Picking up a new to me 2007 Chevy 3500 EXT CAB LB 4x4 LMM . It has 22,000 miles on it , I will use it to tow my fifth wheel. My only problem is i wanted to do some matainance on the truck before I tow with it but the dealer seems to have lost the owners manuals. My first question is how many manuals show I be getting is there one for the LMM or is it all in one ? My other questions are about oil and transmission, I think the 2007 the allison is useing DEX VI is that corerect ? my 03 8.1 allison used dex II. does the six speed take the same 7-8 quarts as the 5 speed with a drain and filter?? And last how many quarts does the engine take for a oil change with filter and what is the factory recomened grade for the oil? I really appresate the help, I a bit upset when the dealer said he did not know where the owners manuals were even more so being new the duramax.

There are two manuals, the Silverado 2500hd manual and then a smaller duramax manual. Tranny fluid is DEX VI. Takes 10 quarts of engine oil, 15w40.

You should get one big one that is more for the general truck and a supplemental one that is specific to the duramax. As far as the fluids and qty's. go, you seem to be on the right track. On the Amsoil website they have a section where you can look that up (What kind of fluid and how much goes where).

Your Duramax will take 10 qts (2.5 gal) of oil in the engine with the filter change. With dual bypass it will take 11.5 qts. Recommended oil for pre DPF trucks is 15W-40. The Newer 2007.5 and up trucks that have a DPF need the CJ-4 rated oil which is 5W-40

The Allison transmission will take 7.4 qts (2 gal) for a pan drain with the spin on filter change. Get 5 gal if you are doing a flush to get the oil into the torque converter. For the Allison you need the Torque Drive ATF if you are going to use the Amsoil.

The rear diff will take 4 qts of 75W-90 gear oil with the stock cover. If it’s an aftermarket such as the Mag-Hytec it will take 7.5 qts. If you are doing a lot of towing or hauling heavy loads I recommend you use 75W-110 in the rear diff.
The Amsoil Product for this is Severe Gear oil.

If you have 4wd:

The Front diff will take 2 qts 75W-90

The transfer case will take 2 qts of either ATF or 5W-30 synthetic motor oil depending on which way you want to go. If you use the over fill method through the speed sensor it will take 3 qts.

There is nothing really special except with the Trans spin on filter. There is a magnet on the top of the filter that will need to be cleaned real well and put back on top of the new filter before installing it. Also there is a magnetic drain plug in the front diff that needs to be cleaned it will have shavings on it.

On the fuel filter make sure you don’t cross thread the plastic WIF sensor. It’s easiest to take out the inner fender well on the pass side to get at the fuel filter its 8 plastic clips.

Let me know if I may help with your filters & fluids at wholesale pricing with the DP offer.


Dane

The Allison transmission will take 7.4 qts (2 gal) for a pan drain with the spin on filter change. Get 5 gal if you are doing a flush to get the oil into the torque converter. For the Allison you need the Torque Drive ATF if you are going to use the Amsoil.
I'm pretty ignorant with regards to automatic transmissions, so here's a stupid question. Doesn't the oil in the torque converter circulate with the oil in the pan? I'm confused why you would only change 2 gallons...

sorry if I sound picky but I though the front took 80W-90. Guess it don't make a great difference but I know the 80W-90 is tougher to find an most places.

the reason why he is doing only 2 gallons is because he is just dropping the pan fluid. If you do a complete flush like the guy above said including the torque converter then 5 is the right number. Think the case is 4 gallons and the torque converter 1 gallon.