Castrol. we found the Valvoline would thin out if the car idled for a few hours ( like working an accident or doing radar ETC).
Then, if the officer got another high priority call, hopped in, hit the lights and stomped it the thin oil couldn't protect the thrust bearing.
A few tours of that and " what is that clicking sound when I put it in drive??"
First one we found was intermittent. So we put the car on the lift running in gear with the Ebrake on. After about 45 min I saw the harmonic balancer move forward about 3/8 of an inch and the noise started.
