Positraction Additive

[canbeam]

I tried to search this on the forum but couldn't find the right search word combination. I'm sure it has been discussed many times, I want to change the lube in my differential, and am putting in Brad Penn GL-4 lube, based on what I understand about GL-5 attacking brass parts. I put the same stuff in my toploader. I have a 3:07 posi unit in my car. There are a lot of LSD additives out there, and was wondering what others use, and if there are types of additives to avoid as they may not be suitable for our older cars.

 

[65beam]

I tried to search this on the forum but couldn't find the right search word combination. I'm sure it has been discussed many times, I want to change the lube in my differential, and am putting in Brad Penn GL-4 lube, based on what I understand about GL-5 attacking brass parts. I put the same stuff in my toploader. I have a 3:07 posi unit in my car. There are a lot of LSD additives out there, and was wondering what others use, and if there are types of additives to avoid as they may not be suitable for our older cars.

JEGS sells several different LSD additives that you add to the gear oil. They also carry a Kendall product with the additive preblended in the gear oil. We've sold the tubes of Kendall LSD additive for many years and It has never presented a problem. FYI, Brad Penn is now owned by DA lubricants.

 

[Warren]

I personally took a shiny brand new brass key. I dropped it into API GL5 transmission 90 wt. I left it there for 1 year I pulled it out it looked like it had been sitting in a plastic bag with no oxygen shiny as the day it went in like a brand new penny that probably cost the US government a dime to make or more

 

[65beam]

Dropping a key into oil and letting it set has no comparison to a gear set operating under high heat or extreme pressure. If it is actually a yellow metal the corrosion process has started and is not reversable. Conventional multi viscosity gear oils contain a sulfur phosphorus extreme pressure additive. If you want to see if the gear oil has this additive all you need to do is smell it. It stinks. The main difference between GL-4 and GL-5 gear oil is that GL-5 is intended for use in hypoid gear sets operating under various conditions especially high speed and high torque conditions and the GL-4 is for use with spiral bevel gears operating under moderate to severe speed and load or hypoid gears operating under moderate speeds and loads.. I suggest to my accounts to follow the original specified oil spec and keep in mind that specs have upgraded over the years and are backwards compatible to use under older specs but unless you've changed to a rear end entirely different from the Tiger then under normal conditions GL-4 will be fine. A synthetic oil broadens the temperature operating range of oils but many synthetics are now blended with a percentage of the base oil being refined from crude oil but still retain the advantages of a synthetic. Oils from blenders such as Brad Penn, Redline and others are blended to withstand extreme conditions such as seen under race conditions using additives that can be used up in a short period of driving time, not normal street conditions. Follow what was the original spec and under normal conditions you're fine. If you have a LSD rear then use an oil with the additive preblended or pour in a bottle of LSD additive. How much do you want to spend to achieve the same protection.

 

[michael-king]

I tried to search this on the forum but couldn't find the right search word combination. I'm sure it has been discussed many times, I want to change the lube in my differential, and am putting in Brad Penn GL-4 lube, based on what I understand about GL-5 attacking brass parts. I put the same stuff in my toploader. I have a 3:07 posi unit in my car. There are a lot of LSD additives out there, and was wondering what others use, and if there are types of additives to avoid as they may not be suitable for our older cars.

I used the ford racing lsd addative (friction modifer) bought from summit. Smells like cats pi$$.. I also use Penrite LSD oil

 

[BillRo]

I used LSD additive I bought from Ford. I agree the worst smelling stuff ever.

 

[65beam]

I used LSD additive I bought from Ford. I agree the worst smelling stuff ever.

Since there are specific specs to meet you'll find the brands to be pretty much the same except for a tracer element which will verify the brand it was packed for. Blenders package for many companies so that's the reason for the tracer. Most Ford oils now come thru P66.

 

[canbeam]

Thanks Bob Michael and Bill for the info. Looks like I don't need to worry too much about which additive to use and will see if I can locate your recommendations locally.

 

[spmdr]

I don't know of any brass parts in the garden variety Dana/Spicer 44 PowerLoc Posi.