Toyota Repair: 99 4Runner 3.4l Has Developed A Ticking Noise, oil level, dipstick

Question
Oil changed last Saturday, immediately noticed a ticking coming from front left (facing truck) side of engine.  I thought it was the A/C compressor, as the sound went away when the A/C was turned off.  The sound returned when the vehicle was put in reverse or drive.  So it appears that the sound is only audible when there is a "strain" or drag on the engine.  It sounds like it is coming from right under the valve cover.

Thanks

Answer
Was the noise there before the oil was changed?
Check the engine oil level and make sure it's up to the full mark on the dipstick, I don't see any other possibility that could have caused a noise just by changing the oil.
If it was a valve noise it would be there at all times even out of gear at idle, if the noise goes away when the A/C is turned off there may be a problem with the a/c clutch or the bearing in the clutch on the front of the a/c compressor.