rear differential fluid change

[Randee Bowknee]

i was thinking of changing my rear diff fluid and i was reading in scheduled maintenance manual and saw that it said ford axles have synthetic fluid and there is no need to ever change the fluid unless you have a leak from the diff.....any thoughts on this? change it anyways? or F it? Trucxk had like 120,000 when we bought it and now has 131,000

[02stroke]

i don't know about whether or not you should change it, but if you do be sure to put in the correct fliud along with the additive.

[Hank]

I bought my truck with 101,000 miles and wanted to see the condition of the rear end before I put any additional miles on it. It looked brand new. I replaced mine with AMSOIL. I run a diff. temp gauge now and it stays real cool.

[melmount]

change it, i did.

[Randee Bowknee]

what kind of sealant is used on the rear diff cover?

[melmount]

permatex gasket maker works. I used hi temp red cause thats what I had. I just sprayed under coating over it to cover the red.

[NCHornet]

I don't leave any fluids in my vehicles for that long, I don't care what Ford says!! Ford also says there is no need to change the AT filter, but I do everytime I change fluid. So yes I would change it. You just use a normal permagasket tube, IIRC I use the black on diff covers. If you have a LS you will have to add the anti friction additive. Ford calls for 8 oz, but they also get a really bad wrap for their LS not working. The reason is because to much additive!!! Change the fluid, use a fluid that doesn't contain the additive already because they use way to much also, then add 30 oz of additive, go to a parking lot and do some tight figure eights, if you have chatter from the rear end add 1 0z of additive and repeat. Most take 3-5 oz. If you don't have a LS rear end you don't use any additive.

NCH

[Randee Bowknee]

i do have a LS but its not working so well....alot of vibration when i tow(everyday) around turns

[Randee Bowknee]

So you're saying change to fluid without additive....then add 30OZ of additive?

[ju015dd]

how do you find out if you have an ls rear?