Differential oil change interval

[RJOL]

How often to you guys change your limited slip differential oil when you just tow a few times a year? Seem like doing it every 15,000 miles is overkill. Schedule "A" maintenance doesn't even give a mileage for changing it...

 

[Mactruck]

personal opinion

Personally, I would do the initial change around 10,000 miles. the OEM gear lube leaves alot to be desired. Replace it with a high quality synthetic lube, then change it whenever you feel comfortable. I believe DC recommends you change it every 30,000 miles and I believe that is accurate. Just not with the crap they put in our differentials.



Change it now and you'll be happy. I changed mine at 10,000 miles with Amsoils 75w-90 gear lube and a Mag-Hytec rear diff cover. The stuff that came out of my rear diff looked (and smelled) like crap. I have since put 5000 miles on with no discoloration of my differential lube. It's still nice and clear.



Also make sure you add a Limited slip modifier... .

 

[John Berger]

I agree

but I would go with Amsoil's Series 2000 75W-140 if you plan on towing and that's the weight DC recommends in the owner's manual. The 75W-90 will do the job, but with the temps I've seen in my differential while towing (230-240 degrees), the heavier weight lube will probably better serve you. Change it every 30K as well. I have a post you could do a search on that lists the oil analysis numbers on the Series 2000 75W-90 I ran in my differential for 42K miles. The numbers were good, but the recommendation was to change it out. I will definitely not run gear or transmission lube more than 30K ever again.

 

[KatDiesel]

Just changed my rearend fluid for the first time at 22,000 miles. The oil looked "used" but no metal, no discoloration or anything out of the ordinary. I don't tow but it had plenty of "burnouts" and hard driving on it. One of the bolts on the differential was "loose" tho, so that was the source of a little seeping. Now with the Mag-Hytec rearend cover on it looks awesome, too bad the rest of the axle doesn't look as good! I went with Amsoil 75w-90 since I don't tow a thing. Also changed the front fluid as well and that fluid looked damn near like it was new, it was clean, bu I changed it anyhow. Took 4 qts up front (Dana 60) and 5 qts on the rear Dana 70 with the Mag-Hytec cover.



Again if you tow, then the whole line of thinking changes.

 

[jkern]

i just checked my rear end the other day at 26k miles, and the magnetic plug had a 1/4" of some type of sludge/shavings, etc on it. i have never changed the oil yet, but i plan to on my next day off. i have never really been happy with the performance of my LSD, it seems that sometimes it works and sometimes it doesn't under the same type of conditions... could this sludge be premature wear and failure of the LSD???



anybody else have the same findings? i tow about 4 to 5 times a year, (generally less than 2k miles/yr).



jeremy

 

[LSMITH]

My LSD had over 40K miles on the factory oil fill and there was some very fine metal particles on the magnet. There was not anything more than just a coating on the magnet. The oil was also still light colored and smelled like a fresh fill. I tow very little, might have something to do with it. If you have particles any bigger than small specs, like the finest filings you would get with a file, there is something wrong.

 

[Vaughn MacKenzie]

I changed out my OEM fluid at only 2500 miles (LSD). It was looking pretty bad with quite a bit of metallic sludge on the plug magnet. I put in the Mobil synthetic 75W90 lube in and changed it again at 25,000 miles. It looked great. I put Amsoil in on that change and will go 30K this time.



Vaughn

 

[Dave Fritz]

I can tell you that 70,000 is way too long. I was putting off a rear diff oil change until I got the Mag-Hytec cover, and by the time I got around to dumping the oil it looked and smelled burned. My gears, bearings and Lockright all looked OK, but I will NOT go that long again.



OTOH - When I changed oil at 20,000 miles, the oil was still honey colored with some darkening from oxidation and smelled OK. Somewhere between 20k and 50k should be a reasonable interval with regular gear oil.



This time, instead of using Mopar dinosaur oil I used Torco 80W140 synthetic. Anyone have experience with this stuff? How long will it go compared to regular gear oil? It has an excellent reputation among the race teams here, but they don't run for thousands of miles between oil changes.



Dave

How my oil looked (left) and how it should look (right):