If the cable didn't do it, and..it's coming from the area of the speedometer/odometer, then it's probably the speedo head itself. Does the needle jerk around or is it smooth in it's action? But, you said a transmission noise, so I am a little confused about the location..

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Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.