New diff : MT90 with or with out additive

[Ali 556]

Hello guys,

gonna install a new diff next week and while i'm @ it i'll change the oil with redline MT90. my question is :

Should i add Limited Slip Axle Lubricant Additive or not? all local guys are adding it 1x240sx and 3 evo's and 2 sti's, for both street and track.

GM Vehicle Care Limited Slip Axle Lubricant Additive - 4 fl. oz. (http://www.worldofmotorworks.com/store/product_info.php?products_id=550)

car is 2JZ S14 + R154 and VLSD (was open diff)

thx guys

Ali

[Mirage]

your VLSD is a sealed unit, an additive will do nothing for it, additives are for changing the friction properties in clutch diffs.

[homeslicej2]

MT90 is a GL4 fluid that our transmissions (many nissans, toyotas, & mazdas) need bc of the brass synchros. The differential needs a GL5 gear oil (at least the stock open diff & S15 helical do) I'm not sure if it matters if it's GL4 or GL5 with a VLSD since the unit is sealed, but I would think using a GL5 fluid would be best & redline carries them with and without LSD additives.

[Def]

MT-90 is a gear oil, GL4 as stated above.

Use 75W-90 or 80W-140(look at the FSM). VLSD doesn't need anything special on the oil, it'll suck regardless of what you fill it with.