Hello everyone, I have a 2008 F150 FX4 with the 3.73 gears and LSD and I was just at the ford dealership to pick up a tube of LSD additive and the service dept told me to put 2 bottles of additive in and change from 75w140 to 75w90 or 80w90. They only put in the 75w140 until the warranty was up. He said that the problem is if your not towing or hauling all the time, condensation builds up due to it not getting hot enough? Is this true?(I don't tow or work it) I live up here in Canada where the winter temp hits -40c at times. Anybody know of this issue, Help! Thanks in advance...

 

I drained my factory stuff out and went with 75w90 synthetic and 1 bottle of FM..Mine seems to run fine, and I kno about the -40 stuff too