Why change differential fluid so often?

[callbay]

My son has a 4x4 5500 Dodge that is really a 2 ton pickup. Everything is extra heavy duty.

The manual says to change the front and rear differential fluid every 15,000 miles.

That seems very often to me and I wondered why this is needed?

Thanks!

 

[turtlevette]

There's probably some design deficiency they're trying to compensate for. In practice diffs don't get any attention unless they've been under water.

 

[HTSS_TR]

I think the maintenance schedule is based on worse case scenario, max towing capacity and climbing steep hill(s).

If the Dodge is rarely tow anything and it is out of power-train warranty then you may be able to extend fluid exchange to 30k miles, provided that you use high quality gear fluid.

 

[AandPDan]

The rear is likely a limited slip. Clutch material accumulates in the fluid and needs to be removed.

 

[eljefino]

Originally Posted By: turtlevette
There's probably some design deficiency they're trying to compensate for. In practice diffs don't get any attention unless they've been under water.



This times a bunch. I wonder how many of these plow snow and get wrecked doing so.

 

[The motor guy]

Originally Posted By: callbay
My son has a 4x4 5500 Dodge that is really a 2 ton pickup. Everything is extra heavy duty.

The manual says to change the front and rear differential fluid every 15,000 miles.

That seems very often to me and I wondered why this is needed?

Thanks!


Interesting! This must just be a dodge thing then cause I don't believe the 5500 models have an American axle. They have a much bigger rear differential. The 2500-3500 models have the 11.5 American axle which call for 15,000 mile oil changes. Chevrolet uses the same rear end which has a much longer oil change interval, although I never found out what it was.

 

[stchman]

I guess they figure a 5500 is going to work REALLY hard for a living.

You might be able to go 30K if you use some Amsoil Severe Gear.

I bet the rear diff on that 5500 hold about 6 quarts of gear oil.

 

[Ramblejam]

Ram 5500 is a Dana S111.

Per the axle manufacturer:

 

[raytseng]

does it really say change? Or does it say "inspect and replace" just to make sure the fluid level is right.

 

[Kawiguy454]

Oversize tires + towing + limited slip = heavy duty.

I would use heavy synthetic like M1 75-140

 

[mjoekingz28]

Maybe a candidate for a gear oil analysis.

 

[mjoekingz28]

What is the difference between the synthetics Ramblejam?

One is double the interval of the other.

 

[Ramblejam]

* Axles using LMS wheel end system
** Axles using adjustable wheel bearing system

 

[dailydriver]

Originally Posted By: AandPDan
The rear is likely a limited slip. Clutch material accumulates in the fluid and needs to be removed.


^^^THIS, and for the reason that my car's rear axle ring and pinion are WAY TOO SMALL, and too highly stressed, for the power/torque output of this engine, are why I change mine out "too frequently".

I fear MASSIVE shear going on because of this (even with the best fluids out there!), and change it so often it would make the penny pinchers on here CRINGE in agony!

 

[Ramblejam]

Originally Posted By: dailydriver
Originally Posted By: AandPDan
The rear is likely a limited slip. Clutch material accumulates in the fluid and needs to be removed.


^^^THIS, and for the reason that my car's rear axle ring and pinion are WAY TOO SMALL, and too highly stressed, for the power/torque output of this engine, are why I change mine out "too frequently".

I fear MASSIVE shear going on because of this (even with the best fluids out there!), and change it so often it would make the penny pinchers on here CRINGE in agony!


What if I told you two that the limited slip here is a Truetrac...

 

[dailydriver]

^^^IF it was a highly stressed ring and pinion (too small for the power output of the engine), along with the possible shearing caused by the worm gears/side gears/etc. of the Truetrac, I might still change it more than the manual calls for, even without the carbon, or steel, 'fines' from the clutch packs.

 

[willyreid]

Delo Gear ESI 75w/140 especially if you are going to be changing it every 15,000 miles

 

[Ramblejam]

Originally Posted By: dailydriver
^^^IF it was a highly stressed ring and pinion (too small for the power output of the engine), along with the possible shearing caused by the worm gears/side gears/etc. of the Truetrac, I might still change it more than the manual calls for, even without the carbon, or steel, 'fines' from the clutch packs.


11.8" gear, 1.57" shafts, and 16 pint oil capacity. Still want to change it so frequently?

 

[dailydriver]

Originally Posted By: Ramblejam
Originally Posted By: dailydriver
^^^IF it was a highly stressed ring and pinion (too small for the power output of the engine), along with the possible shearing caused by the worm gears/side gears/etc. of the Truetrac, I might still change it more than the manual calls for, even without the carbon, or steel, 'fines' from the clutch packs.


11.8" gear, 1.57" shafts, and 16 pint oil capacity. Still want to change it so frequently?


NOPE, but that is why I put the "highly stressed" disclaimer in that post.

(MY rear axle's capacity is only 2 quarts as well.)

 

[Joel_MD]

My 2007 Dodge 2500 calls for 15,000 mile changes for the differentials too. The rear is a AAM 11.5", not sure what the front is. I changed the gear oil in both axles at 15k using Amsoil Severe Gear 75W-90 and left it in for about 70k miles/six years. The oil drained out looking pretty good. The magnetic drain plug had a slight layer of iron particles, about what you'd expect. I don't see any reason to change the gear oil at the 15k-mile factory specified interval unless you're towing really heavy, which a lot of Dodge guys do.

Here's a DIY thread I created at the Cummins Forum in case anybody is interested: http://www.cumminsforum.com/forum/07-5-0...nge-w-pics.html