Limited Slip additives: what exactly do they do?
- Thread starter pgtr
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According to Red Line, their FM additive does not really affect wear, but it will decrease friction(more mpg) and heat. That is why they still recommed the regular 75w90 or treating the NS with FM even in a open diff.
Thanks Mike! That 2nd link was awesome - EXACTLY the info I was looking for and then some. (my browser had trouble w/ the frame on the first linek but not to matter - the 2nd was great).
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On a related subject - this might suggest that if you are going to use a GL-5 in a standard manual transmission: that a GL-5 WITHOUT any limited slip additive may provide better syncho performance over a GL-5 WITH limited slip additives?
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On a related subject - this might suggest that if you are going to use a GL-5 in a standard manual transmission: that a GL-5 WITHOUT any limited slip additive may provide better syncho performance over a GL-5 WITH limited slip additives?
Yep.
There are of course open axle differentials that don't really care about limited slip additives I suppose thus 'NS' and other brands of plain GL-5 would be fine. But I doubt the additive will hurt either.
But strangely enough there are manual transmisions made whose manufacturers explicitly recommend GL5 only and who use copious quantities of yellow metals. See my thread where I am looking for other makers besides GM that list GL5 only for their manual transmissions.
Besides sychro rings are there any other parts in transmissions that could be 'yellow' metal based? What about bushings?
There are of course open axle differentials that don't really care about limited slip additives I suppose thus 'NS' and other brands of plain GL-5 would be fine. But I doubt the additive will hurt either.
But strangely enough there are manual transmisions made whose manufacturers explicitly recommend GL5 only and who use copious quantities of yellow metals. See my thread where I am looking for other makers besides GM that list GL5 only for their manual transmissions.
Besides sychro rings are there any other parts in transmissions that could be 'yellow' metal based? What about bushings?
With a standard open axle arrangement (no LSD) and given a choice - would you prefer a gear oil (say GL-5) that includes or claims to be compatible with LSDs or one that doesn't include additives and is not specifically compatible with LSD clutches? ...and why?
thanks,
thanks,
FYI, I recently replaced the differential oil in both front and rear axles on my 01 Isuzu Trooper with LSD/TOD. I have previously used 80W-90 GL5 with LSD additive but this time I used Pennzoil 80W-90 GL5 with no LSD additive since the Pennzoil claims that "because of its unique formulation, neither LSD additive is necessary, nor is one recommended." So far, I haven't heard any chatter or other noises from the LSD. While I was under the truck, I also did several drain/refill cycles with a case of Pennzoil ATF.
"TOD" ... ?
"because of its unique formulation, neither LSD additive is necessary, nor is one recommended." I usually interpret this to mean that the LSD additive or equivalent is already included with the lube. THis was what I was referring to when I said it was already pre-mixed in with the bottled GL-5. One can argue the semantic difference between the factory mixing an additive in explicitly or somehow claiming their formula doesn't need it but it's teh same end result either way - it's appropriately friction modified for the LSD - 6 one way, half-dozen the other.
"because of its unique formulation, neither LSD additive is necessary, nor is one recommended." I usually interpret this to mean that the LSD additive or equivalent is already included with the lube. THis was what I was referring to when I said it was already pre-mixed in with the bottled GL-5. One can argue the semantic difference between the factory mixing an additive in explicitly or somehow claiming their formula doesn't need it but it's teh same end result either way - it's appropriately friction modified for the LSD - 6 one way, half-dozen the other.
No prob - thanks for the translation. I sometimes sling the term 'Posi-trac' but I think that's a GM parlance for 'limited slip differential' aka 'LSD'
Anyway unless someone can clarify further, my logic suggests taht IF (for whatever reason) you install a GL-5 in your manual transmission that a 'plain vanilla' GL-5 without any sort of 'LSD' specific performance is the better performer for synchro action.
Anyway unless someone can clarify further, my logic suggests taht IF (for whatever reason) you install a GL-5 in your manual transmission that a 'plain vanilla' GL-5 without any sort of 'LSD' specific performance is the better performer for synchro action.
Mike,
Thanks for the links. The second one, however helps to confuse instead of clarify the difference between extreme-pressure/anti-wear agents and the friction modifiers for smoothing clutch takeup in limited slip units and automatic transmissions. EP/AW agents were his primary focus.
Thanks for the links. The second one, however helps to confuse instead of clarify the difference between extreme-pressure/anti-wear agents and the friction modifiers for smoothing clutch takeup in limited slip units and automatic transmissions. EP/AW agents were his primary focus.
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