Advice?

[Jesusplusnothing]

So just bought a new 1500. At this point it only has 1700 miles. When I'm driving along doesn't matter what speed or gear. It is also super random. When I press the accelerator sometimes you can feel a thud from under the truck.

It does not effect rpms, it does not slow the truck down. It also only happens when mds is turned in. If I ddo the - 8+ on the steering wheel I've yet to have it happen. Turn mds on it'll take a while but it'll do it.

Sometimes it's a really hard thud. Sometimes it's a soft thud. Dealer has already down a software update to the transmission.

Mostly wondering if anyone has heard of this happening before. I'm not exactly happy about having to take a brand new truck in for diagnostics. Especially when that's gonna take 2-3 days.

 

[Drummin4jc]

I know you’re not thrilled about taking it to the dealer but that sounds to be your best bet. Get them to fix it under warranty before it causes any more issues that will haunt you down the road (after warranty)

Adam

 

[Jesusplusnothing]

I know you’re not thrilled about taking it to the dealer but that sounds to be your best bet. Get them to fix it under warranty before it causes any more issues that will haunt you down the road (after warranty)

Adam

I know and I'm gonna. Just more wondering what I could tell the dealer to start looking at. From reading a thread about it from 2019cthere is no "fix" just it may go away it may not. Seems to be a software thing in the transmission. No dealer around my city has ever heard of it before though so idk.

 

[WoodGuy]

When the MDS kicks in/out at lower speeds on mine, I'm very aware that its doing it. So much so that I automaticly turn it off as soon as I start driving. I wouldnt call the sound mine makes a thud, but I dont like it. I'm not saying dont take it in so the dealer can look at it, just dont be surprised if they say they cant detect anything abnormal.

 

[Jesusplusnothing]

When the MDS kicks in/out at lower speeds on mine, I'm very aware that its doing it. So much so that I automaticly turn it off as soon as I start driving. I wouldnt call the sound mine makes a thud, but I dont like it. I'm not saying dont take it in so the dealer can look at it, just dont be surprised if they say they cant detect anything abnormal.

I say thud cause idk how else to describe it. I guess bumb would be a better term. It almost feels like the torque converter unlocking. Still only ever happens when mds is enabled.

To me that means something to do with the mds communicating with the tcm. Maybe telling the torque converter to stay locked longer then it should or for it to stay in a higher gear then it should be.

 

[DanAR]

I figured the MDS only kicked in at some programmedd higher speeds - say 50 mph or so. Is that incorrect? I only have about 1500 miles on my truck, mostly around town. But I can’t remember feeling anything so far that I would associate with MDS activating/deactivating.

 

[Jesusplusnothing]

Mine definitely kicks on at any speed just depends on if I press the accelerator or not. Seems to be set up to where if you're coasting it kicks on. Just my experience.

 

[Tulecreeper]

I purposely engage my ERS (-8+) as soon as I put it in gear - which disables the MDS - and I have had zero issues. I can't imagine when I would ever want my truck to run on 4 cylinders. Besides, when the MDS kicks in I hear this "growling" sound from behind the firewall and there is a change in my throttle pedal and that bugs me.

 

[Sherman Bird]

I know and I'm gonna. Just more wondering what I could tell the dealer to start looking at. From reading a thread about it from 2019cthere is no "fix" just it may go away it may not. Seems to be a software thing in the transmission. No dealer around my city has ever heard of it before though so idk.

You are experiencing harshness in the transition from either 4 to 8 cylinder or vice versa or both. This problem exists on all 6 or 8 speed transmissions in Ford, GM, and Ram. The "fix" is ludicrous, IMHO and in my professional view as a transmission specialist. That "fix" is to apply the torque converter clutch at high slip to "cushion the event", to alleviate the thud. That is a point of accelerated wear and heat.
The reason you don't experience it in manual shift mode is that it is not part of the algorithm outside of complete automatic mode.

 

[Jesusplusnothing]

Thank you for that information. Maybe I can use that to argue my dealer into turning the mds off lol.

 

[Jesusplusnothing]

You are experiencing harshness in the transition from either 4 to 8 cylinder or vice versa or both. This problem exists on all 6 or 8 speed transmissions in Ford, GM, and Ram. The "fix" is ludicrous, IMHO and in my professional view as a transmission specialist. That "fix" is to apply the torque converter clutch at high slip to "cushion the event", to alleviate the thud. That is a point of accelerated wear and heat.
The reason you don't experience it in manual shift mode is that it is not part of the algorithm outside of complete automatic mode.

Thank you for that information. Maybe I can use that to argue them into turning the mds off.

 

[Tulecreeper]

You are experiencing harshness in the transition from either 4 to 8 cylinder or vice versa or both. This problem exists on all 6 or 8 speed transmissions in Ford, GM, and Ram. The "fix" is ludicrous, IMHO and in my professional view as a transmission specialist. That "fix" is to apply the torque converter clutch at high slip to "cushion the event", to alleviate the thud. That is a point of accelerated wear and heat.
The reason you don't experience it in manual shift mode is that it is not part of the algorithm outside of complete automatic mode.

