Check your rear diff fluid level

[Bw1605]

Owner's manual is pretty good about the weight per configuration-several variations. Your window sticker or build sheet should have gear ratio and whether or not it is a limited slip diff. Amsoil page is pretty good about capacity as well.

Build sheet states anti spin rear differential , no mention of limited slip.

 

[BowDown]

Build sheet states anti spin rear differential , no mention of limited slip.

Anti spin is limited slip

 

[Bw1605]

Anti spin is limited slip

Well, that changes everything. Thanks for that

 

[1D32319]

Well, that changes everything. Thanks for that

So it sounds like you have exactly what I have. 3.92 with limited slip and no max tow.

I ordered 3 quarts of 75W140
1 Quart of 75W90
1 4ounce bottle of Mopar limited slip juice. Nice little gotcha from Mopar when the specs call for 5 ounces.

The actual capacity is aprox 2.3 pints in the front, 5.7 pints in the rear, and calls for 5 ounces of Mopar's juice.

I'll do 4 ounces of LS juice in the rear(close enough when you consider many synthetics are already compatible with LS diffs), and then fill with 75W140.

In the front, I'll fill with 75W90 and top off with 75W140--no way was I going to buy an extra quart of 75W90 for just 0.3 pints.

The Amsoil squeezable quarts are awesome. I notice Valvoline has upped their game and offered squeezable quarts as well.

 

[BowDown]

I did mine about a month ago, put 3 1 quart bottles of Mobil 1 75/90w and was done. M1 already has the additive in it.
Mobil 1 needs to get with the squeezable quarts because that's the S, the plastic bottles are worthless upside down and under the truck . I didn't do 75/140 as my truck doesn't call for it and I may tow 5 times a year

 

[c3k]

Squeezable quarts...

Yeah, I wish I had some. Instead, I paid another 8 bucks for narrow-top quart pump. Sigh. It'll go in my kit...

 

[1D32319]

So with a total of both differential's factory spec capacity of 8 pints>AKA 4 quarts>AKA 1 gallon, this is what drained. This gallon jug also has about 4 ounces of fresh oil as the Mopar LS juice took up 4 ounces of room in the rear diff. I used extra "tricks" to ensure I got as much of a drain as possible.

Rear: Drain level for 30 minutes, jack up right side for 30 minutes, jack up left side for 30 minutes, another 20 minutes draining level. Each extra step brought a trickle or more out.
Front: Drain level for 30 minutes, jack up rear for 30 minutes.

OEM fill is definitely dino in the rear, likely dino in the front(not old enough to tell and the smell from the rear overpowered the front.

Over than the truck being stupid low to the ground, it is as straightforward as it should be. Front diff needs 8mm hex, rear diff needs a 14 and an 8mm hex. Mopar LS juice won't easily go in the fill, so I just added it to the first quart of 75W140 going into the rear.

IMO, it is likely safe to say it wasn't full from the factory.

 

[Mopar_maxi]

Drained and filled mine with 75-140 redline. I filled like I always have, until it slowly runs out of the fill hole.

 

[wallyuwl]

I will probably change both at 20k, which should be next summer.

Was planning to use Amsoil 75w-110 in the rear. But was in Advance Auto yesterday and they had a sticker on the shelf for Synpower in the squeeze pouch, 2 for $8. That is $11 off per quart. It was supposed to be $8 off two but the sign was wrong. I bought 6 quarts of 75w-90 (after which they took the tag down), but may exchange one at Walmart for a 75w-140, which would make the rear approx 75w-110 or 112 since it takes a bit less than 3 qts.

 

[Bw1605]

So it sounds like you have exactly what I have. 3.92 with limited slip and no max tow.

I ordered 3 quarts of 75W140
1 Quart of 75W90
1 4ounce bottle of Mopar limited slip juice. Nice little gotcha from Mopar when the specs call for 5 ounces.

The actual capacity is aprox 2.3 pints in the front, 5.7 pints in the rear, and calls for 5 ounces of Mopar's juice.

I'll do 4 ounces of LS juice in the rear(close enough when you consider many synthetics are already compatible with LS diffs), and then fill with 75W140.

In the front, I'll fill with 75W90 and top off with 75W140--no way was I going to buy an extra quart of 75W90 for just 0.3 pints.

The Amsoil squeezable quarts are awesome. I notice Valvoline has upped their game and offered squeezable quarts as well.

So it sounds like you have exactly what I have. 3.92 with limited slip and no max tow.

I ordered 3 quarts of 75W140
1 Quart of 75W90
1 4ounce bottle of Mopar limited slip juice. Nice little gotcha from Mopar when the specs call for 5 ounces.

The actual capacity is aprox 2.3 pints in the front, 5.7 pints in the rear, and calls for 5 ounces of Mopar's juice.

I'll do 4 ounces of LS juice in the rear(close enough when you consider many synthetics are already compatible with LS diffs), and then fill with 75W140.

In the front, I'll fill with 75W90 and top off with 75W140--no way was I going to buy an extra quart of 75W90 for just 0.3 pints.

