Differential gear oil question.
#1
07-29-2003, 05:39 PM
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Differential gear oil question.
I went to AutoZone to buy gear oil for my front and rear diff. They did not have the same wieght spec in the owner's manual. But cash register dude said the Mobile 1 syn would do. I have put Mobile 1 in my old Chevy, and no problems. Since the availability of the exact spec oil is hard to find, will I do damage if I don't use the spec. I am in a hot climate, and do limited hauling. Oh, yeah I have an '02 5.4 4x4 screw with 83K miles.
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07-29-2003, 06:29 PM
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#3
07-29-2003, 08:19 PM
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Summit Racing sells Red Line gear oil in all sorts of weights for 8 bucks a quart. You're in Memphis, so you should get it pretty quick (it'll probably ship out of their Ohio location). Don't forget the friction modifier if you have limited slip, you can get that from your Ford dealer 
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08-20-2003, 07:03 AM
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After putting the Mobile 1 syn in the rear diff, I noticed on the back of the bottle that it was 75-90W. I noticed what I put in was not near as thick as what came out. I got nervous. I looked every where (except the Ford Dealer) for the spec 75-140W gear oil. The closest I could find was Royal Purple 85-140W at Napa. Napa dude said the Ford dealer up the road buys it for their shop, and that the only place to get 75-140W is at a Ford dealer @ $13 a qt.
So, is the rear end of my '01 4x4 Screw going to dissintegrate?
So, is the rear end of my '01 4x4 Screw going to dissintegrate?
#5
08-20-2003, 12:53 PM
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#6
08-20-2003, 09:27 PM
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Differential gear oil question
The 85W won't hurt it any. You can get the 75W140 from royal purple website and I bought it at CarQuest for 7.50 a bottle. Local Ford dealerships sell 2 kinds of friction modifier; a Ford brand (about 4 bucks/4 oz) and a Motorsport brand (about 8 buck/4 oz) both are the same....all in the name. There are a couple of auto parts places that sell the friction modifier for a little less but it takes some looking around. Mobil 1 sells for about 13-15 a quart and Ford's is 15-18 bucks a quart. I know you probably already know this, but if your truck is a king cab, you won't find a gasket...just use the gasket sealer.