le 1605

 

I'm using LE1605 too, and used LE607 before that. On the warmer Texas days, the gears do whine quite a bit though. Are you folks that are using 140 noticing any gear whine on hot days? I'm thinking about stepping up the viscosity on my next fill for the summer.

 

I don't really remember the OEM diff, but the Amsoil SAE 190 only made my 4.57 diff a tiny little less noisy.
The noise doesn't get any louder when the diff is hot though, more of a constant level as soon as it's warmed up.

Funny thing is that the noise also seems to concentrate itself around the driver's head
Move your head around while driving and the noise level changes.
Get someone else to drive and sit in the passenger seat and the noise is way less.

One of the things I still want to do is get some good sound dampening material on the chassis where the spare wheels sits and where the fuel filler pipe is, basically that whole area behind the front trunk liner.
The diff sits right under it.

 

Thanks for the info Spitfire. I have one more quart of 1605, so I'll probably go another round with it. I think I'll take a sample of this fill and see what the viscosity really is. It sure seems like 607 was more quiet though.

 

AMSOIL 75w110!

 

LE1605 in my Diff with 4.77's.

 

LE for me as well