Thanks to all on this board and Bay 13 for successful rear brake job and transmission fluid replacement. I have not done a terrific amount of car maintenance before, but I love the money I save by doing "simple" jobs like these myself!

One quick question, when replacing the tranny fluid I noticed an intermittent clicking sound that seemed to be eminating from a 3" long cylinder located just below the cold air intake and just aft of the radiator. There were two lines attached to this cylinder (not sure if they are vacuum or what). It seemed as though the idle was affected (would slow down slightly) with the onset of this clicking. The clicking would happen for approximately 10 seconds and then would go away for approx. 30 seconds. Any ideas what this is? I'm not really concerned, just curious.

BTW, compressor not on and this was definitely not coming from the area of valve lifters.