Philip Lindquist

Hey, This is my first post to your forum, I have been using for a while but am now stumped. I have a 1991 Suburban 2500 2wc 5.7l, when my truck goes into overdrive it won't lock up. At first I changed the fluid, filter and shift solenoids. No improvement, I am in the process of changing the TCC clutch solenoid and 2 times I have received the wrong part. The parts store (Napa) says that part# ATP 1-6710 is a direct replacement. I received 2 different parts but both were the same part. Mine from 1991 is shaped a little different and from what I have read the early ones had a resistance value of 20-40 ohms, the newer version should have 10-15 ohms when working. The 2 new solenoids I have received both were right at 10 ohms. Does anyone have the correct part# for the early TCC solenoids, I'm tired of driving 45 in 3rd. Thanks in advance.