The Amsoil squeezable quarts are awesome. I notice Valvoline has upped their game and offered squeezable quarts as well.

Yep, same rear end. I usually use Amsoil and change the differentials at around 40,000 but this truck has been used for towing a 28 foot travel trailer since it was broken in. Time to take care of it a little sooner. Transmission fluid will still be around 70 to 80,000 miles ago. I have 32k on it. Not sure why Amsoil want you to use Mopar‘s Limited slip stuff but I will. I just thought Amsoil had their own limited slip stuff.

 

[Bw1605]

I will probably change both at 20k, which should be next summer.

Was planning to use Amsoil 75w-110 in the rear. But was in Advance Auto yesterday and they had a sticker on the shelf for Synpower in the squeeze pouch, 2 for $8. That is $11 off per quart. It was supposed to be $8 off two but the sign was wrong. I bought 6 quarts of 75w-90 (after which they took the tag down), but may exchange one at Walmart for a 75w-140, which would make the rear approx 75w-110 or 112 since it takes a bit less than 3 qts.

Yea but I will pay the extra for Amsoil. Ive seen situations where it made my Harley run better and kept an older engine in an old car I had run like new. Worth the extra money In the long run, to me at least

 

[1D32319]

Yep, same rear end. I usually use Amsoil and change the differentials at around 40,000 but this truck has been used for towing a 28 foot travel trailer since it was broken. Time to take care of it a little sooner. Transmission fluid will still be around 70 to 80,000 miles ago. I have 32k on it. Not sure why Amsoil want you to use Mopar‘s Limited slip stuff but I will. I just thought Amsoil had their own limited slip stuff.

Had the same thought on the limited slip additive. Amsoil makes their own AND their gear oil already contains some. I complied with Amsoil's recommendations though. Well, sort of-I only bought one 4 ounce bottle of Mopar LS additive.

Yea but I will pay the extra for Amsoil. Ive seen situations where it made my Harley run better and kept an older engine in an old car I had run like new. Worth the extra money In the long run, to me at least

It's overkill, but I'm a firm believer of using Amsoil gear oil. I know I would be just fine with Mobil 1 or Valvoline as well. This is something I may change once every 75-100K miles, and I want the "best". Best in quotes for a reason as it is subjective until it is tested by independent labs. I may not be a huge fan of Amsoil's marketing and often refer to them as Scamsoil because of it, but there is no arguing that they produce quality products.

For other boxes(engine, etc), I'll use less expensive lubricants.

 

[c3k]

Just drained the front and rear diffs. Truck has 5,800 miles. Yeah...way early.

"Old" fluid in bucket with new fluid in hose in front to compare color.



x

 

[c3k]

...and, after most of the fluid was out of the rear, I put a magnet into the case through the drain hole and swept it around.

I got some small metal swarf, like graphite-fine, and it took ~a dozen sweeps to get it all out. But, no chunks and now I know my rear diff is fill to the drain plug. (That magnet is about 3/4" in diameter: it barely fit into the drain hole.)

I drained the front diff, as well. I don't know how far I've driven with the front drive engaged, but it's not much. Surely less than 100 miles, probably about 20? As expected, front fluid looked bottle-fresh. But, again, now I know that my front diff is filled to the correct level.

 

[1D32319]

Just drained the front and rear diffs. Truck has 5,800 miles. Yeah...way early.

You beat me-7206 when I did it above.

I may be early, but I like knowing what is in there and that it is filled to the proper level.

 

[pcar]

I just checked mine. It was low. I've got 11k on the truck, 8.5k of that was towing my traving trailer. I topped it off with a little over a half quart before it started to overflow. I'll be doing a complete change with Redline next spring before i start dragging the trailer again. 0.6 qts doesn't sound like alot but thats just about 20% of the full capacity. RAM dropped the ball with this.

 

[GKIII]

I just changed my rear fluid out (to get the break-in particles out). Checked the fluid level before I drained, and it was a solid 1.5 inches below the fill port.

Pulled the cover, flushed it out, there was A LOT of fine metallic material coming out. Like...a surprising amount. I could have scooped some of that stuff out with a spoon if I wanted.

Either way, changed to redline 75W-90 and filled to the proper level. Just based on the fact that it was low I'm glad I did the change at ~7200 miles.

 

[Scram1500]

I just changed my rear fluid out (to get the break-in particles out). Checked the fluid level before I drained, and it was a solid 1.5 inches below the fill port.

Pulled the cover, flushed it out, there was A LOT of fine metallic material coming out. Like...a surprising amount. I could have scooped some of that stuff out with a spoon if I wanted.

Either way, changed to redline 75W-90 and filled to the proper level. Just based on the fact that it was low I'm glad I did the change at ~7200 miles.

What did you for the gasket?

 

[GKIII]

What did you for the gasket?

I used a Lubelocker 9.25" gasket (LLR-C925). They work great, been using them on other vehicles for years.

 

[2021QCBH]

Happy to report, front/rear diffs completely full as well as my transfer case. I thought the rear was slightly low so I picked up a quart of Mopar synthetic. As soon as I squeezed some in it came right back out the fill hole.