I was doing my 60,000 mile tune-up and went and bought all the stuff I needed at a local auto parts store and everything went off without a hitch. That was until I was in my garage today and for some reason looked at one of the oil bottles that I had used for my rear diff. The rear diff calls for 75W-140 and 2 of the quart bottles I bought were the correct weight, but one of the bottles I bought (luckily the one I only used about 6-8 oz's out of) was 75W-90. Does anyone know if this will mess up my rear diff and I should empty it back out and refill it, or is it such a little amount that it won't matter?
Also, how can you tell if you have a 8 1/4" or 9 1/4" rear diff?
I've had my truck for about a year an a half now, but only been able to drive it for about 9 months out of that so I'm kind of new on the mechanical side of everything!

 

I would dump it and refill.....or just suction it out so you don't have to break the gasket. I don't think it would necessarily harm anything for general use, but It will definitely have a reduced lifespan....especially if you tow.

 

If it was me I would refill it with the 75W-140.

As for which diff you have, just take a look under the back and compare to these:

IDchry925.gifIDchry825.gif

 

Yea, I think I'm going to drain it and refill just to be safe. The rear diff pictures won't load but I think it may be the network that I'm on right now, going to check again when I get home.

 

change it out!

 

yes armydude...but the ? is do you do alot of towing? if not you can use 75W90 Synthetic and it'll be fine...thats what i do cause i dont tow alot. but yeah mixing and matching es no bueno! that would be like wearing our Class A bottoms with ACU top and Beret! so yeah keep it all uniform and the same!

 

I wish I could wear that uniform... with one shower shoe n one pt shoe, 30 more min of CQ woohoo

 

lucky man! I hate CQ and OMG STAFF DUTY NCO position sucks! lol god i think this is what Privates are for..they need to learn while I sleep!! lol

 

Yea, I hear ya. We used to be able to make SPC run CQ along with us, but now it has to be E-5's only with a joe runner. Home now and time to go camping for the weekend tho!

 

good stuff! be safe drivin and catch a big fish or kill a really big deer! i'm talking about 10 point or bigger!