I just did the a-z synthetic deal. I was over 15,000 on my diffs so I got them done, and redid my tranny, and trnsfer case. The deal is at from a stop to 15 mile per hour and around corners at that speed I am getting a resonance, and a slight grissling (like a grinding but less). Might have they forgot the graphite additive in the rear diff.
Please anyone who might know big thanks!!!!