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Have you ever wondered why your transmission and/or jeep as felt sluggish more specifically the 2016+ years.
I’ve discovered the FCA has been limiting the max torque that the engine will output as a result of torque management from the TCM on 2016 vehicles and presumable all 2016+ Cherokees and Chrysler 200 vehicles.

There are torque management values in both the PCM (Engine) and TCM (transmission) that are set at values to preserve the drive-train, which make sense. What was rather shocking is that the values in the TCM were LESS than what the engine could make.

I have read 2 2016 Cherokee TCMS and both had the lower than factory torque values programmed in the TCM. I”ve also read a 2016 Chrysler 200 FWD 3.6L and its low torque values were EXACTLY the same as what was in my Cherokee TCM.

To recap the 3.2 Pentastar has a torque peak of 239ft/lbs @ 4400rpm
The 3.6 Pentastar in the Chrysler 200 has a torque peak of 262ft/lbs @ 4250rpm

2016 Cherokee TCM torque limit


2016 Chrysler 200 3.6 V6 FWD TCM Limit



Notice how the are exatly the same, super odd....

The first version of my TCM tune had the values restored to "stock like" values




After getting my TCM tuned the factory torque values were put in. This made the vehicle feel much stronger as the vehicle was allowed to make more torque than what it was before. Since I was modified and making more torque than factory, I needed to raise the values higher. I did some further testing and moved up the values even higher to a point that would be higher than my engine would ever produce effectively letting the engine make as much power as It could without being restrained shown below.



The results were very impressive, it literally felt like I had gained another 50hp (I didn’t in reality) but the vehicle launched much harder, downshifts were quicker and the power came on even faster than before. Sadly I was not able to run at the track after these changes due to it being rained out. In terms of times I’m not sure it would have been much faster ET wise but the driving experience was even better.

Now there were a few things I noticed after changing the values much higher. Normally under regular driving I would never really “feel” the upshifts or downshifts. With the values much higher there was a noticeable engagement of the gears and downshifts sometimes gave a hard thud that shook the whole vehicle. Most likely one of the reasons why FCA programmed them the way they did.

What about 2014 and 2015 models? My 2014 Cherokee has always shifted harder and more firm. Prior to my TCM tune on my 2016 I always wished my 2016 would shift like the 2014 did at WOT, it’s always quick and firm. When you take a look at the 2014 and 2015 TCM’s vs the 2016 and up TCM’s there is no option to adjust engine torque parameters in the TCM(like the 2016 and up models). There have been multiple software versions of HP Tuners but for 2014/2015 engine torque is still not adjustable. It may be that these models of transmissions aren’t limiting as much power as subsequent years. One obvious difference between the 2014 and 2016 is the shift pressures on 2014/2015 models are higher than 2016+ vehicles. Additionally torque converter apply/release values are much higher as well. Just a small example of the many Torque converter values that are higher on the 2014 vs 2016



What does it all mean? Probably nothing but I can tell you that after making the adjustments there was a very noticeable difference. I’d just really like to know why they have this torque management built in to the TCM programming. Maybe the higher failure rates of 2014/2015 models could be a result of more aggressive programming?

Also of note there is ZERO of that torque management in the ZF8 in my Grand Cherokee that reduces power below the peak torque of the engine
 

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Thanks always for the information you share. I never would have thought that engine power would be limited like that.

Sent from my Pixel 2 using Tapatalk
 

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Seems to me that if you can't get a transmission to shift smooth and last long, you limit the power going to it until it meets the criteria you're looking for. It appears thats what fca is doing here.
 

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Discussion Starter #4
Seems to me that if you can't get a transmission to shift smooth and last long, you limit the power going to it until it meets the criteria you're looking for. It appears thats what fca is doing here.
Most likely, but the torque limit of the transmission is 354ft/lbs, so why limit engine torque wayyyy below what the torque peaks are on the 3.2 and 3.6 engines?

At this point the only reason a Chrysler 200 is faster than a cherokee is because of the 600lbs of so of less weight. Yes it has a more powerful engine but it's limited exactly the same way the 3.2 is.
 

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Most likely, but the torque limit of the transmission is 354ft/lbs, so why limit engine torque wayyyy below what the torque peaks are on the 3.2 and 3.6 engines?

At this point the only reason a Chrysler 200 is faster than a cherokee is because of the 600lbs of so of less weight. Yes it has a more powerful engine but it's limited exactly the same way the 3.2 is.
It might have a 354ft/lbs limit, but that doesn't mean it'll perform flawlessly anywhere near that theoretical number. Detune until she runs smooth! Probably a city mpg bonus limiting hp in the first few gears too, for heavy footers anyway.
 

