Transmision knock sound and engaugement

[J_0ne]

I have noticed a couple of things that I had not experince with prior vehicles:
1. A knock sound not very loud but firm when shifting from P/N to R or D.

2. While driving I noticed the engine sticks to the auto trans to the point that it feels like engine breaking. If I move it from D to N while driving the truck just glides naturaly as if I had a manual and hit the clutch otherwise the engine drags the vehicle down whith the rpm.

Are these 2 condition normal on Jeeps?

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[DailyMoparGuy]

I’ve noticed both. I experienced the knock going P/R to D in both of my prior vehicles with this 8 SPD (Charger RT and Ram 1500). However, the Gladiator knock is way more pronounced than the other two were.

The engine braking feeling is a first for me in this Gladiator. Especially at low speeds in traffic, it gets kinda annoying. Alternatively I had a weird but kinda cool experience when going down a very long and steep bridge in Lake Charles, LA. Anyone that’s been there knows the exact one I’m talking about…any way, while NOT in cruise control, 55-60 mph down this steep bridge, the truck held speed on its own to the dot…again, no brakes applied and no cruise control.

I think this 8 speed auto and programming just tries to do a lot without human input. Not sure though, hopefully someone more knowledgeable has an explanation.

 

[Jeepin' John]

Engine braking is normal - injectors cut off and you're getting better fuel economy

i have the PRND thunk as well. I've found that when the jeep is cold, you're in park and want to shift to reverse (like backing out of the garage), first shift to D at a "medium" speed with the lever, let it engage, and then to R, and mine does not knock. Now i do it all the time subconsciously. Once the trans warms up, i don't find it to be a problem.

 

[DAVECS1]

The knock is the Torque reserve and min throttle voltage, working against each other especially when the vehicle is cold. Your foot is in no way connected to the throttle. The transmission is not as much to blame as the Throttle body control is. The engine takes your foot input, the transmission input and the stability control input and then decides how much air it is going to let into the engine. The clunk is the reserve torque is set high. I have tried lowering it, but then the engine stumbles around when put in gear. Not long, but for a bit and it is not appealing. You can lower the first gear engagement pressure in the transmission and make it silky smooth, but I am not sure if that is good cor long term clutch health or it will present a problem, from a standing start. There are different tables for torque reserve in park and neutral as opppsed to drive, but both need adjust to quell the clunk. Last but not least the 3.6 8 speed combo relies alot on the 8 speed's agression shift adaptation programming, way more than the 8 cylinder variants. It uses a fair bit of the acceleration sensors in the stability control and speed and pedal inputs to select a shift schedule. The selection are pretty agressive even at 0. My guess is they are try to itiloze all the 3.6L has to make it feel peppy. In my opinion it makes it a bit of a geek when trying to drive calmly in normal traffic and slow situations. When I did the supercharger tunning I actually had to back alot of the stock programming way off, to utilize the newfound power.

 

[tommyp]

The knock is the Torque reserve and min throttle voltage, working against each other especially when the vehicle is cold. Your foot is in no way connected to the throttle. The transmission is not as much to blame as the Throttle body control is. The engine takes your foot input, the transmission input and the stability control input and then decides how much air it is going to let into the engine. The clunk is the reserve torque is set high. I have tried lowering it, but then the engine stumbles around when put in gear. Not long, but for a bit and it is not appealing. You can lower the first gear engagement pressure in the transmission and make it silky smooth, but I am not sure if that is good cor long term clutch health or it will present a problem, from a standing start. There are different tables for torque reserve in park and neutral as opppsed to drive, but both need adjust to quell the clunk. Last but not least the 3.6 8 speed combo relies alot on the 8 speed's agression shift adaptation programming, way more than the 8 cylinder variants. It uses a fair bit of the acceleration sensors in the stability control and speed and pedal inputs to select a shift schedule. The selection are pretty agressive even at 0. My guess is they are try to itiloze all the 3.6L has to make it feel peppy. In my opinion it makes it a bit of a geek when trying to drive calmly in normal traffic and slow situations. When I did the supercharger tunning I actually had to back alot of the stock programming way off, to utilize the newfound power.

What did you use to tune? Hp tuners?

 

[JWGladiator]

The knock is the Torque reserve and min throttle voltage, working against each other especially when the vehicle is cold. Your foot is in no way connected to the throttle. The transmission is not as much to blame as the Throttle body control is. The engine takes your foot input, the transmission input and the stability control input and then decides how much air it is going to let into the engine. The clunk is the reserve torque is set high. I have tried lowering it, but then the engine stumbles around when put in gear. Not long, but for a bit and it is not appealing. You can lower the first gear engagement pressure in the transmission and make it silky smooth, but I am not sure if that is good cor long term clutch health or it will present a problem, from a standing start. There are different tables for torque reserve in park and neutral as opppsed to drive, but both need adjust to quell the clunk. Last but not least the 3.6 8 speed combo relies alot on the 8 speed's agression shift adaptation programming, way more than the 8 cylinder variants. It uses a fair bit of the acceleration sensors in the stability control and speed and pedal inputs to select a shift schedule. The selection are pretty agressive even at 0. My guess is they are try to itiloze all the 3.6L has to make it feel peppy. In my opinion it makes it a bit of a geek when trying to drive calmly in normal traffic and slow situations. When I did the supercharger tunning I actually had to back alot of the stock programming way off, to utilize the newfound power.

Dave- excellent info as always.

would adding something like Pedal commander to the equation to limit the throttle forced “peppy-ness” ie setting the pedal to a low city setting- help limit some of the clunk potential in normal traffic and slow situations?

 

[DAVECS1]

Dave- excellent info as always.

would adding something like Pedal commander to the equation to limit the throttle forced “peppy-ness” ie setting the pedal to a low city setting- help limit some of the clunk potential in normal traffic and slow situations?

It may. In my current revision of the SC tune I have been able to dial the what is called the torque reserve way back and it has made a noticeable improvement. With a pedal commander it is a global change if it can get you rolling ng at a lower rpm u have a shot, but if the min pedal position you can get still has a high torque reserve it will probably be clunky still

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