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Lucas synthetic 75W-90 - Can I use it in my 02 S-10? 7.625 or 7.5 differential, no G80

825 Views 2 Replies 2 Participants Last post by  PBrooks#259
Hi. From the forum I kinda gather that it is OK (but ideally want to know if it is "good") to use Lucas synthetic 75W-90 in my '02 S-10, 2.2L, 5 spd man, 7.625 or 7.5 differential (not sure which). Is it "good" to use it in this truck? No G80 noted in glovebox sticker. I don't see an LS tag on the differential but I think it is an LS differential. I do haul upwards of 500 lbs or a little more on the bed at times for several hundred miles at a time.

I have been using it for the last 10K miles. I do have a leaking L axle seal--don't know whether the Lucas gear oil affected that, probably just normal wear. I have heard synthetics would maybe break down RTV sealant if used to seal the cover.

VIN: 1GCCS1958 28108074

Thanks very much,
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The oil you picked will be just fine. It covers GL4 and GL5 spec and you should be needing GL5.

You can always use the "limited slip" additive in your non limited slip differential, but you dont want to be caught not using it in a limited slip diff. The G80 locker doesn't have clutches that need the friction modifier, but those same friction modifiers also will help the pawl that locks the G80 moving easily so that it works properly. It is not needed, but it doesn't hurt.
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