Rear differential oil
 

What weight does it call for? What about capacity? Is one of the typical cone shaped bottles enough for a drain and fill, or does it need more?

I'm probably going to go with Mobil1 full synthetic

I've done this on other vehicles before, but not this truck. Do I just remove the top plug, remove the bottom, let all fluid drain, then install bottom plug, and fill through the top until fluid starts to drip out the top hole, then plug?
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Re: Rear differential oil
 

Usually its 90 weight. My 12 bolt took a little less than 2 quarts, but no clue what your 3/4 ton takes.

I usually do just as you stated----fill until it drips, then put the plug back.

Re: Rear differential oil
 

The procedure is good. Your will need at least 4 bottles (quarts).You will not use all 4. Yes the cone shaped bottle. Typically 80-90 is good. Is it a locker or posi? If so, you may have to add an additive but I am not sure about synthetic lube.

Have fun. i love the smell of gear lube.

Re: Rear differential oil
 

i seem to remember putting in 2 bottles of oil and one of lucas gear oil stuff.

Re: Rear differential oil
 

Thanks. I don't have anything fancy, I don't think. It isn't 4 wheel drive.

My x used to hate it when I smelled like gear lube lmao
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Re: Rear differential oil
 

If it came from the factory with posi, it would be listed on your SPID and the buildsheet you just found.

Re: Rear differential oil
 

a bit less than 2quarts is correct for 12bolt rear

i prefer synthetic for lubrication tranny,rear and wheel beriangs i always do all synthetic// royal purple for the rearends and no worry about posi friction modifiers

Re: Rear differential oil
 

I'm not seeing where it would list that. Can you?

http://i146.photobucket.com/albums/r...psa7e263e9.jpg
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Re: Rear differential oil
 

Driver's Handbook is listing 6.5 pints. I'd avoid using a synthetic, often in an older rear end. They tend to be alot noisier due to thinner lube film. Use quality dino oil and add some of Lucas' additive. You don't have a posi. per the SPID or the build sheet. FYI: That has a 24K mile change interval.

Re: Rear differential oil
 

Thanks everyone. That is one large rear end to need that much fluid

I can only imagine how long it may have gone between being changed. A guy on the forum posted a link to a video of a truck like ours with a clear diff cover. It's amazing how much that fluid gets stirred around. It made me want to change my fluid
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Re: Rear differential oil
 

Could be like mine was as I dont think it had ever been changed and had as much water as it did oil, oh yeah mine burnt up on the 250 mile drive home... :(


I highly suggest changing all the fluids on something new to you when you get it home. Oh yeah my tranny had tanny fluid instead of gear oil like it should have and the power steering looked like oil..
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Re: Rear differential oil
 

What do you think of this stuff? Looks like one galon is almost exactly what I'll need. I think I'll skip doing synthetic. Way too expensive, where I'd need 4 of the quart sized bottles

http://www.autozone.com/autozone/acc...er=972913_0_0_
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Re: Rear differential oil
 

Looks like a winner to me.

Re: Rear differential oil
 

When I used to have a boat (B ring O ut A nother T housand), I had a cheap little pump that screws right on to the top of an oil bottle, it's for pumping the oil into the outdrive from the bottom up. Point is, the thing was like five bucks and it works really good for pumping oil into the diff. Marine West, down there on about 7200 So. State should have them. I think that's where it is. The one behind Inkley's closed down.

Re: Rear differential oil
 

I use one of those pumps too, they work great. As a former boat owner I can say the two best days of your life are the day you buy it, and the day you sell it.
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Re: Rear differential oil
 

thank goodness you changed your avatar scott... yikes, that other one was givin me the willys :lol:

mr. b - i agree with tim - valvoline 80W90 is perfect for this. I've used that and Pennzoil 80W90 also with no issues ever.

ditto on the pump, worth owning one just to avoid wearing an 80W90 suit. Hard to wash out of your eyebrows, ear and nose hair, especially when they're all about the same length...

Re: Rear differential oil
 

Just a word of advice....if it sounds like you're peeling out and there's no way you are, then you probably should check the lube level. I ran my first car out of grease and a couple days after that 'sweet' squealing sound stopped, the axle spiraled out of the rear end when I was taking a chick home. Seems that the bearings need that lube or they wear out, and squeal in agony.

Re: Rear differential oil
 

Great idea. Thanks.
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Re: Rear differential oil
 

I'd pull the cover to drain,clean,inspect,and see what gear ratio you have.

Re: Rear differential oil
 

2quarts is what fills a 12bolt rear// at leat that is what i've been puttin in for over 40years

if you can put 4quarts in a 12 bolt post a video

Re: Rear differential oil
 

I think Im gonna turn mine rear cover up and fill it totally up so Ill never have to check it again. lol Im glad you asked this Mister-B cause Im about to do the same to mine next week.

Re: Rear differential oil
 

Should be a Dana 60 with 4.10 gears.

Re: Rear differential oil
 

x2. This is a C/20

Re: Rear differential oil
 

Guys I need some quick help. I'm ready to do this, but can't locate the drain or fill plugs. I may have located one that's a square bolt on the back side, but I'm not sure about the fill hole?
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Re: Rear differential oil
 

Guys I need some quick help. I'm ready to do this, but can't locate the drain or fill plugs. I may have located one that's a square bolt on the back side, but I'm not sure about the fill hole?
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