80 series L/C

When does it happen?
After you have changed from reverse to forward?
Could be the diff pinion.

They all do it to some extent till something breaks.

Hi Ray,
Does it sound like it from the front of the vehicle or at the rear or in the gear box area?
Could be a front shaft uni joint or rear one that's gone.
As Ross said, maybe a pinion bearing/shaft, either front or rear.
Climb underneath and grab hold of the drive shafts and feel for any movement in the uni's. There will be a little movement in the gearing.
Give that a go.

Hi Ray,
I have had that same clunk in mine for the past 14 years. I have had it checked on a regular basis over the years but was led to assume that there is nothing wrong, it is just something inherent in the vehicle. I now adjust my driving to minimise it occurring. I have heard the that others also do the same.

Steve

The 80 series have the nickname of "the Clunkers" and my 97 model does it also.
Providing you have checked the obvious things like uni joints, suspension bushes and tailshaft splines I wouldn't worry about it.