4X4 RAM 3500HD Differential Lube change Question

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Hey guys and what few gals we have here...

So RAM recommends I change the differential fluid in my 2014 RAM 3500HD every 15,000 miles if towing frequently. I do nothing but towing freight with the beast, and have been following the maintenance schedule until one day, the light bulb goes off in my head...
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My question is, since I NEVER engage the front axle and only drive with the dually's doing all the work, is it really necessary to change the oil in the front axle? I mean, sure the gears are spinning since the front tires are rolling but they aren't getting any LOAD, unlike the read axle does. Why on earth would RAM suggest I dump perfectly good oil from the front axle every 15k miles? It doesn't make any sense to me.
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The last time I changed the fluid, the rear axle lube looked a bit darker then it went in and was loaded with metallic bits floating in it, the front looked clean as the day it went in! with not much metal in the oil.

Who else thinks that Chrysler is out to get my money and nothing more with this absurd maintenance schedule for the front axle, which isn't even in use!!
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I recently changed the rear axle lube on schedule but decided to go 2x the distance before changing the front axle's lube.

Who else feels I'm perfectly fine doing so? Depending on how the fluid will look after 30k miles, I'm thinking of extending the oil change interval even further, to save money.

Thoughts, comments?
 
My thoughts are that the best time to change the fluid is early in its life to drain out the early wear in and contamination if any exists. After that the intervals can probably be extended.

You were obviously able to see the wear metals in the rear so that's a good thing you got that out of there.

Have you considered upgrading to something like redline gear oils?
 
I think you'll be fine, but I'm just guessing really. You can do a UOA on the front differential gear oil when you take it out after 30k to confirm you aren't running it too long. At least then you'll know you're good to go for 30k miles.
 
Originally Posted By: 901Memphis
My thoughts are that the best time to change the fluid is early in its life to drain out the early wear in and contamination if any exists. After that the intervals can probably be extended.

You were obviously able to see the wear metals in the rear so that's a good thing you got that out of there.

Have you considered upgrading to something like redline gear oils?


The OEM Mopar axle lube is 75w85 Synthetic, so "upgrading" to Redline Oil's synthetic gear lube will benefit me how?

Plus I can get the Mopar lube cheaper anyway.
 
I have 2wd but in my opinion if you don't use the 4wd I would just change it after a 1000 miles or so and then never worry about changing the front again. The gears still spin but their isn't any load on them so it's not like you're generating much heat and wearing out the fluid. The 15,000 mile change interval is [censored]. I put amsoil in mine and changed it a second time after 15,000 miles and it looked exactly the same as the new stuff. I would think 50,000 miles would be more realistic honestly. That's what I'm going to do.
 
Originally Posted By: abycat
my guess is the front diff still has spinning parts when it's not engaged so it still wears the fluid. Just my guess.


Oh I'm positive that the gears inside are spinning, even though it's not engaged and doesn't transfer any power to the wheels. I just can't imagine this fluid wearing out within 15k miles...
 
Originally Posted By: Artem
Originally Posted By: abycat
my guess is the front diff still has spinning parts when it's not engaged so it still wears the fluid. Just my guess.


Oh I'm positive that the gears inside are spinning, even though it's not engaged and doesn't transfer any power to the wheels. I just can't imagine this fluid wearing out within 15k miles...


that does sound pretty extreme. my t case is the same. It has spinning parts when in 4 or 2 wheel
 
Originally Posted By: abycat
Originally Posted By: Artem
Originally Posted By: abycat
my guess is the front diff still has spinning parts when it's not engaged so it still wears the fluid. Just my guess.


Oh I'm positive that the gears inside are spinning, even though it's not engaged and doesn't transfer any power to the wheels. I just can't imagine this fluid wearing out within 15k miles...


that does sound pretty extreme. my t case is the same. It has spinning parts when in 4 or 2 wheel


Ram calls for the Transfer Case oil change @ 60k miles and it holds a pathetic 2 quarts.

I don't know what's up with these axles though but I feel it's a bit excessive to be unbolting the axle covers every 15k miles (every few months for me).

Now if they designed an easy drain bolt into the pan, I probably wouldn't complain as much but these idiots didn't do so and I have to deal with a messy oil change.
 
Originally Posted By: Artem
Originally Posted By: abycat
my guess is the front diff still has spinning parts when it's not engaged so it still wears the fluid. Just my guess.


Oh I'm positive that the gears inside are spinning, even though it's not engaged and doesn't transfer any power to the wheels. I just can't imagine this fluid wearing out within 15k miles...


Its not. I'd change the rear axle according to schedule, and do the front maybe ever 3rd or 4th rear axle change.

