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Old 06-27-2013, 09:55 PM
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Join Date: Jun 2013
Location: Ohio
Age: 43
Posts: 3
Gender: Male
Vehicle: 2008 Dodge Ram 1500 Big Horn
Trim Level: Big Horn
Color: Silver
Engine: 2003-2008 345ci (5.7L) Hemi V8 345hp 375lb/ft
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Originally Posted by TNC View Post
OK, I think most are aware of the recommendation about 5W-20 motor oil and the possible relation to MDS operation...or are they? We're seeing a lot of transmission and driveability complaints from people that seem to be related to the MDS and probably not really transmission related. I'm curious if some of those complaints might be connected to running the wrong oil viscosity. Those of us who change our own oil know what went into the motor. I don't think that many people change their own oil anymore, so I'm wondering...are they sure they're getting the 5W-20 recommended viscosity? Is the MDS system, especially at the lifters, really that sensitive to the 5W-20 oil vs. another viscosity? Could some of these alleged shifting and driveability issues that seem to be connected to the MDS actually be related to the wrong oil viscosity? Would the wrong oil cause an imbalance or some other performance related symptom at the lifters to result in a very noticeable MDS operation glitch? Just thinking out loud here, as I was preparing to change my new truck's oil for the first time...with 5W-20 of course...LOL!

Forgot to add, I really haven't had any issue with the MDS kicking in and out. Yes, I can feel it, but it's not particularly annoying or causing any least from my perspective. People are different, however, and some can't stand even the slightest perceived disruption in the power delivery. Some might call them anal and some might call it preference, but you have to admit that some may be a bit hypersensitive to some quirks in any vehicle's operation.
I have an 08 Hemi Ram and I have been running 5W20 Royal Purple. That being said, I have seen bulk Mobile 5W30 used extensively in both car and truck Hemi MDS powertrains with few incidents over the last 5 years. With the TSB in hand, I initially questioned the wisdom of doing this, but it has been cost prohibitive.
As for my own truck, I am a technician first and realize the design intent behind the thinner viscosity oil. I need this truck to last to 200K and am willing to pay for top shelf lubricants.
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