I got the preventative maintenance bug up my backside this weekend and changed out the engine oil & filter, fuel filter, transmission fluid, transfer case fluid, and rear differential fluid. The transfer case and transmission fluid was still fairly good looking.

I have 27000 miles on the truck and the fluid in the differential was very discolored. I tow a 7000lb travel trailer about 5 times a year and otherwise is just a daily driver. I am very concerned about the color of the fluid and glad I changed it.

I suggest others change it soon if hasn't been previously changed.

 

I did mine at 30k and did it again at 50k, changed an axle seal was why. I changed my oil at 63,XXX and checked everything. The RP wan't purple no more but had more of a light gray tint to it.

 

Limited slip diff tends to discolor fluid quickly.

 

Plan to change all my fluids this week, ordered the filters on line.... Air, Oil, Fuel. I am sitting here waiting for UPS so I can get started

 

I think the factory gear oil that Dodge uses is cheap junk being I've read many post about the thin gray water looking gear oil that has come out of many 2005 an up differentials. When I changed my diff's the oil looked like gray 5 wt oil and the truck only had 9500 miles so was very glad I did not wait any longer to change them out. As thin as that gear oil was I'm surprised Dodge doesn't have a large number of gears burned up from using the gear oil they do.

 

yikes! after reading this post, I am about ready to head over to Napa and buy some gear lube for the diff! DBLR I can hardly believe your gear oil looked bad at only 9500 miles!!!! Without opening up a large can of worms and starting a flame session/war....... How many quarts do i need for '07 3500? Any brand considerations? I dont need a new gasket, do I?

 

I forget right now how many quarts but want to say 3 for the rear diff and like 2 1/2 for a front diff.
I changed mine at 16,000 and it was also very gray in color. I think it has a lot to do with the diff just breaking in. I use the Valvoline full synthetic 75w90. The towing I do is all 12k lbs or less. (mostly less)

 

rockcrawler, you used the same weight lube for both the front and rear diffs? I thought the rear had to be a higher weight?

 

I changed out my Rear diff fliod with 100 miles on my truck!!! I bought it at the dealer and changed it SAME DAY. Guess what..... Grey, nasty, WATER, whitish, CONTAMINATED fluid in there!!! I had read reports from other guys so I changed it out same day to AMSOIL...

 

2003 here. mine were changed 30,miles ago or so ago going to do it again soon when times let me work 12hour days 6days a week so dosn't leave much time to fix the dodge probbly why l have somany issues

 

Swapped out ALL the oils in my '07 couple weeks ago, about 12k mi on the truck. Trans and Tcase looked like new. Rear axle real grey, not burnt, front, not so bad. Now I know what's in it and won't touch anything for quite a while.

 

when you guys change the diff fluid, you take the covers completely off and clean the bottom of the "pumpkin"? Isn't there metal shards and fine metallic dust in there? Will pretty much any GL-5 rated syn gear lube work?

 

And to clean the cover and get a visual inspection on the gears and such.

 

and re-installing the cover is no prob? Gasket sealer req'd? or no? Sorry if too many questions, but I will be undertaking this in the next day or two, and want to make sure I have all my bases covered ahead of time.

talked to a buddy of mine who has a 1998 Ford F150 V8 auto, truck has 128k on it, he's never checked or changed the rear diff lube! So, we are going to do both of our trucks this weekend over at his house. This stuff stinks worse than bad coming out, right? Seems like a good idea to do it at his place! LOL

 

I installed an OASIS differential cover but reused the stock gasket even though Oasis supplied me with a tube of black RTV.

I think I would inspect the differential mating surface and the flatness of cover to ensure that everything will go back together. You should be fine reusing the stock gasket. The differential cover bolts have a torque spec of 30ftlbs. I'd go in a circle as you snug them up.