2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.
2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.
2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.
2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.
2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.
2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI.

2017 - 2023 GM 6.6L L5P Duramax | Transmission Tuning by PPEI


Extend your L5P Duramax's transmission's life and increase your fuel economy with PPEI's T87A/T93 Transmission tuning! A MUST for tuned trucks with additional torque.

PPEI was the first to offer transmission tuning for these new allisons and we have not let off the throttle since!

The refined shift points get rid of the low rpm “Lazy” feel these trucks have that force the driver to stab the throttle for a downshift – not cool and a fuel economy killer! For vehicles with larger turbochargers, ppei transmission tuning is a must to get the engine back into a rpm range to match the torque curve of the new turbo.

Along with the improved shift points, PPEI also refines the torque converter lockup strategy to put the power to the ground much more efficiently for improved fuel economy by eliminated unnecessary slip in the torque converter – which also drives down heat in typical “unlocked” conditions.

Lastly (and possibly the greatest benefit) is the increase in line pressure ppei provides. line pressure increases the holding capacity in the transmission by clamping the clutch packs together with more force – this allows tuned trucks (or trucks towing heavy) to have the confidence they need to enjoy their truck for years to come.

This tuning package can be installed using an PPEI RTD, HPTuners MPVI2/3.

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Customer Reviews

Based on 34 reviews
Adam Dozier
Not all the hype everyone states it is.

While the transmission tune is to extend the life of your transmission and help with holding gears longer for towing and not having so many downshifts, the reviews say you have a faster response on acceleration from a stop. They also say better fuel economy is to be expected in conjunction with the increase in transmission longevity. My truck is deleted already. People talk about a feel in the seat of your pants upgrade. Maybe they have a factory tune on their truck? I definitely didn't notice an increase in acceleration. I did notice a very minimal decrease in response time from pressing the gas pedal to the truck moving forward from a stop sign. Nothing to call worth the upgrade. I have a few gripes about it. I want to give a shoutout to Zack for his awesome customer service as we spoke several times on the phone. The instructions didn't work on my 2020 GMC Denali for the reading of the tune as well as writing the tune. Zack ended up helping me download the tune and also uploaded the tune remotely for me. The truck shifts a bit firmer at times but not all the time. It shifts way earlier than before. It almost feels like it skips 2nd gear sometimes. Also if you put the gas pedal on the floor to pass a vehicle it no longer downshifts and accelerates like it used to. Now it down shifts only 1 gear if at all before slowly lugging on passed a vehicle. Sometimes it doesn't even downshift and holds the gear with it on the floor. This was something mentioned for a positive when pulling a trailer but I don't want my truck to not be able to pass vehicles when needed or have the power to speed up and match traffic flow when merging. Overall I will rate the transmission tune itself as a 3. I'm really not too happy with it and feel like I could have spent the money somewhere else instead of this tune. I will give customer service to PPEI and the turnaround time for shipping a 5 star rating though. I felt like I was in good hands during the daunting task of trying to tune this truck.


Support was A+++ truck feels uncorked and more smooth!

David Nelson

Finally got to really drive my truck today. I noticed the torque converter doesn’t lock up in 2nd gear, is this normal. I thought PPEI tuning locked them in 2nd??? Secondly the truck seems to hunt gears between 45 mph and 55mph. Truck does shift quicker and crisper.

John Kenny
Awesome support

Got the tcm tune for my 2020 l5p !!! Tcm performs as advertised and the support is awesome, as it was my first time installing tuning i had a million questions which were answered quickly and very politely. Awesome job guys i appreciate the help along the way

Zachary todd
2023 DirtyMax Tcm Tune

I want to start off by saying think u PPEI for all the hard work , help , and knowledge . This tcm tune makes a daylight and dark difference , way faster shift points , 100 percent better throttle response , this turned my truck into a beast ..It’s super amazing at the power I’m able to put down compared to stock .. This is one mod I 100 percent recommend.. U did an amazing job guys I will buy more products in the future ..


PPEI, also known as Power Performance Enterprises, Inc., is led by the business owner and lead calibrator/tuner Kory Willis. PPEI began calibrating/tuning back in 2008, specializing in Diesel Performance but has since expanded into the Gas and Powersports industries. Kory and the team at PPEI have set many world records along with continuing many industry “firsts”. We take pride in knowing that Kory not only prides his work, but also thoroughly enjoys setting expectations high for our team so our customers can have the best products available in the world.