Toyota Repair: Differential clank, splined shaft, grease gun

Question
Ted,  I have a 1985 Toyota pickup. It has a 146,000 miles and is two-wheel drive with a four speed manual transmission. Ever since I have owned it [at 132,000 miles] it has had a distinct clink noise when taking off from a start, shifting, de-accelerating. Even when it is parked in gear I can push the pickup back and forth and it makes that metallic clinking. I drained and changed the gear oil in both the transmission and differential. All the fluids looked normal and had no metal on the drain plugs. The u-joints seem normal as does the transmission. When one rear wheel is off the ground the clinking seems to come from the differential. This symptom has not gotten worse in the 14,000 miles I have owned the pickup. What is the most likely cause of this noise? Should I fix it or just live with the problem?   Thank you, Brian

Answer
Check the driveshaft to see if it has a slip joint at either the front or the rear, if it has there is a grease fitting on it, pump grease in it with a grease gun until the grease comes out of the splined shaft, lube all the u-joints at the same time.