Had a Trans Fault thrown on my 4.6 going to the firehouse. After looking at all my options on the forum. I dropped the pan, dropped the valve body, looked at the rings that I thought would be missing pieces. NOPE. Nothing! I'm thinking solenoids, well hell the pans dropped lets do it. Replaced the 2 solenoids under the pan, bolt up, fill up, same ****, Trans Fault. Now I'm losing it, did an online search, check your TSS and another Solenoid behind that. We'll to Ford I go order the other two outer Solenoids. Thinking this is it. Take them out, put the new ones in, bolt them in, and then plug them in. The 1st one went good, but before plugging the TSS plug in I noticed 1 of the 2 wires was completely corroded off (throwing the P0715 Code). New plug coming in the am. But after 4 solenoids and about 13 qts of fluid this problem is solved. Check your wire harness going to the TSS before dropping the pan.