with mine regarding oil colour in the box. When you look at dipstick she looks pretty good, but using a white paper towel and wiping it shows how off red it can be.

Reminds me mine is due a change in the not too distance future.

[BLOKE66]

Yeah it was very deceptive just looking at the oil on the dipstick and when I was purging the oil out several litres came out then it slowed to a trickle...I was going to stop the engine but I waited probably about a minute and then another load of oil came gushing out and that was it. Refilled it and purged till I saw the new oil and reconnected.
The difference to drive the car is seriously noticeable...holds gears longer and heaps smoother.
Cheers