Truck rear differential is too hot to touch.

[doojus]

I'd watch out putting synthetic in torsen style limited slips like the stock AAM one or a Truetrac. I installed a Truetrac in mine and found that Eaton strongly advises not to use Synthetic because it can interfere with the operation of the diff. The only reason I mention this is because I know the stock LSD is very similar in design to the Truetrac. Little info from bobistheoilguy forum:

"One reason Eaton does not want synthetics or slippery additives used with the Trutrac is that it affects the bias ratio of the limited slip. The gear type limited slips rely on a certain amount of gear friction to operate. If you reduce friction with various base oils or additives, it reduces the effectiveness of the unit to a degree. I've not heard of any noise issues using synthetics, but the Eaton guy would probably know better than me."


Direct from Eaton:


"Mr. Grant-
We appreciate your interest in our product.
We recommend that you use any good mineral based multi-weight gear oil. Synthetics are not recommended. While many people have used synthetics in Truetracs without issue, there have been times that synthetics have caused the unit to be very noisy. Additionally, many of our resellers do not recommend synthetics for high performance applications. In fact, most will void their warranty if synthetics are used."

 

[seafish]

Agree, Yes, I called today, $19 per quart for the Mopar synthetic. The front (4 x 4) uses the same. They look up your vin number because they have had changes. I wouldn't just get some GL 5 from autozone. Could be using the wrong stuff.

The AAM 11.5" rear axle/diff, it does NOT need any additives or "special lube" in order for it to pull or engage. The dealership was telling you that only so that you would spend $19/quart at their parts counter. The AAM limited split diff does not require additves because it use a torsional gears, not clutch packs, to engage and equalize torque. Unless something has changed that I am unaware of, the dealership is lying to you, as ANY GL5 spec 75/90w (or 75/140w for severe duty towing) will work in your differential. They look up your vin number because that way they do not need to hire very smart people to find what parts/fluids your truck needs.

 

[Mikestruck]

The AAM 11.5" rear axle/diff, it does NOT need any additives or "special lube" in order for it to pull or engage. The dealership was telling you that only so that you would spend $19/quart at their parts counter. The AAM limited split diff does not require additves because it use a torsional gears, not clutch packs, to engage and equalize torque. Unless something has changed that I am unaware of, the dealership is lying to you, as ANY GL5 spec 75/90w (or 75/140w for severe duty towing) will work in your differential. They look up your vin number because that way they do not need to hire very smart people to find what parts/fluids your truck needs.

So I can put a 75/140 oil in my diffs. My 2012 Dodge Ram 3500 has no additives in the diffs? Just as long as I don't use synthetics.
Michael Avant

 

[Camperman]

So I can put a 75/140 oil in my diffs. My 2012 Dodge Ram 3500 has no additives in the diffs? Just as long as I don't use synthetics.
Michael Avant

I copied & pasted this from Amsoil's web site. Many may use the heavier diff fluid, but I stayed with 75W90, Severe Gear Differential fluid.

If a vehicle manufacturer recommends a 75W-90 gear lube, may a 75W-140 be used?

Answer: No. In most cases, 75W-140 gear lube is too thick to be used in place of 75W-90. For modified or non-stock differentials where a higher viscosity gear lube may be desired, AMSOIL typically recommends 75W-110. Contact AMSOIL Technical Services for specific recommendations at (715) 399-TECH (8324) or -- email address removed --.

 

[sag2]

The AAM 11.5" rear axle/diff, it does NOT need any additives or "special lube" in order for it to pull or engage. The dealership was telling you that only so that you would spend $19/quart at their parts counter. The AAM limited split diff does not require additves because it use a torsional gears, not clutch packs, to engage and equalize torque. Unless something has changed that I am unaware of, the dealership is lying to you, as ANY GL5 spec 75/90w (or 75/140w for severe duty towing) will work in your differential. They look up your vin number because that way they do not need to hire very smart people to find what parts/fluids your truck needs.

This is the factory fill and required for service lube. The dealer advised you to use it because that is what the truck came with, and the required minimum quality lube you should be putting in the truck. You can go with non synthetic if you want because someone said it was OK, but Ram doesn't. The statement "no additives required" is correct, just high quality synthetic fluid.

235 AA (9.25) Front Axle

MOPAR® Synthetic Gear Lubricant SAE 75W-90

1 Quart - 05102232AA


267 AA (10.5) (ANTI-SPIN)

MOPAR® Synthetic Gear Lubricant SAE 75W-90

1 Quart - 05102232AA

5.28 Pints

2.5 Liters


4.64 Pints


292 AA (11.5) (ANTI-SPIN)

MOPAR® Synthetic Gear Lubricant SAE 75W-90

1 Quart - 05102232AA

8.45 Pints

4.0 Liters


2.2 Liters


310 RBI Rear Axle (ANTI-SPIN)

MOPAR® Synthetic Gear Lubricant SAE 75W-90

1 Quart - 05010320AA

13.94 Pints

6.6 Liters

 

[Too Tall]

Well, considering I'm on my 3rd rear end since the purchase in April, I'm going to stick with Mopar's recommendation for now. They told me 75W90 and the Mopar number is 68210057AA which supersedes all other fluids. That's for the front and rear end with limited slip. The transfer case take BW44-46.

 

[Ram4Sam]

Well, considering I'm on my 3rd rear end since the purchase in April, I'm going to stick with Mopar's recommendation for now. They told me 75W90 and the Mopar number is 68210057AA which supersedes all other fluids. That's for the front and rear end with limited slip. The transfer case take BW44-46.

