Diff fluid

dapepper9 · Feb 26, 2014

Tomorrow I'm changing out the fluid in my front diff (its pre horrible) and was just wondering about the fluid. My Haynes says to use 90W GL-5 gear oil. My question here is dad has a bottle of gear oil in the garage but its says 80W-90 GL-5, is this ok or should I buy specific 90W?

dodge dude94 · Feb 26, 2014

Should work, it's just thinner when it's cold, which might not be a bad thing.

dapepper9 · Feb 26, 2014

cool, wanted to be sure

dodge dude94 · Feb 26, 2014

On second thought, the 01 FSM specifies 75W140. Hmm...that's the same oil that's specified for the rear axle for HD use, while normal usage for the rear axle is 80W90. Interesting...

Brakelate · Feb 26, 2014

Dodge Dude is always spot on with his info.

But, for a higher mileage truck, in the front diff, I wouldn't sweat it. The price is right and it is right there in your hand.

Worse comes to worse, drive it around with the fresh lighter fluid in there, and if it seems to sound funny, swap it out later. If there is that much sludge in there, it wouldn't hurt to do a "flush" by dumping the 80-90 back out and putting in the wider / higher range stuff after a week or so.

If it were me, I would just fill it with what you have and speed on! :driver:

dapepper9 · Feb 26, 2014

cool, even if what I have isn't quite right I guarantee its better than what's in it lol, I'll post pics tomorrow night after I do it to show ya what I mean

dodge dude94 · Feb 26, 2014

If it's as bad as you say it is, make sure you clean everything really well. lol Usually the front axle can go longer than the rear since it's not under power all the time.

Sparkyy · Feb 26, 2014

I believe the rear diff on mine calls for 75w-140 and the service tech at my dealership said to just use both in front and rear which I did. Others online have said the same thing.

The front is something lighter in weight but this way, if ever need to, I won't have to worry about the oil in the front diff when towing in 4x4.

Just my 2cents.

Merc225hp · Feb 26, 2014

Op what you have on hand will work just fine in the front diff.

Brakelate · Feb 26, 2014

Completely off topic, but Dapepper9 you sure have a cool Sig pic and Personal Profile Page. Makes me want to go tinker with mine.

dapepper9 · Feb 26, 2014

Thx Brakelate lol, sig pic is one of my senior pics (looks great cuz where I'm at hides the rocker rust, and i just got bored one day in class with the profile :badger_1:

dapepper9 · Feb 26, 2014

dodge dude94 said:
If it's as bad as you say it is, make sure you clean everything really well. lol Usually the front axle can go longer than the rear since it's not under power all the time.

Ya, Imma lil worried that the gears are damaged and might need replaced, 4x4 was working before I checked tho so I'm assuming still works (not willing to engage yet) so gonna inspect when I'm in there

smiley · Feb 27, 2014

I would just suggest you get the synthetic whether you go with 75w-90 or 75w-140. I would do the 75w-140 if I were you because it will be best protection when it gets really hot and towing. I am stuck with 75w-90 because if Auburn but it has not been an issue so far.

$miley

dodge dude94 · Feb 27, 2014

dapepper9 said:
Ya, Imma lil worried that the gears are damaged and might need replaced, 4x4 was working before I checked tho so I'm assuming still works (not willing to engage yet) so gonna inspect when I'm in there

Oh, you'll know if it's damaged. If you aren't getting any weird noises or behavior from the diff, it's fine. Folks have been known to leave diff fluid unchecked for decades with no issues.

Granted, that doesn't mean it's right.

smiley · Feb 27, 2014

So true

$miley

dodge dude94 · Feb 27, 2014

Hell, I can't even get my diff plug off my rear! lol

Sparkyy · Feb 28, 2014

dodge dude94 said:
Hell, I can't even get my diff plug off my rear! lol

I'm assuming you have a rubber plug on the diffs? Seems the 1500s have that and the 2500s up have a bolt that plugs it.

Why not just remove the diff and pop it out from the inside?

dapepper9 · Feb 28, 2014

wow, that took alot longer than it should have lol, only got 1 pic (will post tonight) because I'm kinda one track minded :hands:

glad i did it tho, used some gasket sealer plus a felpro, biggest problem is the tie rod being in the way, if I was smart i would pulled it off and replaced it with the NEW ONE I HAVE IN THE HOUSE :Stupid Me:

Edit: gears looked great actually, there was a lil bit of metal in the oil but the gears looked nearly brand new, thinking just regular wear

Slidder · Feb 28, 2014

dapepper9 said:
Tomorrow I'm changing out the fluid in my front diff (its pre horrible) and was just wondering about the fluid. My Haynes says to use 90W GL-5 gear oil. My question here is dad has a bottle of gear oil in the garage but its says 80W-90 GL-5, is this ok or should I buy specific 90W?

I have owned so many different Dodge trucks, it's hard to remember the exact number. However, one thing I quickly learned when it comes to fluids in our trucks ~ stick with what the manufacture states in the owners manual.
I know this has been a huge debate over the years but I'll stick with what the manufacture's engineers recommend. They designed everything.

Get all of your fluids analized by a professional company. They will tell you if there is any metal in it and if so, how bad the part is or could be. I've never had to replace any parts on my trucks that relied on fluids.

dodge dude94 · Feb 28, 2014

Sparkyy said:
I'm assuming you have a rubber plug on the diffs? Seems the 1500s have that and the 2500s up have a bolt that plugs it.

Why not just remove the diff and pop it out from the inside?

Because I don't want the mess of dropping the cover and would rather suck the **** out then pull the cover. lol Yes, I'm lazy and don't want to know what I find. lol

dapepper9 said:
wow, that took alot longer than it should have lol, only got 1 pic (will post tonight) because I'm kinda one track minded glad i did it tho, used some gasket sealer plus a felpro, biggest problem is the tie rod being in the way, if I was smart i would pulled it off and replaced it with the NEW ONE I HAVE IN THE HOUSE

Edit: gears looked great actually, there was a lil bit of metal in the oil but the gears looked nearly brand new, thinking just regular wear

Good to hear! :waytogo:

Diff fluid

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