Should I have done this to my Truck?

I have a 2008 2.7l reg cab base 4x2. Just did a rear diff fluid change at 40,000 miles. I used Mobil 1 75 90w gear oil. The manual says 3.5 qts., but it took all 4!!. Just started to come out of the filler hole so i stopped. Do i need to add anything like lsd fluid? Also, is synthetic ok to use in my type of diff?

 

You should be ok...if you start hearing any chattering from the diff you should add the LSD additive. If you still have your window sticker(marooney, not sure of that's correct spelling) it should say there whether or not you have an limited slip diff. Or you could look through the fill hole to see if the diff is open(non LSD)

 

I read that most lsd diffs have a sticker on them that says "lsd fluid only"
Mine doesnt say that anywhere, but it is a 5 year old truck, so maybe they didnt put that on mine?

 

No mechanical LSD (and thus no need for LSD additive) unless you have a 2008 or earlier TRD Sport.

Stated capacities are for reference only. Always fill the oil to the height of the fill plug. Synthetic is good.

 

Yes that is true they did have that very sticker on them. Usually water or salt or corrosion wears the sticker away and it falls off. You might be able to look through the fill hole with a pen light. But it will still be hard to see if it's an open or clutched diff. If you do hear chattering from the rear when turning then def. buy a tube of friction modifier. Before adding the whole tube drain a little bit of diff. fluid out.

 

I could be off, but I don't think they made a 4 cyl base with LSD... Suspect you're fine.

 

You're fine. I fill mine till the fluid comes out of the fill hole then plug it.

I've heard there are issues with the 2005-2008 Mechanical LSD not liking synthetic, but throw some LSD additive in it when you hear some chatter from your rear end. If chatter continues, swap to old fashion dino oil with LSD additive.

09+ Have an electronic LSD so no need to LSD additive

 

Fluid specifications for most all vehicles are an accurate estimation, however lots of things can affect how much fluid it ACTUALLY takes to fill something up. Truck level, angle of lean, etc. I have never seen a differential or any other component like that have any problems by simply filling it a small amount over. You should be fine.

 

A friend of mine filled his S-10 diff with bar and chain lube about a year ago.... he was kind of a putz and said "they are the same thing dude, they just try to get over on you and charge more for diff fluid.." I never bothered actually checking his logic.. and to this date im sure he was absolutely wrong. None the less that shit head is still cruising around in his bar and chain S-10. (I still say its a matter of time.)

Sooooo this really proves fucko with exception of that my friend is a lucky jackass anf gives you pretty good chances of being in the clear compared to him.

 

Hahahahahaha!!