I don't think it's going to hurt the transmission, people have been running increased shift firmness for quite a while now and I haven't heard of any issues. I've been running increased shift firmness for about 2 and 1/2 years on my car, with many hard shifts and well over 100 quarter mile passes and I can report no problems so far.

 

Any time You alter a transmissions pressure higher then it was designed for, It's only a matter of time till it breaks something, and one day it'll be on a hook to get rebuilt plus hard parts! Dodge knows you can only go so far with a tuner, but with an actual shift kit installed you're pretty much not gonna be covered under warranty..and once it's been tuned that info stays in the black box and can not be erased it can only be accessed by dodge! According to my tech buddy at a dealer.

 

I don't think we are going to higher line pressures than the transmission was designed for. The same transmission with the Mercedes Blue top solenoids and valve body has a heck of a lot more power being run through it from the AMG and shifts much firmer than our Challengers. Bascially someone determined that Americans prefer mushy shifts to the hard hitting european shifts and short changed us on certain parts that would make our transmissions much more enjoyable for some of us.

Concerning line pressure, I don't know the numbers but Chrysler doesn't have them set at max pressure, so (again my opinon) but I don't think the increase is going to cause much problem. There is also the opinion that a quick shift generates less heat than a slow shift and heat is the bane of transmissions. There are some that believe that a good firm shifting transmission actually prolongs the life of the transmission.

Of course you should be aware of warranty issues when you start to mod for performance if that is a concern for you. Anytime one does any mod there are no doubt certain risks involved, in this case I believe it is fairly low. Since I'm used to driving and racing older muscle car's which have no warranty I don't generally think a lot about it. Mostly I figure if you break it you fix it and move on.

I'm not trying to make light of anyone for whom the warranty is a primary concern, but if it is then it would probably be best to not mod for performance.

Here's a link that will get you to a good article on what breaks at what horsepower ratings on our cars. http://www.challengerforumz.com/showthread.php?t=83965

 

First off, I don't think Chrysler can tell if your car has been tuned or not. Maybe in theory they can, but I would guess it would take some kind of computer-forensic expert to do this. In other words, the tech at your local dealer won't know its been tuned.

Second, I'm not sure what is going on to increase the shift firmness. Its my understanding there is torque management. In other words, when your car shifts, its backs down the power of the engine during the shift to help save the drive line. So are the shifts harder, or does the engine just not back down the power? I don't know the answer, but Diablo probably does.

Third. I suspect the harder shifts aren't that much harder on the tranny, but things like U-joints, drive shaft, rear gears, half shafts and such are.

 

I don't think it's going to hurt the transmission, people have been running increased shift firmness for quite a while now and I haven't heard of any issues. I've been running increased shift firmness for about 2 and 1/2 years on my car, with many hard shifts and well over 100 quarter mile passes and I can report no problems so far.

2x to what 70barcuda said