Also I agree with the people who advise an "early" change. I just did the rear axle fluid in my SRT at 30k miles, and it was pretty full of "break-in stuff." The magnetic drain plug had grabbed all the metallic powder, but the fluid was opaque most likely from the limited-slip clutch packs seating. Made me wish I'd done a fresh fill at about 10k. I'll be doing it every 30k from now on, mostly for the benefit of those clutch packs.
 
Originally Posted By: Artem

I don't know what's up with these axles though but I feel it's a bit excessive to be unbolting the axle covers every 15k miles (every few months for me).

Now if they designed an easy drain bolt into the pan, I probably wouldn't complain as much but these idiots didn't do so and I have to deal with a messy oil change.


Blame American Axle for that feature (although Dana and everyone else do exactly the same thing with solid axle diffs... But seriously, get a $12 suction gun and pull the old fluid out the fill hole. You can get 90% of it, and with frequent changes that's good enough- I've been doing it that way on my vintage solid-axle cars for decades.

The SRT and wife's JGC both have nice drain plugs... although the JGC's is almost completely blocked by the exhaust pipe so its really hard to get the allen-head driver in it :-/
 
Originally Posted By: Artem
Originally Posted By: 901Memphis
My thoughts are that the best time to change the fluid is early in its life to drain out the early wear in and contamination if any exists. After that the intervals can probably be extended.

You were obviously able to see the wear metals in the rear so that's a good thing you got that out of there.

Have you considered upgrading to something like redline gear oils?


The OEM Mopar axle lube is 75w85 Synthetic, so "upgrading" to Redline Oil's synthetic gear lube will benefit me how?

Plus I can get the Mopar lube cheaper anyway.
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From my being around its my understanding that Redline gear oils are about the best in the business, they use esters in their oil whereas the oem fluid maybe be a mostly group 3 blend, the Redline should offer extra protection against extended intervals, especially once you get the break in material out.

I can't imagine that the oem fluid is using esters, but it's possible, a look at the PDS might reveal something but I'm on my phone now.
 
Oh I agree that Redline's lube is awesome but unless I can find it for around $15 a quart shipped or picked up, I'll stick to Mopar. Dumping it so frequently = fresh lube in there constantly. I'm happy with that.
 
I would change the front diff every 45k or 60k, after the initial 15k change.

I'd also consider a synth 75w90 which opens up more fluid choices. How much extra MPG do you get with the eco-thin 75w85?
 
Hey Artem, I'll let you pick a number but I would absolutely extend the front diff interval. Ok...I'll say at least double what you've been doing.

The rear diff housing looks ginormous on those trucks. How much gear oil does it take?
 
Who knows regarding the MPG. I can't see the extra w05 hurting MPGs THAT much but I also don't see any reason to change from Mopar's synthetic lube either. I don't see any other full synthetic for less then $15 a quart.

My main question wasn't about changing fluid type or about how much it costs per quart. My question was regarding the SEVERE service oil change recommendation for the front axle, which doesn't get any load, and just spins freely for 15k miles. Why would I change that oil after 15k miles when the axle didn't get any load, unlike the rear axle, which receives 850LB of torque and pulls 30,000 pounds of weight... doesn't make any sense to me.

I agree with you guys who suggested extending the front axle's oil change interval. I dumped the initial fill @ 15k as recommended but haven't touched the front axle since, now also 40k on the clock (25k since last oil change).

I'll dump it after 40k miles of use, to see how it looks.
 
You could always send it in for a UOA with TAN to see how it's doing...It will give you some entertainment and possibly save you money if you find out you can extend much further with low wear.
 
Yea I'm not interested in getting a UOA done. I'll just extend based solely on the way the front lube looks, compared to the rear axle's lube.
 
I always found this rather mysterious as well. Not only does the front axle not take any drive power under 2WD tow, but the wheel bearings are separate from the axle housing. The bearings in the axle don't carry the load, so the lube isn't affected by that.

I've chosen to err on the side of caution, though, and change my front axle fluid along with the rear. Our axles are in high demand by the rock crawling crowd, and are not cheap to replace. I'd rather pay the extra for the fluid, than service the front axle.

I've been meaning to do a UOA. I'm 2500 miles from next service. Time to find out what shape it will be in at that point.
 
Not to give any advice, but I have a 2005 2500 4x4 that spends most of its time towing our 28 ft camper. Had vehicle since new and at 15000 miles rear factory lube (Mopar 75w-90) looked like grey paint. Second change just as bad. Went with 75w-140 and gear oil looks fresh at every change. If just using for driving with little towing 75w-90 is ok but for heavy towing use the thicker gear oil (75w-140) Much less metal in oil.
 
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