Hesitation in 3rd Gear at 2k RPM

[ShadowsPapa]

One dealer has said that it's normal and the transmission "rubber bands" meaning it'll alow slip and then slap itself back into gear;

Simple answer to that is "BULL CRAP".
No transmission slips then grabs. That's not how they work, nor should they because slipping clutches and/or bands means heat and wear. Clutch packs are applied - not instantly like "dumping a clutch" but with the aid of accumulators and so on that allow an even, although fairly quick, application of the clutch. it's handled by pumping fluid into the chamber behind the clutch pack piston squeezing the clutch disks and plates (an alternating sandwich) against each other until there's no slippage. Once applied, they stay applied.
Same for bands - a servo, a hydraulic piston, pushes the band around a drum, gripping the drum and stopping it from moving. it's a lot of force. So much force that I've seen the servo snapped off the case when a valve in the valve body locked or wedged because of a tiny piece of lint.

It would take time and their dedication and knowledge to do so, but they CAN actually diagnose a transmission every single step of the way including information gathering such as the time to engagement, pressure to the clutch pack, pressure holding the clutch pack and more. They can tell how much pressure is getting to almost anything and how long it's taking for a clutch or band to engage and if that pressure holds or drops off (indicating leaking seals, etc.)
But they've got to get the OK to do it since it would take time - and thus $$.

Even years ago before all of the electronics, I could monitor the fluid pressures to enough places in a transmission to tell you if a clutch pack or band was being applied, how much pressure was there, throttle pressure vs. governor pressure and more. Today it's all electronically monitored.
We had to unscrew plugs from the case and attach pressure gauges with long hoses. Today, plug it in and watch the numbers.

But the idea that anything "rubber bands" is a hoot. That's just silly.

And a torque converter doesn't act that way, either. It's either in torque multiplication phase where the "pump" fins on the shell are directing fluid through the turbine or it's stalled or locked.
There are actually decent videos out there on how a TC works, explanation of how various TCs lock, stall speeds and so on. Maybe those techs need to spend some time in the books again?

If I'm accelerating while in 3rd but below 2,000rpm, the truck bogs but then noticeably bucks a tiny bit like it just got dumped a ton of fuel into it.

If a gasser, that's lugging. They haven't got a narrow power band (it's actually pretty wide for a gas engine) but below 2,000 RPM is lugging territory, IMO. The only engine I ever let get below 2.000 RPM and try to accelerate is the 4.0 in my car because that baby can be at 1400 RPM in 3rd and accelerate up a hill and never flinch. But if my JT 3.6 was a stick, I'd not want to try it.
The gasser needs RPM to make torque and HP. It's not a great sub-2000 engine, IMO.
Diesel - that's another matter. Those love life in the lower RPMs

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[IzzyO]

Odd, have you had any more updates?

I just dropped mine off at 8901 miles for the 2nd check on the issue. I’m going to look into lemon laws here shortly to see if them saying “can’t replicate” counts or if they need to replicate it, document it, then try to fix it for it to count.

Yes, unfortunately. It has improved somewhat since I last posted, but it's still there on the low end. The advice is to basically drive it until it breaks unless you have time to waste at the dealership. The dealership apparently can't recreate the issue. So, I've got a year or 20,000 miles to figure it out or dump it.

 

[JTDay]

My MT gladiator also "hesitates" (it really feels like a soft misfire) around the 2k rpm range in 3rd gear and it does it again right before 3k. As another poster mentioned, I assume it's related to the throttle body and/or valve timing/lift settings in the ECU. It's a consistent phenomenon and I've never seen a CEL on a 22' with 25k miles. This may be different than what the OP is experiencing but since another MT driver posted on page 1, I'd thought I'd share that my truck mirrors that behavior he mentioned.

 

[ATL_Rubi]

Simple answer to that is "BULL CRAP".
No transmission slips then grabs. That's not how they work, nor should they because slipping clutches and/or bands means heat and wear. Clutch packs are applied - not instantly like "dumping a clutch" but with the aid of accumulators and so on that allow an even, although fairly quick, application of the clutch. it's handled by pumping fluid into the chamber behind the clutch pack piston squeezing the clutch disks and plates (an alternating sandwich) against each other until there's no slippage. Once applied, they stay applied.
Same for bands - a servo, a hydraulic piston, pushes the band around a drum, gripping the drum and stopping it from moving. it's a lot of force. So much force that I've seen the servo snapped off the case when a valve in the valve body locked or wedged because of a tiny piece of lint.

Agreed 100%. The dealer who claimed that is not the one the Jeep is currently at. I'm hopeful they'll recreate it, and get back to me. If not, I may ask to drive another 23 on the lot to see if it does it as well. I'll keep everyone updated.

Fun fact also, @ShadowsPapa , that update that the Jeep had about a month ago that we discussed on the lash adjusters therad is listed online under the service records as "Propeller Shaft"

Service record attached and Snip of online record attached.

 

[ShadowsPapa]

Agreed 100%. The dealer who claimed that is not the one the Jeep is currently at. I'm hopeful they'll recreate it, and get back to me. If not, I may ask to drive another 23 on the lot to see if it does it as well. I'll keep everyone updated.

Fun fact also, @ShadowsPapa , that update that the Jeep had about a month ago that we discussed on the lash adjusters therad is listed online under the service records as "Propeller Shaft"

Service record attached and Snip of online record attached.

Interesting.............

 

[ATL_Rubi]

Agreed 100%. The dealer who claimed that is not the one the Jeep is currently at. I'm hopeful they'll recreate it, and get back to me. If not, I may ask to drive another 23 on the lot to see if it does it as well. I'll keep everyone updated.