Well, I'm glad we cleared that up. Tomorrow's lesson -

 

[Tulecreeper]

Thank you for that information. Maybe I can use that to argue them into turning the mds off.

I don't think there is a way to do that, other than you manually engaging your ERS (-8+).

 

[Jesusplusnothing]

They

I don't think there is a way to do that, other than you manually engaging your ERS (-8+).

They can fca just "won't let them". When I go in Monday to have it looked at. Though seems like a waste of time and miles now. The tech is gonna ride with so I can show them the problem. I thought about offering him 500$ to shut it off.

 

[CanuckRam1313]

Like many have said, this points to the awful MDS system inherent in our vehicles that affects our 8spd transmissions. Some feel it more than others, but it's a defined aggravation IMHO.

I also feel that it can't help ones transmission kicking in and out, shuddering and feeling like it's stumbling as it's trying to engage the transmission to get into the right gear for the applied load and speed.

These transmission feelings are also more pronounced at low speeds like in-town driving and traffic.

In 4.5 years of ownership I never use the MDS, and it's marginal at best that it saves any fuel whatsoever. So little that I don't care to utilize this useless technology as my driving enjoyment far outweighs any perceived benefits that MDS is purported to provide.

Put it in 8 and enjoy your new Ram ownership experience

 

[CanuckRam1313]

They

They can fca just "won't let them". When I go in Monday to have it looked at. Though seems like a waste of time and miles now. The tech is gonna ride with so I can show them the problem. I thought about offering him 500$ to shut it off.

Offer nothing, and don't request it turned off on your new vehicle, especially at the dealership level. You don't want that liability and/or possible stain on your warranty in their system! That's my opinion only, though.

Let the tech do their thing, get your report, and then just manually put it in 8 and carry on.

If you really want to save your transmission, install the transmission cooler bypass valve that so many of us on this forum are using and see your trans temps drop like 30c.

That, and do regular transmission fluid/filter services, too!
This is predictive and preventative maintenance to ensure that your trans stays happy and healthy for many miles and years.

 

[Jesusplusnothing]

Offer nothing, and don't request it turned off on your new vehicle, especially at the dealership level. You don't want that liability and/or possible stain on your warranty in their system! That's my opinion only, though.

Let the tech do their thing, get your report, and then just manually put it in 8 and carry on.

If you really want to save your transmission, install the transmission cooler bypass valve that so many of us on this forum are using and see your trans temps drop like 30c.

That, and do regular transmission fluid/filter services, too!
This is predictive and preventative maintenance to ensure that your trans stays happy and healthy for many miles and years.

You have my attention lol. You wouldn't be able to share a link to that bypass would you? I suppose I will take your advice. The powertrain does have a lifetime warranty so I guess I just shouldn't worry about it.

 

[Tulecreeper]

They

They can fca just "won't let them". When I go in Monday to have it looked at. Though seems like a waste of time and miles now. The tech is gonna ride with so I can show them the problem. I thought about offering him 500$ to shut it off.

I meant "legally" turn it off. See this:

MDS - fix it or turn it off

Recently my truck started to make what has been described as a ratcheting sound off throttle ECO light on, goes away in neutral and if selecting a gear or giving more throttle... did lots of research and based on when it happens and how I can get it to go away it is the MDS. I have 150,000...

www.ramforum.com

 

[CanuckRam1313]

You have my attention lol. You wouldn't be able to share a link to that bypass would you? I suppose I will take your advice. The powertrain does have a lifetime warranty so I guess I just shouldn't worry about it.

Our 8spd transmissions are known to run hot regardless, and if you're towing and/or hauling heavy, they can get even hotter. As I'm sure you know, heat kills transmissions

Plus, the existing thermostat valve in the transmission cooler is a known issue and if it seizes you'll cook your transmission.

@caulk04 is a highly respected member of this community, and his designed trans cooler bypass valve is fantastic. I have one, my stepdaughter has one, my buddy has one, too. We all immediately got the benefits of the reduced trans temps.

Many on in this community utilize his product and have nothing but great things to say about its benefits.

Reach out to him and he will get you sorted

 

[Jesusplusnothing]

I meant "legally" turn it off. See this:

MDS - fix it or turn it off

Recently my truck started to make what has been described as a ratcheting sound off throttle ECO light on, goes away in neutral and if selecting a gear or giving more throttle... did lots of research and based on when it happens and how I can get it to go away it is the MDS. I have 150,000...

www.ramforum.com

Yes lol this I knew that's why i was thinkin if I had in alone 500$ might sound real nice. You're right though I should just drop it. Wait for Diablo to make a tuner for that year turn it off and take the tuner off when I need to service it. Thank you for the help!