mike hes saying gcwr is 14k, which is including the weight of the trailer, hes not saying 14k is what the truck can tow.

 

Yup, this is out of the 08 owners manual.

Engine Oil Viscosity (SAE Grade)
SAE 5W-20 engine oil is recommended for all operating temperatures. This engine oil improves low temperature starting and vehicle fuel economy. The engine oil filler cap also shows the recommended engine oil viscosity for your engine. For information on engine oil filler cap location, refer to the “Engine Compartment� illustration in this section.

NOTE: Vehicles equipped with a 5.7L engine must use SAE 5W-20 oil. Failure to do so may result in improper operation of the Multiple Displacement System (MDS). Refer to “Multi Displacement System� under “Starting and Operating� for more details.

NOTE: For 2500/3500 trucks with a 5.7L engine operating under a gross combined weight rating of 14,000 lbs. or greater, SAE 5W-30 engine oil is recommended for all operating temperatures

 

Has anyone heard a rumor of MDS in the 4.7? It's an OHC engine, right? That would seem to make that a bit easier.

 

Thanks for all the feedback, guys. I'm going to go ahead with the 0W-20 synthetic & see how things go.

Another thing popped up while I was searching through past threads on Mobil 1 and other synthetics... Is it true that the new Rams come from the factory with Synthetic lube in the diffs & the transfer case? I saw someone post that, but didn't see anything confirming it or denying it. Anyone know?

 

I believe they do. The manual on my '03 specifies synthetic for the diff, but just ATF+4 for the tranny and power steering. When I changed my tranny fluid a few months ago, I used Valvoline ATF+4. I could swear it's synthetic, but considering I paid <$3 a quart, it probably wasn't.

 

Well, Looks like I'll be putting off teh change to the 0W-20 Mobil one for another 3000 miles. I forgot that the dealer does the first LOF for free... and who am I to argue with a price like that?

I'll still be doing the change, just a few more miles down the road.

While I was there, I asked about what fluids come from the factory in the '08 Rams. I was told that the rear diff comes from the factory with full synthetic in it, but that the front diff & the transfer case still come with dead dinosaurs in them. He wasn't sure what weight lube synthetic was used from the factory, but for petroleum-based lubes, all his dealership uses is 80w90 gear lube.

Unless I can find out what weight lube is used in the rear, I'll probably have it changed out as well. One of the local shops here does a complete 4x4 synthetic exchange for $100. Doesn't sound bad to me, so I'll probably go with that rather than do it myself. Never mind the fact that the smell of used gear oil makes me want to launch lunch...

 

Look at the oil cap under the hood. On my 2007 4.7 Ram it says 5W20. That's what I use. I made the synthetic switch at my 4th oil change at 8k miles, now I'll let it run to 3k intervals.

 

The rings should have seated by the first oil change. After a full motor rebuild inmy old Bimmer, I ran dino at first with oil changes at 100 mi, 500 mi, and then finally switched to full synthetic at 1500 mi. So you should be fine to switch to synthetic any time.