Landcruiser 80

Check for play in your front drive plates and shafts ...The splines wear and produce a loud noise.

mate had similar, thoough diff was buggered but turned out splines on diff end of front axle were totaled.
$2000 for bits from toyota and $400 from after market comes complete with axles which many mechanics use around town without anyone realiosing anyhow.

regards'GN

Hi Ray, The constant velocity joints and splines in the front axles often give similar noises. Backlash, a clunking noise heard when backing off the accelerator sometimes, is also a problem sometimes in these AWDs.
You say your problem is in the transmission though from which I presume you are saying gearbox. It therefore might be in the centre diff. This is as helpful as I can be given the info supplied.
Regards, Bruce.

Hi Ray
I have an 80 series, auto, petrol model and I get the same problem when basically 'Free Wheeling' down our street which has a slight downwards slope towards the 'T' junction at the base of the 'Hill'. Mine has been doing it since new some 15 years ago. Personally I do not see it as a problem! I find that if it becomes annoying a slight increase on the throttle cures it.
Regards
Brian