The 6.4 HD Hemi Thread

[67Guzzler]

67Guzzler, at what speed is your highway driving? You get great mpg IMO.

I'm between 65 and 67. I can get MDS to stay engaged flatland without a headwind for much of the time @ 65.

Observations:

Along with headwinds, I noticed that TIRE PRESSURE is huge. At 45 lbs all the way around, I lose about 3/4 a MPG. If I'm at 80 all the way around, the rolling resistance is greatly reduced.

In my observations, speed, headwinds and tire pressures are the biggest factors (aside of terrain).

-Guzzler

 

[NewBlackDak]

I'm between 65 and 67. I can get MDS to stay engaged flatland without a headwind for much of the time @ 65.



Observations:



Along with headwinds, I noticed that TIRE PRESSURE is huge. At 45 lbs all the way around, I lose about 3/4 a MPG. If I'm at 80 all the way around, the rolling resistance is greatly reduced.



In my observations, speed, headwinds and tire pressures are the biggest factors (aside of terrain).



-Guzzler

Same here. I run at 65. It's low enough to take out some of the harshness, but high enough to not drop the mileage and to still tow anything I deal with normally.


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[LDBagger17]

My warranty is almost out, think I'm gonna put 4.56"s in my truck. Does anyone know if any reprogramming needs to be done for speedometer if so what

 

[U&A]

As for tire pressures, we cant forget that different PSI's have a huge affect on proper tire wear. Thats what i base my pressures on. 5lbs + or - can make a huge difference in tire wear throughout its life.

 

[GsRAM]

I run mine at 70 cold all the way around. 80 if I'm loaded to camp with the tt hooked up. Yeah, it rides harsher than the half ton i had and i expected it to. I actually like it that way. My 1500 Silverado felt more like a cadalliac than a truck.

 

[67Guzzler]

As for tire pressures, we cant forget that different PSI's have a huge affect on proper tire wear. Thats what i base my pressures on. 5lbs + or - can make a huge difference in tire wear throughout its life.

I run mine at 70 cold all the way around. 80 if I'm loaded to camp with the tt hooked up. Yeah, it rides harsher than the half ton i had and i expected it to. I actually like it that way. My 1500 Silverado felt more like a cadalliac than a truck.

The door jambs on my 2500 say 80 PSI rear and 60 PSI front.

-Guzzler

 

[pytbul]

My warranty is almost out, think I'm gonna put 4.56"s in my truck. Does anyone know if any reprogramming needs to be done for speedometer if so what

Nothing needs to be done. Gear change will not affect speedo.

 

[U&A]

The door jambs on my 2500 say 80 PSI rear and 60 PSI front.

-Guzzler

Those PSI's are ment for when your truck is fully loaded. Not necessary when daily driving without a trailer or heavy payload.

 

[U&A]

Nothing needs to be done. Gear change will not affect speedo.

If different sized tires affect your actual speed vs what your speedo says, than how will a gear change NOT affect your actual speed vs what the speedo reads?

 

[67Guzzler]

Those PSI's are ment for when your truck is fully loaded. Not necessary when daily driving without a trailer or heavy payload.

That is incorrect.

There's a well-known requirement on 2500 that force you to set the tires very close the pressures in the door jamb. Otherwise not the light on the dash will illuminate.

The dealer will do nothing to adjust the threshold for tire pressures. They used to, but FCA took that ability away from their programming equipment a few months back.

This is well-documented. You can read all about it here or if you Google RAM 2500 TPMS tire pressure requirements.

3500's Don't Force the tire pressures on you like 2500's. The TPMS system on 2500 trucks is totally different.

-Guzzler

 

[Andrew09HEMI]

My dealer was able to change my tire pressure settings so I can run a more comfortable setting. No I won't mention the dealer but they definitely can just need to find one that's got creative.

 

[drittal]

Or you could do what I did and just accepted the tire pressure warning light. Lowering the pressures makes a noticeable difference in ride and helps tire wear


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[pytbul]

If different sized tires affect your actual speed vs what your speedo says, than how will a gear change NOT affect your actual speed vs what the speedo reads?

Your sensor for speed is off the tone ring of the ring gear. So anything before that will not affect it. Changing tire sizes affect the revolutions per mile the axle shaft turns, therefore changing the speedo.

 

[RAM_Designs]

If different sized tires affect your actual speed vs what your speedo says, than how will a gear change NOT affect your actual speed vs what the speedo reads?

The speedo is determined by the revolutions of the rear axle. If gears made any difference, then your speedo would change every time the truck shifted gears as well. The reason why tire size matters is because it slows down the rpm's of the rear axle. For instance, I still haven't recalibrated my speedo, and I'm actually going 10% faster than what the speedo says. The plus side of this is that my EVIC is 100% dead on most of the time, because I'm actually traveling further than what the EVIC thinks I am.

 

[67Guzzler]

My dealer was able to change my tire pressure settings so I can run a more comfortable setting. No I won't mention the dealer but they definitely can just need to find one that's got creative.

Not if they update their equipment. The latest WiTech equipment doesn't allow them to. And once they get the update, they can't flash back to the prior version.

No amount of creativity can work around that.

-Guzzler

 

[RAM_Designs]

Or you could do what I did and just accepted the tire pressure warning light. Lowering the pressures makes a noticeable difference in ride and helps tire wear


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This, I just ignore the light. I run 65psi max tires right now anyways, keep them 60 in the front and 50 in the rear. I tell NTB this every time the rotate my tires, but the rears will always be aired up to 80 and I'll have to let air out for 10 minutes when I get home.

 

[Cardr]

2016 hemi clatter and transmission surge

My 2016 developed the knock back in February 2017. Starting making noise at 10,500 miles. Plus the transmission surges in 3rd and 4th gear. Can barely haul 1,000 lbs safely. Afraid to even tow a trailer now because of how much it slips and surges. I've had 2 hemi rams before this and they were whisper quiet (2011 and 2013). My 89 f250 351 with 289,000 miles and with a leaking exhaust is quieter than this hemi.
Dealer is not acknowledging the problem.
Engine has been getting louder since the problem developed. It can also be heard at 1,500 rpm 2,100 rpm and 3,000 rpm when hot. Also coming down on revs from 2,000 rpm to 1,400 rpm when hot. It sounds as loud as a diesel now and the dealer is denying that they can even hear it. This is clearly a rod knock. It was not noticable the first 10k miles when new. This was my Dream Truck that is quickly turning into a nightmare. We'll see what my case manager says tomorrow.

https://youtu.be/yKs4fblL4MI
https://youtu.be/lEOfJnuKTX4
https://youtu.be/c-fyrS1OUNI

 

[CanadianRAm16]

Looked at your video. Sounds like the knocking is an issue with a lifter. Does this only happen on cold starts and last for 20-30 seconds?

 

[Cardr]

It is there when warm also. It gets quieter when idling 40 seconds but you can still hear it. Then when warm if you hold revs at 1500 or 2100 rpm you can hear it as well. Coming down from revs the knock is heard at 1500 rpm.

 

[Andrew09HEMI]

It is there when warm also. It gets quieter when idling 40 seconds but you can still hear it. Then when warm if you hold revs at 1500 or 2100 rpm you can hear it as well. Coming down from revs the knock is heard at 1500 rpm.

Find a new dealer! Clearly something isn't right and that dealer doesn't want to help.