# Diff oil and additives for safety-trak



## deanhickey (Apr 6, 2015)

I am a little confused on the right oil and additive to use in my diff. I have heard that you should only use gm products for the LSD additive and oil. A lot of conflicting info out there. I plane to use a 80W-90 gear oil that is rated GL4 and GL5 and Amalie LSD additive (4oz). Does it make a difference what brand you use? I have looked at different threads and they don't quite answer my questions. Thank you in advance for any comments.


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## Old Man Taylor (May 9, 2011)

I do not use the GM additive as I've had bad luck with it. I run Moroso Climbing Gear lube with the Ford posi additive.


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## O52 (Jan 27, 2019)

GL4 Valvoline 85-90 with the Motorcraft (Ford) additive in my El Camino.


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## Mine'sa66 (Oct 30, 2019)

If an early Pontiac rolled into the shop with a safety trac rear in it, I'd have to look up what to use lol.
I just had a 12 bolt built for my 66 from JD Race. He was very specific. 80-90 or 75-90 NON synthetic with 8 oz of any brand limited slip lube. 1000 miles, then change it. I'm a synthetic oil guy, but that's what he said to use so I did. I'm around 1k miles so next week I'm changing it. That combo has yielded virtually no chatter at all even though he said to expect a little. As I mentioned, I don't know for a fact if that translates to a safety trac, but I suspect it does.


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## p.rat75 (Oct 26, 2019)

This reply isn't focused on the Pontiac limited-slip, but on the one in my Ford F-150. I change the rear's oil every 30K mi. The previous change was with Valvoline gear oil with GM limited-slip additive #1052358 added (had it on hand). The clutches in the carrier would chatter consistently around low speed corners. With the latest change (a couple a thousand mi. ago), I used the same oil, but used Motorcraft XL-3 additive instead of GM's. Guess what...no more chatter! Completely gone! I am not a petroleum chemist, but it seems to me that there is a difference in the limited-slip additives. Just thought I'd let others know my experience.


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