1997 sls 118k background of noise. Car makes a clicking noise like a card in the spokes. This happens (it seems) in 3rd gear. Noise is very throttle sensitive. Let up throttle or push down on throttle and noise goes away. Must be a light throttle application. It seems to be vacuum sensitive. I have unhooked all vacuum devices one at a time as well as the electrics on engine. No change. At light throttle app. Transmission shifts 1st, 2nd then 3rd gear smoothly and is into 3rd gear by 20 mph, if still accelerating smoothly car shifts into 4th gear at 41mph.
I'm beginning to suspect a shift solenoid problem. I overhauled transmission 8,ooo miles ago. Seems fine. I'm at my wits end and need some help in what direction to go. Nothing i've done so far has helped. Noise is driving me nuts....help
thanks for any suggestions tom

 

If, as I understand, the car only makes the noise in fourth gear and the frequency of the noise changes with speed, then bring the car back to the shop who overhauled the transmission because it sounds like there could be a problem with the final drive pinions or the final drive sun gear.

 

What happens on coast down? Is 3rd gear when you hear noise or is noise occurring at that speed? Why was trans overhauled? Noises are terrible to help with, because just can't hear them. Do you feel vibration when noise occurrs, if so where?

 

noise is only heard in 3rd gear at light throttle. any change of throttle up or down and noise stops. can not feel anything. sometimes noise is moderately loud and other times faint. it can be making noise in 3rd gear and i will manually shift to 2nd gear but maintain speed and noise stops also i can be going along in 4th gear with no noise and shift manually to 3rd gear and noise will start. ( at light throtte application ). that's some of the reason i leaning towards shift solenoids. does any of this make any sense ? maybe you can suggest another direction in which to look. i may have tunnel vision and not looking in the right place.
trans was overhauled because of coast down clutch failure due to clogged filter on side of transmission. (didn't know filter was there ). expensive lesson. thanks for any help you can give me.........

 

You have an internal trans problem. The noise is only occurring in 3rd gear, and in 3rd, both of the shift solenoids are off. You most likely have something worn/damaged in the clutch pack/drum, or possibly a thrust washer has deteriorated to the point of allowing parts to rub/touch.
If you want to eliminate anything electrical, dis-connect the trans connector, and drive it around the block. With the connector unplugged, the trans will default to 3rd gear, where the noise is happening. All of the electrics will be non-functional, so they won't contribute to any noise you hear.