5.7 Weird Lag when Accelerating??

[VictorLin0725]

Just test drove a Longhorn with a 5.7 Hemi today (no e-torque) and had some issues. The driving was smooth and problem free but when there were some straightaways, I gave it a lot of gas (almost floored it) and there were lag points at wierd times...Not just in the beggining but when I hit 20km/hr it jerked forward and when it hit around 40 it jerked again and again at 60...I'm I just not used to truck transmissions or is there an issue? I've read some stuff on the forums and It may be the cylinder deactivation? Compared the the 5.0 coyote its just not as smooth, it finally caught on at 60km/hr and started hauling and accelerated with even power. If it is the cylinder deactivation, is there any way to disengage it?

Thanks in advance

 

[troutspinner]

What was the temp where you test drove it? But no, this does not sound normal except maybe a cold start on a very cold day like today in Pa.

 

[SpeedyV]

Just test drove a Longhorn with a 5.7 Hemi today (no e-torque) and had some issues. The driving was smooth and problem free but when there were some straightaways, I gave it a lot of gas (almost floored it) and there were lag points at wierd times...Not just in the beggining but when I hit 20km/hr it jerked forward and when it hit around 40 it jerked again and again at 60...I'm I just not used to truck transmissions or is there an issue? I've read some stuff on the forums and It may be the cylinder deactivation? Compared the the 5.0 coyote its just not as smooth, it finally caught on at 60km/hr and started hauling and accelerated with even power. If it is the cylinder deactivation, is there any way to disengage it?

Thanks in advance

I agree with @troutspinner...this isn't normal at all. It's possible that the transmission needs to go through a re-learn, as there are many shift maps available and it can take time to smooth everything out.

 

[Gman]

Doesn't sound right at all. The 8 speed transmission is very smooth with shifts and the Hemi accelerates quickly and effortlessly.

 

[GATORB8]

That isn’t cylinder deactivation. Sounds like transmission shifts. The shifts in my truck are firmer than my 12 year old F150 I traded in. Easy to confirm, bet the tach dropped each time.

 

[VictorLin0725]

What was the temp where you test drove it? But no, this does not sound normal except maybe a cold start on a very cold day like today in Pa.

I agree with @troutspinner...this isn't normal at all. It's possible that the transmission needs to go through a re-learn, as there are many shift maps available and it can take time to smooth everything out.

Doesn't sound right at all. The 8 speed transmission is very smooth with shifts and the Hemi accelerates quickly and effortlessly.

Alright thanks. Just worried that it was a common issue. I'm pretty confident in ordering one now. Any of you tried an acceleration fron 0-60, and if so how smooth was the acceleration?

 

[SpeedyV]

Alright thanks. Just worried that it was a common issue. I'm pretty confident in ordering one now. Any of you tried an acceleration fron 0-60, and if so how smooth was the acceleration?

Well, I’m coming from an old GMC with a tuned 6.0 and 4.10 gears, so the HEMI doesn’t blow me away off the line. But it sure does love to sing at higher RPMs, and the transmission seems very well matched to its powerband. Shifts are well-timed and smooth.

 

[VaderRebel]

Any of you tried an acceleration fron 0-60, and if so how smooth was the acceleration?

Yeah, everytime a light turns green my foot thinks it has to dent the firewall. It's extremely good at getting the shift points just right. I like that a lot of owners use the word "effortless" to describe the hemi's acceleration.

 

[ExcursionDiesel]

On a new truck, the Transmission Control Unit hasn't gone through it's learning process so shifting improves with driving. At wide open throttle the truck shifts are firm and quick. You will feel a surge. All automatics with a firm shift do this. It's normal Under light throttle the transmission shifts are much softer. As mentioned. the transmission has profiles for different driving conditions.

The MDS (cylinder deactivation) is never active under acceleration...only under very light throttle conditions.

 

[User_3336]

MDS (cylinder deactivation) would definitely NOT be on during acceleration.

 

[Gman]

I don't feel those 'firm shifts' with the eTorque. It just goes. It's not a rocket, but it's also not a slug.

...and it sounds great doing it.

 

[MJP]

Just test drove a Longhorn with a 5.7 Hemi today (no e-torque) and had some issues. The driving was smooth and problem free but when there were some straightaways, I gave it a lot of gas (almost floored it) and there were lag points at wierd times...Not just in the beggining but when I hit 20km/hr it jerked forward and when it hit around 40 it jerked again and again at 60...I'm I just not used to truck transmissions or is there an issue? I've read some stuff on the forums and It may be the cylinder deactivation? Compared the the 5.0 coyote its just not as smooth, it finally caught on at 60km/hr and started hauling and accelerated with even power. If it is the cylinder deactivation, is there any way to disengage it?

Thanks in advance

I have the 5.7 Hemi with etorque and the acceleration is great with smooth shifting. Absolutely no lag issues. It pins you back in the seat when you nail the accelerator.

 

[C.E.Divine]

I got my new 2019 nearly as soon as it was backed off the delivery truck. The first 250 miles were rough, and I though I had made a terrible mistake. Acceleration was terrible. I felt like I was going to have to put my foot through the firewall to get it to accelerate. It was bogging down something godawful. But as it has started to wear in and learn my habits, it has started to clear up into a sweet driving truck. You can't even feel the shifts, and the accelerator feels like an extension of my will. Buy one and it will learn you. You won't regret it.

 

[MJP]

I got my new 2019 nearly as soon as it was backed off the delivery truck. The first 250 miles were rough, and I though I had made a terrible mistake. Acceleration was terrible. I felt like I was going to have to put my foot through the firewall to get it to accelerate. It was bogging down something godawful. But as it has started to wear in and learn my habits, it has started to clear up into a sweet driving truck. You can't even feel the shifts, and the accelerator feels like an extension of my will. Buy one and it will learn you. You won't regret it.

Glad yours is coming around. I must have lucked out. I was always very impressed with the accelaeration.

 

[Gman]

I like that a lot of owners use the word "effortless" to describe the hemi's acceleration.

I think this word comes to mind in that I feel no vibration from the engine. Other than the exhaust note, there's really no 'drama' when I put my foot down.

 

[AnthonyD1978]

Perhaps that truck has been beat-up during test drives and is now having issues. I have some pretty good experience with this transmission in my BMW. RPM and launch control are limited in that car until after break-in procedure is performed. This transmission is bullet proof if properly broken-in.

My only issue with the RAM is how they program the throttle mapping. Where it's dead for the first 20% of the throttle.

 

[Jp306]

I'm probably wrong, but mine would feel like that if the rears lost traction and the TCS kicked on and cut power to the wheels. Then it would take a second to get that power going again. Maybe you were breaking loose a bit?? Just a thought.

 

[HoosierTrooper]

I'm probably wrong, but mine would feel like that if the rears lost traction and the TCS kicked on and cut power to the wheels. Then it would take a second to get that power going again. Maybe you were breaking loose a bit?? Just a thought.

This topic was started almost 2.5 years ago and the op hasn’t been back since then. I’m guessing he’s moved on and forgot all about it.

 

[Jp306]

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