Rearend oil and additives

Ramon · 09-05-2006, 04:29 PM

I know this has been talked about 100 times, but I am wondering if anybody has heard of this mixture of oil. I am a firm believer of BG products. I am using there 75/140 ultra guard oil. A BG rep told me to add there limited slip fluid even if I donot have a limited slip rearend. He said it helps the oil from shearing at high temps. He said the hotter the oil gets the limited slip additive keeps it more stable. I did add some to my rearend to see what happens. I also use there MOA oil additive and super cool additive to my cooling system. I tow a tt and like to keep things cool as I can. Just wondering if anybody also uses there products.

**ArmyAviation** · 09-05-2006, 04:38 PM

Is the BG oil synthetic?. the Titan requires synthetic oil in the rears and front axle, 75w-140. If you want the good stuff get amsiol. BG products are great stuff, I use it in the full system BK44 real good cleaner. Use it evey 20k

Ramon · 09-05-2006, 04:59 PM

Yes, the oil is synthetic.

**ArmyAviation** · 09-05-2006, 05:01 PM

Ok then just asking. I never used any of BG oil. I guess its fine as long as its synthetic.

whiteLE · 01-14-2007, 03:57 PM

Apparently the 04' F150's have had many rear end problems also. A friend of mine mentioned the Ford dealer put in some kind of "super lube" into his rear end after he started having problems. The rear end is now cured.

Anybody else heard of this?

white

KYDeepwater · 01-15-2007, 04:54 AM

A 75/140 synthetic gear lube won't shear at the temperatures seen in a normal rear differential. A limited slip lube could cause long term problems with the front face of the gear teeth, causing them to be polished away.

The "super Lube" is likely a chlorinated parrafin additive that improves the lubricity of the oil. The chlorine reacts with the metal surface and attaches itself to the metal surface, leaving the parrafin molecule to "dangle" and take up space between the metal surfaces. These molecules do help, but the olefin hanging off of the chlorine loves water, and will break down quickly.
Using a quality GL-5 synthetic 75/140 is the best bet. The aluminum cover is likely good for a 20 degree lower operating temperature. If you are having problems, the miracle additives might give you some extra time, but you will have a failure at some point.
I have 50,000 miles on my 2004 SE since 2/14/2004, one of the first ones made. I added the PML cover when it first came out and have had no problems, with very little metal in the rear diff oil when it was tested last.