Wow.......That is some kind of bad luck........You are making the right call here.

Sam

 

[cerberusiam]

You are making the right call here.

Or the wrong call depending on what is causing the failures.

There has to be way more to that many failures in that short of period than we are hearing about, but, as usual that would probably effectively debunk too many popular opinions requiring huge servings of crow. :-laf

If the the manufacturer keeps replacing then it is a consideration to use the recommended fluided. Depends on the individual pain threshold.

MOPAR® Synthetic Gear Lubricant SAE 75W-90

Dodge doesn't blend and bottle its own fluids. They are genarally too cheap to pay for any special formulation, they just spec it and somebody blends it. Just like ATF+4 you will be able to buy it under a generic or different name than Mopar for a lot less. Just have to figure out who the supplier is and what their store brand is.

 

[Too Tall]

Wow.......That is some kind of bad luck........You are making the right call here.

Sam

Yes, I'm staying with Mopar just to be safe. My dealer's prices are very reasonable. Oil filters are $11.39. (that's less than Walmart).

 

[jus2shy]

Here's a page out of the owner's manual for the curious. I recently changed my rear cover and was curious about how my gears were meshing and how much metal was in my diff floating around. Let's just say that I will check the plug with each oil change going forward and I added a magnet to the top of my diff to hopefully capture more debris as well. I loaded my diff up with Valvoline Synthetic 75W-90 with an SAE GL-5 rating.
#ad

 

[sag2]

Well, considering I'm on my 3rd rear end since the purchase in April, I'm going to stick with Mopar's recommendation for now. They told me 75W90 and the Mopar number is 68210057AA which supersedes all other fluids. That's for the front and rear end with limited slip. The transfer case take BW44-46.

Are you towing right out of the gate with them?

 

[Too Tall]

Are you towing right out of the gate with them?

The first failure occurred with about 1500 on it when I was on a camping trip to Arkansas towing 5K. The second failure at about 2200. Had driven around town and highway for a few hundred miles. It failed when I started towing. So this one has about 700 miles on it and I'm headed for Florida this week. We'll see. I'll try to do the 200 miles of 50 mpg

 

[sag2]

No wonder you are burning them up. They need to break in without towing for at least 500 miles. Some get lucky, but some don't.

 

[Too Tall]

No wonder you are burning them up. They need to break in without towing for at least 500 miles. Some get lucky, but some don't.

So I had 1500 and 700 before towing, that's not enough? The manual only says 500? Why am I burning them up. I've got about 800 on this one and getting ready to pull that big old 5K trailer again, what do you recommend I do?

 

[Ram4Sam]

Out of curiosity, what is happening to them...........

Sam

 

[Too Tall]

The 1st one which was the original started howling loudly. I brought it in and they ordered a ring and pinion and bearings and replaced them. Then after braking in the second set of gears I headed out for a 4200 mile trip. Started howling again. I'm quiet confident the dealer installed set was more of mechanic incompetence rather than any parts issue. So the dealer said they will order a new ring and pinion and bearings but this time they are going to add a shim. I asked if they checked the ring and pinion mesh pattern when they install the ring and pinion and they said, "no. we just put the parts in. but, we talked to Chrysler and they told us to put a shim in this time." So I knew the dealer didn't have the expertise to set the ring and pinion if they had to ask Chrysler and they were going to install a shim even before the checked the mesh pattern. I put together a chronological list of the down time this issue had caused and explained that another ring and pinion install was unexceptionable because, no offense but I didn't feel I'd come away with a truck that was as reliable as the new truck this is.

I told them my first choice was a new rear end, complete. Rotor to Rotor. 2nd, buy back my truck. Chrysler got back with the dealer and said, "that sounded reasonable". So after another 6 weeks, I'm riding on the 3rd and hopefully the last.

700 miles on it and I'll be leaving for Florida Wed. Hopefully, my luck will improve. As far sag2's comment, he must have misunderstood, because all three sets of gears have more than 500 miles before I towed any thing. Frankly, I've never heard of burning up a set of gears from not being broken in. I'd like to know who actually brakes in gears. But I did any way. They also say to not tow at more than 50 mph for the first 200 miles. That's going to be hard to do on I 10 and my wife will get cabin fever aweful fast but I'll try. I'm only towing 5000 lbs.

 

[DonFitzwater]

So I don't understand what was done last.....did they rebuild it a third time or did they install an axle assembly?

 

[Too Tall]

So I don't understand what was done last.....did they rebuild it a third time or did they install an axle assembly?

Sorry for the rambling. So the 3rd one is entire new axle assemble. It came with everything including new rotors.

 

[gsbrockman]

When I purchased my '13 RAM 3500 Crew Cab 4x4 DRW, I drove off the lot at 13 miles with about 2900 lbs behind it. Sure.....2900 lbs is no huge amount of weight, but towing right out of the box is not hard on these trucks IMO.
#ad


When I purchased my '14 RAM 3500 Crew Cab 4x4 DRW, two days and 260 miles later, I had a 10k 40 ft GatorMade gooseneck trailer behind it going from Somerset, KY to Mt Pleasant, TX. Again......no problems.
#ad


Maybe some have better luck than others....

 

[Bob V]

I do believe that the second set of gears failed either by improper install or possibly a defective housing. I would bet that the housing is (was) defective. Did the rear end howl all the time, or when accelerating, or when decelerating?