On a serious note, although I've never seen it happen, I can see how a seal could be dead in the auto transmission (If that's what you have) and it could be pumping fluid up the cable and out behind the speeder meter. I'll probably get shut down on this, and maybe rightfully so. I normally work with manual transmissions. Not much experience with autos other than getting rid of them.
'78 CJ7 (A 360 V8 powered mixed bag of parts)
'80 CJ7 (98% original and gonna stay that way)
'12 CTD 3500 Dodge (Tow rig and daily driver)
'05 Western Star/Cottrell Auto hauler (Big tow rig and means of paying for the Jeep habit)