I keep hearing different things. I'm thinking the tendency, right now, is that the gears have changed in a way that makes setup require more exact install these days. It's either that or the gear manufacturing is inconsistent because now, all of a sudden, we have what seems like a lot more blame on shops going around. Something had to of change and I personally believe it's something with the gears. Were there bad shops before? Oh yeah, but I think things are leaning to the gear manufacturer.
I was scouring the net to try to lessen my gear whine. Very obnoxious whine between 50-65mph on cruise, no acceleration going on. Goes away with acceleration. Barely audible on decel anywhere in mph range. I will try what a couple of others on another forum tried but may modify that just a little. They used Redline Heavy Shockproof gear oil. One member estimated about a 50% reduction in whine in his Shelby which went through 3 gears setups with new gears trying to eliminate the noise. I may modify this for lower temp operation (winter) and run a 50-50% mixture of the Lightweight Shockproof and Heavy Shockproof.
If one of ya beats me to it, let me know how it turns out. There's a thread on mustangforums about "quieting gear whine solution found" you can check out if you wish.
Now I do question the oil change interval though. I don't think this oil is meant to go near as far as the 75w-140 GL-5 that comes in our cars. I like more info on that if anyone finds something on it. 10k? 20k? 50k?....