Fun fact also, @ShadowsPapa , that update that the Jeep had about a month ago that we discussed on the lash adjusters therad is listed online under the service records as "Propeller Shaft"

Service record attached and Snip of online record attached.

Jeep said no go, they cannot replicate the issue. I'll have to pick it up and won't be able to do anything about it unless it throws a code or gets worse.

 

[ATL_Rubi]

Jeep said no go, they cannot replicate the issue. I'll have to pick it up and won't be able to do anything about it unless it throws a code or gets worse.

Beginning to get some shudders at low RPM when inching along in traffic. Similar to a manual when you sort of depress the clutch with some gas to get going while already moving. Only below 3-5mph, and goes away after everything engages.

Also starting to notice some odd tendencies in reverse, hit it into reverse, give it gas, no movement then it'll kick in. WIsh I could get some sort of code to come up so the techs could at least give it a once over again. Might ask the SA if I can take him on a drive and try to replicate these issues.

 

[Dick]

Mine too, 300 miles, when coasting along, barely on the throttle, it seems to slip out of gear briefly then recovers and all is normal. Never happens when I'm on the throttle

 

[MiisterrZ]

Not to beat a dead horse but... have to wonder what became of this for you? or anyone else thats had this issue. Bought a 26' JT a little over a week ago and am experiencing these same symptoms. low speed, 3rd gear, bit of a 'clunk' then revs, 'fine' if youre gassing it through gears. unsure how this has been an ongoing issue and Stellantis just doesnt do jack about it...

 

[Dilly’S Willy]

Not to beat a dead horse but... have to wonder what became of this for you? or anyone else thats had this issue. Bought a 26' JT a little over a week ago and am experiencing these same symptoms. low speed, 3rd gear, bit of a 'clunk' then revs, 'fine' if youre gassing it through gears. unsure how this has been an ongoing issue and Stellantis just doesnt do jack about it...

I'm starting to think it has to do with emissions tuning. That's why the reflash fixed it. GM did this YEARS ago with Saturn. They programmed a "shift bump" to stop older customers from complaining it was "too smooth compared to previous vehicle".

Autos can have many factors for this compared to a manual.

Call the dealer and ask if your VIN has any tsb updates for software.

 

[MiisterrZ]

I'm starting to think it has to do with emissions tuning. That's why the reflash fixed it. GM did this YEARS ago with Saturn. They programmed a "shift bump" to stop older customers from complaining it was "too smooth compared to previous vehicle".

Autos can have many factors for this compared to a manual.

Call the dealer and ask if your VIN has any tsb updates for software.

oh i wouldnt doubt it, sad the 'reflash' fixed it for a short duration. seems it could be a 'd clutch pack' issue, so i wondered if OP ended up having to go the route of repair or? its going to the dealer on the 14th so we shall see.

 

[bmpcamry09]

I'm starting to think it has to do with emissions tuning. That's why the reflash fixed it. GM did this YEARS ago with Saturn. They programmed a "shift bump" to stop older customers from complaining it was "too smooth compared to previous vehicle".

Autos can have many factors for this compared to a manual.

Call the dealer and ask if your VIN has any tsb updates for software.

oh i wouldnt doubt it, sad the 'reflash' fixed it for a short duration. seems it could be a 'd clutch pack' issue, so i wondered if OP ended up having to go the route of repair or? its going to the dealer on the 14th so we shall see.

Check out my threads guys, I have fixed this, it's a tuning issue, and no, Jeep won't ever fix it, custom tuning is the only way to fix it. I have a way more detailed thread on the JL forum with tons of reviews and the like as well here. Long story short, it is erroneous VVL high lift activation and terrible cam schedules

https://www.jlwranglerforums.com/fo...26-jl-3-6-models-etorque-included-now.164496/

 

[bmpcamry09]

Not to beat a dead horse but... have to wonder what became of this for you? or anyone else thats had this issue. Bought a 26' JT a little over a week ago and am experiencing these same symptoms. low speed, 3rd gear, bit of a 'clunk' then revs, 'fine' if youre gassing it through gears. unsure how this has been an ongoing issue and Stellantis just doesnt do jack about it...

It's not a transmission issue, check out my threads on here and on the JL Wrangler forum, a well documented issue and I've been the only one able to come up with a real fix, Jeep won't ever release a fix for this because they would have to recertify with EPA which they won't do on a dated engine that is likely to be phased out next redesign.

https://www.jlwranglerforums.com/fo...26-jl-3-6-models-etorque-included-now.164496/

 

[bmpcamry09]

I'm not nearly as active on the JT forum, but I am wrapping up tuning for @danelizer as we speak and I’m sure he can vouch that the tuning transforms the truck, although his GPEC2A hesitation isn’t nearly as noticeable as the newer trucks, regardless, it gets addressed in all my files.

 

[Dilly’S Willy]

Check out my threads guys, I have fixed this, it's a tuning issue, and no, Jeep won't ever fix it, custom tuning is the only way to fix it. I have a way more detailed thread on the JL forum with tons of reviews and the like as well here. Long story short, it is erroneous VVL high lift activation and terrible cam schedules

https://www.jlwranglerforums.com/fo...26-jl-3-6-models-etorque-included-now.164496/

Figures. Just like their BS emissions tuning that forces the throttle to stay open for a couple seconds if you chop the throttle hard and let off. Super unsafe to force the vehicle to accelerate unless you push the clutch.

I do have plans for tuning in the future after my warranties run out in a couple years.

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