Rear diff fluid change interval and capacity?

blackbetty14 · Sep 6, 2017

Coming up on 17k on my 14 CC 4x4, truck is almost 3 years Old (3 year lease up in DEC) and I got it with 240 miles on it. The truck is used as a daily, sees decent loads in the bed but haven't towed with it. Just recently picked up 2 motors and a tranny in the last 3 weeks. 4x4 is activated in winter regularly when we have snow which happens a good bit.

I was reading its good to swap the fluid at 15-20k by then most say 50k if you don't beat on it lol. I was going to upgrade the rear cover to a hytec cover or equal as I was going to do the fluid change so might as well get rid of the stock cover!

What are the thoughts on change interval and capacity? Thinking I might do valvoline synthetic 75w145 as we get temp swings from -10 to 0 in the winter and 100+ in the summer.

How much does the stock cover hold 2.5qts and the hytec holds how much 4qts?

HammerHead · Sep 7, 2017

I do my diffs and tranny at 30k.

Burla · Sep 7, 2017

the length of time between intervals is based on the fluid you choose. it isn't like an engine that keeps adding combustion contamination, you can have piece of mind over 100k miles if you choose ester gear fluid. Go to your local Oil Stop, they will tell you it doubles the interval, from 30k to 60k, but they are in the business to get you to change the fluid, you can actually go much longer.

stimpy433 · Sep 7, 2017

Are you going to buy the truck once your lease is up??? If not, I don't know why you'd bother with it since you'll be getting rid of it in a couple of months. Doesn't seem like you are really hard on your truck with a lot of heavy hauling or towing.

blackbetty14 · Sep 7, 2017

Thanks guys. The tranny is good for 100k no? I thought they were high like the spark plugs on the hemi.

I'll look into the ester oils. Best I got around me is autozone, advance, napa and pepboys. But I spend all my money on performance mail order items lol so getting oil shouldn't be an issue. Any recommendations? Are the aftermarket diff covers even worth it? Of course I like the look but at the same time the hytec doesn't even preload the caps like my moser does on my firebird.

I'm def keeping the truck lol. At this point they would be getting a ton of value on me bringing the truck back with 18k when it should have 30k. Plus I have way to many mods and I love the truck. Sure an 8spd would be nice and a nav but I don't "need" them. So the plan is the finance and hopefully owe less on the truck than it's worth and getting something else if I want to.

misuracaf10 · Sep 7, 2017

I heard with an ester base such as redline gear Oil You can double the change interval.. going from 15 k to like 30-50k with redline. I feel @burla will have an answer that is more accurate for us about this topic

Sent from my iPhone using Tapatalk

blackbetty14 · Sep 7, 2017

How much better is the redline compared to like valvoline synthetic? I don't mind changing it. Building fast cars is like my most favorite thing to do lol kind of an obsession. If I can use parts store valvoline at a good price and keep it in for 20k and swap it out then that's what I do. Don't want to spend $100 on redline and keep it in for 50k. It's not to say I won't tow more in the future, I just haven't had to thus far.

I'm very familiar with redline and have used the products, as well as Joe Gibbs, yards yadda basically all the huge companies except amsoil as my pockets aren't that deep lol.

I'm also a big fan more frequent changes vs super high mileage changes. With that being said I run penzoil platinum synth in the engine and a good filter and will still change the oil out at 8k even if it's good for 10k. My thinking is if it's got something in it I want it out, the longer it's in the more contentrated the contaminents are. Filters can only filter out so much and down to a certain size. The rear diff has no filter lol so I can only imagine what's in it with the 4x4 rear diff and factory gears wearing in.

Burla · Sep 7, 2017

The fluid in the 8 speeds can go 100k mile plus and farther and still be perfect. Ton of stuff out there on this, mainly because it is a PAO fluid. The 6 speed factory oil isn't 100k mile oil. This is a perfect example of comparing real synthetic fluid to a mineral fluid. BTW, that factory PAO for the 8 speed is literally 30 dollars a qrt. I will be doing my 30k tranny flush soon, so I will see forst hand what the oil looks like at 30.

If you like a short interval, then go for that. In our application likely that is all you need.
Just for your info... The reason why you need a short interval is because mineral oil breaks down with heat cycles and at high heat. Esters have many benefits in the gears, not only do they not break down the same under heat, but they stick to hot metal whereas mineral oil avoids hot metal, and many times can keep temps lower.

misuracaf10 · Sep 8, 2017

Burla said:
The fluid in the 8 speeds can go 100k mile plus and farther and still be perfect. Ton of stuff out there on this, mainly because it is a PAO fluid. The 6 speed factory oil isn't 100k mile oil. This is a perfect example of comparing real synthetic fluid to a mineral fluid. BTW, that factory PAO for the 8 speed is literally 30 dollars a qrt. I will be doing my 30k tranny flush soon, so I will see forst hand what the oil looks like at 30.

If you like a short interval, then go for that. In our application likely that is all you need.
Just for your info... The reason why you need a short interval is because mineral oil breaks down with heat cycles and at high heat. Esters have many benefits in the gears, not only do they not break down the same under heat, but they stick to hot metal whereas mineral oil avoids hot metal, and many times can keep temps lower.

So what do you think a good interval is for the rear diff with redline fluid?

Sent from my iPhone using Tapatalk

tantore · Sep 9, 2017

100k.

R.L.K. · Sep 9, 2017

Here's a couple links one for your 65RFE XSMN here , just go to post #1 and read from there

http://www.ramforum.com/showthread.php?t=89546

Some good discussion on oil change , pan change & filter changes .

Here's one on the differentials , again some good discussion on fluid changes and such , also just goto post #1 and read from there .

http://www.ramforum.com/showthread.php?t=84221

Hope this helps !

Sent from my SM-G900V using Tapatalk

huntergreen · Sep 9, 2017

misuracaf10 said:
So what do you think a good interval is for the rear diff with redline fluid?

Sent from my iPhone using Tapatalk

I can tell you that the diff fluid from the factory is synthetic. My rear diff on my 11 sport was changed at 18000 miles due to a recall. The fluid didn't look bad at all and very little metal particles inside. Tech less than he expected.

huntergreen · Sep 9, 2017

Bty way, I had my trans fluid changed at 50ooo miles on the 11. I let the dealer do it.

Rear diff fluid change interval and capacity?

blackbetty14

Senior Member

HammerHead

USMC 0313

Burla

Senior Member

stimpy433

Senior Member

blackbetty14

Senior Member

misuracaf10

Senior Member

blackbetty14

Senior Member

Burla

Senior Member

misuracaf10

Senior Member

tantore

Senior Member

R.L.K.

Senior Member

huntergreen

Senior Member

huntergreen

Senior Member

Similar threads

Latest posts

Staff online

Members online

Forum statistics

Share this page