LSD rear diff oil additive question

I've already searched and gone through thread after thread not quite finding what I'm looking for.

I want to change the rear diff fluid in my '07 mechanical LSD. I already read that the safe route was 80W-90 conventional oil and a tube of LSD additive. So today I picked up 3 qts of Valvoline 80W-90 gear oil and a tube of Trans-X Posi-Trac additive.

Two questions:

1. Is this a good additive? Or is there something better I should look in to?

2. This tube is 7oz. I've seen other tubes are 4oz. Is 7oz too much to add? Or should I just stick the whole thing in there? The tube says to "add entire contents of tube to differential", but then says "do not overtreat".

 

I would just use the entire tube. Remember add the contents of tube after the first quart of oil, you don't want to fill with oil and can't add the additive.

 

I used as close to half the bottle as I could and it worked fine for me.

 

Never used that brand, but what I can tell you is I have used this combination with no problems at all...

Go to Ford dealer and purchase 3 bottles of the SAE 80W-90 Premium Rear Axle Lubricant
http://fcsdchemicalsandlubricants.c... Rear Axle Lubricant&category=Transaxle Fluid

Then also purchase the 4 oz. bottle of the Ford LSD Friction Modifier

Add the entire bottle of friction modifier to the rear first then fill with the rear axle gear oil

Mine took close to 3 quarts after I put the friction modifier in

You want the level just under the fill hole

Then drive around for 10 minutes and do a bunch of figure 8's in a parking lot

Come back back home on level ground and check the level again making sure it's just under the fill hole

Take the spare tire out it's so much easier

 

I also bought my friction modifier from Ford, but it was made by Motorcraft or something like that. That with Valvoline 80w-90 havent had any issues yet. Then again, it's only been about 3K miles.

Check with your local Toyota dealer. My local one sells Kendall LSD oil for only $5 qt.


1st time I've heard someone recommend removing the spare. Shouldnt be an issue unless you're tugging around your own "spare tire"......

 

I also dropped the spare when I did my rear diff. If you're not using a pump, it makes it much, much easier to get the bottle at an angle where you an pour.

 

Well that's true. I just assumed everyone would be using a pump.

 

I should have. Although I had to use the 3 quarts and the 8oz of LSD additive, and the oil level was still just barely up to the fill hole. Not sure that the pump I later bought when I did my transmission and transfer case would have pulled out what I needed from those bottles. I may have needed to do some pouring anyway.