Advice?

[Jesusplusnothing]

I had exactly what you describe in my 2016. Ram had just provided a new tranny under warranty, and occasionally upon downshift, it banged so hard at times, I expected to see the rear end dropped in the road behind me.

The dealer installed updated tranny software and the problem dissappeared.

Mine never does the bump on shifting. Only when pressing the accelerator.

 

[Marshall]

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.

I don't usually feel it, but if the window is down I can hear it, mine will cut in and out diddling around town at 30mph, 40-50km, when its cold as in last few days -35 to -40 I use the buttons, helps to warm the truck I think well.
BTW when its -40, I sit in the house and watch the people out walking the dogs.

 

[Wild one]

To be f

To be fair my wife never felt it. Several coworks never felt it.

And you expect us not to give you a hard time on that comment

 

[Jesusplusnothing]

And you expect us not to give you a hard time on that comment

I know lol I regretted it after I said it.

 

[Marshall]

it was a real temptation

 

[Sherman Bird]

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

They can't turn anything off related to CAFE or emissions control systems. Their hands are tied.

 

[Dusty]

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.

I

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.

It would be good to know which axle ratio you have.

I did not read all of the posts in this thread, so this may be an echo.

I've had two 8 speed 5.7s and have never been able to detect ("thud") when the MDS kicks in at any speed and no one I know that has an 8 speed with MDS seems to have a similar condition. But with only 1700 miles on your vehicle it may be a little premature to figure there is a mechanical issue. Things are still breaking in and you may not have had enough driving time to establish a good learn algorithm in the TCM.

However, I think it is probably a good idea to put the issue on record even if they say everything is normal. (NOTE: The "thud" issue on my '14 turned out to be binding in the driveshafts.)

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 104733 miles.

 

[Jesusplusnothing]

I

It would be good to know which axle ratio you have.

I did not read all of the posts in this thread, so this may be an echo.

I've had two 8 speed 5.7s and have never been able to detect ("thud") when the MDS kicks in at any speed and no one I know that has an 8 speed with MDS seems to have a similar condition. But with only 1700 miles on your vehicle it may be a little premature to figure there is a mechanical issue. Things are still breaking in and you may not have had enough driving time to establish a good learn algorithm in the TCM.

However, I think it is probably a good idea to put the issue on record even if they say everything is normal. (NOTE: The "thud" issue on my '14 turned out to be binding in the driveshafts.)

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 104733 miles.

Thank you for the reply. I have the 3.21 gear. In the beginning it started as a lurch forward like being mildly rear ended. That went away with mileage. I'd say around the 1200 mark. The bump started I'd say around 800ish. It also isn't when mds kicks on. It's when mds turn off. As in the 4 deactivated cylinders are reactivated.

Honestly thud I think was the wrong word. It seems to be a much more aggressive word then what actually happens. Bump I believe is a better word.

A bump seems to be the most common thing people are experiencing. It's also so incredibly faint most the time, that most folks don't even feel it. Just a couple times it's been a pretty big bump.

One time specifically was going down hill at about 35 mph when I pressed the accelerator it felt like I had hit a speed bump.

For sure though it does not do it period using the gear selector on the steering wheel to turn off mds.

I have a tendency to over think things to. So I feel every little thing while driving.

I think you're correct though. Things are breaking in and what not. I have an appointment for wed with the dealer. So I'll get everything on record then. I guess the good thing is I got a life time powertrain through the dealer.

 

[ramffml]

I've had two 8 speed 5.7s and have never been able to detect ("thud") when the MDS kicks in at any speed and no one I know that has an 8 speed with MDS seems to have a similar condition.

It's a very common complaint, it's all over this forum and the others as well. The transition is not always seemless. Mine did it excessively when it was new, both when going in and out of MDS. Now after 95,000+ kms it only does it when exiting sometimes, but I've kept MDS disabled for about 93,000 kms as well.

 

[Dusty]

Thank you for the reply. I have the 3.21 gear. In the beginning it started as a lurch forward like being mildly rear ended. That went away with mileage. I'd say around the 1200 mark. The bump started I'd say around 800ish. It also isn't when mds kicks on. It's when mds turn off. As in the 4 deactivated cylinders are reactivated.

Honestly thud I think was the wrong word. It seems to be a much more aggressive word then what actually happens. Bump I believe is a better word.

A bump seems to be the most common thing people are experiencing. It's also so incredibly faint most the time, that most folks don't even feel it. Just a couple times it's been a pretty big bump.

One time specifically was going down hill at about 35 mph when I pressed the accelerator it felt like I had hit a speed bump.

For sure though it does not do it period using the gear selector on the steering wheel to turn off mds.

I have a tendency to over think things to. So I feel every little thing while driving.

I think you're correct though. Things are breaking in and what not. I have an appointment for wed with the dealer. So I'll get everything on record then. I guess the good thing is I got a life time powertrain through the dealer.

"One time specifically was going down hill at about 35 mph when I pressed the accelerator it felt like I had hit a speed bump."

Okay, you will notice that when you are de-accelerating from speed and the accelerator peddle is not touched for a period, the transmission will downshift through the gears until it matches the gear to the road speed.

The primary reason is to reduce emissions. After a predetermined time set in the PCM (around 1 second) and in that condition, the PCM shuts off fuel to all injectors until the PCM senses input from the accelerator (depressed again.)

I can't say I've experienced anything in the same scenario, but I probably don't ever experience that same scenario. However, that's a condition I would definitely inform the service advisor and tech. about.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 104733 miles.

 

[Tulecreeper]

It's a very common complaint, it's all over this forum and the others as well. The transition is not always seemless. Mine did it excessively when it was new, both when going in and out of MDS. Now after 95,000+ kms it only does it when exiting sometimes, but I've kept MDS disabled for about 93,000 kms as well.

I run with my ERS engaged almost all the time to lock out the MDS. Occasionally I will drive for a bit without doing it, just to "keep it working", so to speak. When the MDS does kick in, I can feel/hear a growl from behind the firewall, and there is a weird feeling in the accelerator pedal. That bugs me, so I usually run in ERS mode.

 

[Marshall]

I live on a hill, going down when leaving, a few times I have felt a thump, when shifting , one reason is these trucks have a hill hold on them and I think that adds to the thump, it is not very often, going up the hill ,I don't think I have ever noticed anything. all this would be at slow speeds around town, 20-30mph, 40-50km/h sometimes in Dr , sometimes MDS locked out.