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Discussion Starter #6
It might have a 354ft/lbs limit, but that doesn't mean it'll perform flawlessly anywhere near that theoretical number. Detune until she runs smooth! Probably a city mpg bonus limiting hp in the first few gears too, for heavy footers anyway.
So the 516ft/lb limit of the ZF8 in my WK2 is way above the 390ft/lbs the engine makes, yet its not limited in torque below what the engine can make under normal driving conditions. In 4-low there is some torque reduction but nothing compared to the Cherokee KLs
 

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So the 516ft/lb limit of the ZF8 in my WK2 is way above the 390ft/lbs the engine makes, yet its not limited in torque below what the engine can make under normal driving conditions. In 4-low there is some torque reduction but nothing compared to the Cherokee KLs
zf8 just works better. No need for tq reduction as it hit the mark for durability and drive-ability at the current tq level with that engine.
 

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zf8 just works better. No need for tq reduction as it hit the mark for durability and drive-ability at the current tq level with that engine.

This would be my guess. FCA has to sell cars to the general public so they set durability and drive-ability standards based on that and have to match or exceed competitors vehicles statistics in those areas. Knowledgeable performance enthusiasts are willing to and expect to have to perform more maintenance and possibly have issues sooner. The general public might or might not enjoy better performance but if durability and drive-ability issues happened sooner with FCA vehicles it would negatively impact sales.
 

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Probably a stupid question, but if they are limiting it wouldn't they have to disclose this as they use HP/Torque in marketing literature? The 2016 eBrocure on jeep.com com lists 239 SAE lb-ft at 4,400 RPM for the 3.2L V6. I know things like top speed (governor limited) are common but I don't recall any such notice for torque.

Not that I personally care, this wasn't a factor in me choosing a Cherokee after all and I'd much rather have something reliable than the alternative. I do know that some people get bent out of shape over things like this though. ;)
 

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Probably a stupid question, but if they are limiting it wouldn't they have to disclose this as they use HP/Torque in marketing literature? The 2016 eBrocure on jeep.com com lists 239 SAE lb-ft at 4,400 RPM for the 3.2L V6. I know things like top speed (governor limited) are common but I don't recall any such notice for torque.

Not that I personally care, this wasn't a factor in me choosing a Cherokee after all and I'd much rather have something reliable than the alternative. I do know that some people get bent out of shape over things like this though. ;)
I was wondering that too. By limiting the engine torque compared to what is advertised, wouldn't that be construed as false advertising, and thus could be grounds for a lawsuit?
 

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I was wondering that too. By limiting the engine torque compared to what is advertised, wouldn't that be construed as false advertising, and thus could be grounds for a lawsuit?
Possibly, yes.
 

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Discussion Starter #14
I was wondering that too. By limiting the engine torque compared to what is advertised, wouldn't that be construed as false advertising, and thus could be grounds for a lawsuit?
What's interesting is the TCM torque limiting values do not appear in the TCM software in 2014/2015 models its only a 2016+ thing.
 

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I wonder if the latest recall is to fix that oversight. :dodgy:
Unlikely FCA isn't ever going to change the programming that drastic. Sort of like how they aren't going to give 3-2-1 shifting back on the vehicles that had it taken away
 

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Unlikely FCA isn't ever going to change the programming that drastic. Sort of like how they aren't going to give 3-2-1 shifting back on the vehicles that had it taken away
If that's their attitude, then so be it. I'll force the transmission to downshift in that case. Ha! Try, and stop me now, FCA! BWAHAHAHA!!!!
 
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Seems to me that if you can't get a transmission to shift smooth and last long, you limit the power going to it until it meets the criteria you're looking for. It appears thats what fca is doing here.

They did the same thing with the KJ (Liberty) Diesel as the autos couldn't handle the power.
 

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Torque management is popular across the board for vehicle manufacturers to extend the life of powertrain components, typically the transmission. I had a 2006 Silverado 2500HD with a 6L gas engine for a long time. If you could get the rear wheels spinning, you could hear an audible decrease in the engine until the wheels hooked back up. Aftermarket programmers could remove the torque management, which then led to drivers grenading their transmissions.
 

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Torque management is popular across the board for vehicle manufacturers to extend the life of powertrain components, typically the transmission. I had a 2006 Silverado 2500HD with a 6L gas engine for a long time. If you could get the rear wheels spinning, you could hear an audible decrease in the engine until the wheels hooked back up. Aftermarket programmers could remove the torque management, which then led to drivers grenading their transmissions.
Since the mid 90's (that I know of) manufacturers have been torque limiting. Especially at shifts. This is nothing new at all. As mentioned, even if trans is good for it, the PTU and other parts might not be. It's not like we have a Detroit Locker or a Ford 9 bolt in the rear end LOL. >:D

https://www.hotrod.com/articles/12-bolt-chevy-vs-9-inch-ford/
 
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