trans Lock Up sensor?
 

I'm having problems with shifting my 1995 V6 Z34 monte carlo - someone told me it was a lock up sensor.. Anyone know what and where the lockup sensor is???? on the engine or trans? this person said it was a $15.00 item and can be replaced in 5 minutes with a 10 mm wrench.. anyone got any ideas? please email me direct buddney@carolina.rr.com -thanks in advance