First of all I really don't feel like taking the rear end in pieces again cuz last time I put 80w90 in mine....a week l8er I had 2 change all the bearings in the rear end($$$$ out the window)!!!And ford keeps telling me NOT 2 put 80w90 for that exact reason and from what I can understand the bearings aren't the same depending on witch rear end u have and I'm trying to find out is if it's bad 4 it and what difference does it make?!!!! I'll give em' a call on Monday see what they say and if 80w90 or non synthetic is an obligation or recommendation!!!!!

 

OK, I've been running some sort of Royal Purple crap in my TrueTrac since March. I've put at least 800 miles on it since then. I only recently started to have slight chatter.

I don't know what to do. The shop guy swears by it, Ford is clueless, and Eaton says never use Synthetic.

 

i think your last 5 words is the way i would go.

as a guy who plays with bearings every day, that go through more turmoil, neglect, and abuse, let alone retarded thought processes, i would disregard the yahoo who jumped up and down about a bearing going down the tubes because of a swap of oil type/weight.

just do yourself a favor, follow the aftermarket carriers instructions, a bearing will not magically explode itself because you changed oil... if its lubed, it will last. now if you make a drastic change in oil weight, yeah i could understand that.

 

All I can say is listen to Eaton, they make the trutrac not Ford. When I get home I'll post the 800# I got for Eaton trutrac dept. Call them, guy I spoke to was Barney. He told me not to run synth and once I put 80w90 in it all the noise went away.