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MDS & Oil Viscosity

26K views 22 replies 16 participants last post by  mattfranks23 
#1 · (Edited)
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 grief...at 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.
 
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#3 ·
Not sure how MDS affects transmission operation.

Typically its cold oil viscosity thats critical to engine controls like variable valve timing and mutiple cylinder control, etc... These types of controls are managed with oil pressure and in order to have adequate pressure at colder operating temps the oil has to be thin enough to flow. Once the oil reaches operating temp, it usually thins out enough that flow isn't an issue. Thats why many manufacturers require a cold viscosity of 0 or 5. I think the hot viscosity of 20 is to hel achieve mileage figures.

I personally don't like the driveability when MDS is active, but I like the ability to defeat it. Still haven't decided if it actually saves me any fuel.
 
#4 ·
Not sure how MDS affects transmission operation.

Typically its cold oil viscosity thats critical to engine controls like variable valve timing and mutiple cylinder control, etc... These types of controls are managed with oil pressure and in order to have adequate pressure at colder operating temps the oil has to be thin enough to flow. Once the oil reaches operating temp, it usually thins out enough that flow isn't an issue. Thats why many manufacturers require a cold viscosity of 0 or 5. I think the hot viscosity of 20 is to hel achieve mileage figures.

I personally don't like the driveability when MDS is active, but I like the ability to defeat it. Still haven't decided if it actually saves me any fuel.
No, I don't think MDS has any direct effect on the transmission or shifting. I just think many are attributing "some" driveability issues to the tranny when in fact it's probably the MDS...especially in town. I believe the often mentioned "shudder" or rough shifting is sometimes the MDS kicking in and out and especially more noticeable in slower city driving. MDS can feel a bit like the tranny shifting in and out of a couple of gears at slower speeds IMO. A quick check of your tach will usually show that's not the case. And I'm not talking about torque converter issues and such that are more common in the case of some/many of the 2011 models. While I have no complaints about the shifting and operation of the MDS on my '12 Express, I think some are hypersensitive to the operation of MDS and the shifting characteristics of a truck. I think many who expect luxury car smoothness out of a tranny made to tow thousands of pounds might be somewhat disappointed with most truck trannies. Shifting pressures and stronger components necessary to take towing abuse almost always have a lack of silky smoothness "compared" to a sedan tranny. In fact those of us who have owned numerous trucks over many years have seen the result of manufacturers trying to deliver car-like smoothness and efficiency in their truck trannies. Towing often suffered and failures increased.
 
#6 ·
one time my Remote Start would not work
so i used the remote to unlock the doors & used the key to start it
when i did the SEE DEALER light came on
I was surprised because i had just had it in a couple days before for servicing

The Service Writer was also surprised to see me
They did a code check & it came through as a Drive ability issue, due to incorrect oil viscosity, turns out that a tech had used 10W-30, instead of 5W-20
 
#8 ·
One time I was driving down the road and all of a sudden I see a light off to my right side. It said "You drive like a jacka$$, You're an idiot". I was shocked until I realized it was my wife with a flashlight behind a piece of paper. No dealer service was needed that day.
 
#10 ·
Great points made on this subject. The old saying goes, "When you want somethin done right, you gotta do it yourself". It's not being anal; it's called being thorough......Torquing engine oil drain plug to 23-25ftlbs; 3/4 to full turn on oil filter just after contact; filling with THE PROPER VISCOSITY OIL and not overfilling. Mistakes happen like in the instance of that dealerships service department mess up with using 10W30. Then the owners impression of the incompetence and loss of trust in their dealer, and more so, in the brand itself lingers indefinitely.
 
#14 ·
Been using M1 5-30 since changing out the factory fill at 6K miles.
Now at 19K miles (1 year). No check engine lights. No noticeable difference in how MDS operates, no noticeable difference in cold engine noise (don't think my truck is particularly noisy anyways).
I suspect my hot viscosity is close enough to 5-20 hot viscosity that there's not an issue.
Not making any recomendations... just answering the question!
YMMV
 
#12 ·
only the Ram 1500 has MDS & use the 5w20
the 2500 & 3500s don't have the MDS & those engines use 10w30
both are the exact same short block

you really have to understand the MDS system & how it closes off the 4 unused cylinders to really understand why the lighter weight oil is used for the MDS
it is way to technical for me
 
#15 ·
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.
 
#16 ·
I am running 5w30 royal purple, only for a little over 200 miles though (first oil change in my truck), no issues, lights or anything negative, just a better running truck.
 
#17 ·
And with most here that shut the MDS off either by Tuner or by way of the ERS, the use of 10W30 could definitely work. I haven't used my MDS for a year now and will consider the 10W30 switch more seriously.
 
#18 ·
I mix at least 3qts 5W30 and have use 4qts 5W30 in the summer with no problems. I just don't like straight 5W20, sorry that's me.
 
#20 · (Edited)
My owners manual clearly states if you can't find or have no access too 5W-20-->You can use 5W-30.

I myself have been a member of bobistheoilguy.com since 05 and in the time period until now. I know M1 AFE & EP 0W-20 and M1 0W-40 are some of M1 most Robust oils.

I have used M1 oils since I was 16-->I am now 49 and still use M1 in my new Ram. My first Oil Change I poured in 5Qts of M1 AFE 0W-20 & 2Qts M1 0W-40. After 500 miles I have had no issues. The 5.7L Idles and Runs Very Smooth!!!

Mind U-->I will not tell any other 2014 Ram 5.7L owner to do this. This is just my own personal experience!
 
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