The Rover-Landers of BC

There is such a thing as a millitary spec LT77. Is has a lower geared first and second compared to a normal LT77 but other than that it is the same as other LT77s.

If the Cluncking noise is when you accelerate or decelerate it is unfortunately common and it is caused by the input shaft for the transfer case not being properly lubricated. Later model transfer cases have this problem fixed.

If your truck was fitted with a V8 stock and still has the original transmission then it probably is the LT85 and not the LT77

Ratios are listed here for the military and civilian LT77 http://members.shaw.ca/red90/gears.html#lt77

As stated, clunking is not normal. The t. case input splines could be the problem. Remove the PTO cover (6 bolt cover above and left of the parking brake) and inspect the splines and check for back lash. Clunking can also be other parts of the driveline or the suspension. For instance, a worn A frame ball joint clunks when taking up drive.