I have been looking for discussion on LS axles in our trucks and haven't really seen much. I am just wondering what everyone uses and what experience you might have. The current oil in my axle has 75k on it so I'll be changing it here pretty soon. I was thinking either Amsoil or RP, but haven't decided yet. The last change, I went with conventional Valvoline 85-140 with the LS additive because I tow heavy. I want to go synthetic this time and keep it that way.

On a side note, I checked it about a month ago and it was clear and clean at the fill hole and still up to the level. I was pleasantly surprised at that considering how many trips we have taken with the trailer and 100* plus temps when traveling. Thanks for the input if you have any.

 

I use RP and a bottle of that stuff from Ford's.

 

Been pretty happy with it Glenn? Do you remember what weight you used? I have heard good things about RP as far as gear oil and I can buy it off the shelf.

 

My LS was inop since I had the truck pretty sure. But I believe ford calls for full syn 75-140 and the LS additive Of course.

I'm curious what driveabilty will be like with an actual functioning LS. I'm not sure if you saw the pics of mine. But it was pretty much trashed. green has an open diff.

Edit. I stand corrected. The book calls for 80-90

 

I like the 140 for heavy towing and hotter desert temps in the summer since that's when we will do most of our traveling.

 

I've been happy, did that on the Mare also! (no need to change it Todd). I used the 140w. Out of curiosity this summer in a field I stomped on it and both tires left a nice mark for a long way,

 

MOST synthetics already have the friction modify built into them.
Adding friction modifier to synthetic oil will make the Limited Slip Not work

 

when we built diffs at ford the newer trucks take syn and new clutches got soaked in the stinky stuff. a bottle of it went in. the clutch kits came with it and the tag specified synthetic. maybe im doing it wrong but my ls works just fine with the stinky and syn.

hey brad, one more time, what was your shock length with u codes and the pmf? I have searched for where you have stated it but give up after 2 hrs of searching.

 

21" If I remember Correctly

 

Thank you. I'll write it down.

 

75-140 Mobil 1 at a not so cool 18$ a qt...its like 15.50 off amazon though. Master pro and those other brands are starting to come out with it for 14$ a qt. Used to use the valvoline stuff for 9.99.

I need an oil well in my back yard!

 

You and me both. I've always liked Valvoline oils. I am still thinking RP since I can get it here for $13 with our discount.