V4 to V8 Rumbling - Cause For Concern?

[OffTheAir]

Hi all, hope you're doing well!

I'd like to apologize ahead of time if this topic has been covered over and over again. I spent a lot of time digging in the forum and was able to find some topics pertaining to the issue I'm currently having, but no definite answer.

To make a long story short, I've been starting to notice a new noise while driving the truck and it is directly related to the V4/V8 transition. When I am on the expressway doing about 70-80mph on light throttle, I get a deep rumbling noise that is almost exactly comparable to that of driving over rumble strips. When I release my foot from the accelerator it immediately goes away, same for when the truck finally jumps into V8 mode. The noise sounds like it's coming from the front of the truck but I really am not sure, it's not terribly loud. What I can only assume is that because it's in V4 mode the truck just struggles a little bit to get up to speed, and the delay from the factory tune on these trucks just makes it take a little while to finally jump to V8. It barely does it at any speed below 70-80.

Maybe I've just become a little bit more observant and it's been doing this forever, or maybe this is a sign of things to come (hopefully not). Really, I'm just looking to see if anyone has experienced issues like these and if it's considered normal. That's all I really care about. The noise and typical highway vibrations don't bother me at all, I'm not looking to disable AFM like a lot of people suggested in the threads I looked at, I just want to know if this is hurting the truck or this is standard procedure. If this is normal, shoot, I'll live with it!

If it helps at all, I just changed my spark plugs, performed a full tune up, and recently had a big repair at the dealership (radiator/water pump) where they told me there were no issues with the truck. My 6-Speed still shifts like it always has so I'd be very shocked if it had anything to do with that, and my engine seems to run just fine.

Thanks so much for reading this guys, I'm really looking forward to your feedback.

Edited January 21, 2021 by OffTheAir

[JimCost2014]

Miles on truck?

 

My guess is torque converter. 

 

 

[Grumpy Bear]

34 minutes ago, JimCost2014 said:

Miles on truck?

^^^^^^^^^^

[flyingfool]

  what i experienced is the rumble might not be the DoD but your lock up converter lugging the engine at too low an rpm. I think i need the adjust the parameters for lock up and un locked vs rpm on my truck

Edited January 21, 2021 by flyingfool

[OffTheAir]

10 hours ago, JimCost2014 said:

Miles on truck?

 

My guess is torque converter. 

 

 

10 hours ago, Grumpy Bear said:

^^^^^^^^^^

Hey guys! Thanks so much for the response. I just passed 97,000 miles on the truck.

 

Yeah, I figured  Kind of hoping it isn’t that.

[flyingfool]

find a local tuner that can just disable the lock up converter for 1-4th gear, this will solve lots of issues

[OffTheAir]

20 minutes ago, flyingfool said:

i adjusted my V4 mode to activate at 45 mph, this helps reduce wear on the dod sytem.  what i experienced is the rumble might not be the DoD but your lock up converter lugging the engine at too low an rpm. I think i need the adjust the parameters for lock up and un locked vs rpm on my truck

That’s very interesting. Out of curiosity, how’s you go about doing that?

 

Edit: Nvm, answered before my reply haha

Edited January 21, 2021 by OffTheAir

[flyingfool]

 purchase MPVI from HPtuners, buy credits and reprogramm it yourself.

Edited January 21, 2021 by flyingfool