alright guys. I have 4.57s and they a bit noisy. I am looking to quiet them down a bit. I am currently running Mobile 1 75w90LS and am looking to put in amsoil Severe gear.

I have searched and found that 75w110 is more recommended for coldest climates. Here in NC i might see snow a day or two out of the year and temps usually get coldest at 28 degrees.

For now i was curious about 75-140 and if it will help keep the noise down vs 75w110.

What are your thoughts on these weights?

 

Did you know Richmond Gear recommends 75W-140?

The 4.57's and later 4.57-R's are noisy.
Thicker oil will quiet them down but not much, it's more like they keep the noise level constant when they get hot.

Personally I would never ever run any 75W-90 oil in a 4.57(-R)

The pourpoints of the oils you mentioned are low enough for the climate you live in.

 

I use the Amsoil 75/140 in my 4.57

 

is anyone familiar with Red Line Lightweight Shockproof? one of my customers races several different cars and uses it, and offered me some; i have no idea if it's useable in our cars though (stock diff.)

grandmaster, not trying to jack your thread way off course. if you want, i'll start my own thread

 

i am putting in the 74w140 now and we'll see how it turns out

 

heh, really no reduction in noise from the diff.

I did notice the driveshaft input to the diff has quite a bit of play before it engages the wheels/axles. For example: the driveshaft can turn about 1/2 inch before it will turn the wheels. I can hear it engauge the gears when it does begin to turn. Should an 04 diff with 4.57s have this much play? My oem 06 diff doesnt have much play at all if any.