additive

[jjanak79]

Do you have to put that limited slip additive to the rear diff. I didnt on mine. To tell you the truth i couldnt get the fill plug off so i filled it from the drain plug and got a quart in there. i really dont want to do it again but if i have to i will.

[scoobymal]

No additive needed,and I would say if you "filled" it from the drain plug,then the diff is now low on oil

[jjanak79]

well, i added a quart to it and i had the drain plug in my hand so there is at least a quart in there. so if anything there is too much in there. idk how else to get it off. subaru wasnt thinking when they made steel bolts and a aluminum casing on that. and i didnt want to put heat on it. that kinda scares me

[svxcess]

Factory Service Manual says to remove the Fill plug and add oil until it is at the mouth of the fill hole. The total capacity is 0.8 quarts of diff oil.




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[jjanak79]

then i should be good then. i put valvoline dura 80w 90 in it. The reason why i asked cause my truck has a limited slip and i called mazda about it and they said they always add a bottle of additive to there limited slip diffs.

[svxcess]

I can't figure out how you took off the bottom (drain) plug and addded a quart to it...

Thats the same as saying you could never drain your rear differential (which only holds about a quart. taking off the drain plug would mean nothing would come out.

The fill capacity is measured at the bottom of the top plug.

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[jjanak79]

i took the drain plug out and the old fluid came out. I COULD not get the fill plug off. So i jerryrigged a system to pump it in through the drain plug. When i thought about a quart was in there i quickly took the my pump thing out and plugged it with my drain plug and screwed it back in. I test drove and no humming or anything so i know theres enough in there. Figure it out now?????

[Blacky]

That's why they recommend you always remove the fill plug first. It's better to have old oil than no oil.

[oab_au]

I must be missing something here.
Why would you put "limited diff additive", in a viscous diff??????

Harvey.

[gbianchi]

I would like to pass on a little trick of mine to removing stubborn differencial plugs, I work in my driveway and was a little perplexed on how to get "Samantha" up my ramps cause she's so low, figured that out, then since the rear end was growling I wanted to check the diff fluid. So now for the trick, half in craftsman ratchet, 2inch extension, bottle jack, correct wood blocks for spacing, medium pipe wrench. Put a considerable torque on the ratchet with the jack, pipe wrench on the extension, foot on pipe wrench, wa la loose plug. BE CAREFUL under there.