2024-2026 CHEVY / GMC L5P DURAMAX | GDP RTD4 TUNER | DPF DEF EGR DELETE KIT

GDP ECM Unlock + RTD4 Tune File(s) | 2024–2026 GM Duramax L5P 6.6L (BYO DPF DEF EGR DELETE KIT)

2024–2026 L5P Duramax tuning — done the correct way - READ BELOW!

The 2024–2026 L5P platform uses the E42 ECM, which must be upgraded/unlocked before you can flash custom tuning. This package covers the two required steps:

1. E42 ECM Upgrade/Unlock Service (mail-in + return label included)

2. GDP RTD4 tune file(s) delivered through their custom Tuners ecosystem.
   

What’s included

• GM E42 ECM Upgrade Service (Mail-in Unlock) — required first step to make the factory ECM tuning-ready

• GDP RTD4 ECM Tune File(s) — choose your power level or the Level 1–5 Multi Pack

• Speed limiter removed

Select your power level (single-level files — no SOTF)

Choose the file that matches your use, or grab the Multi Pack:

• Level 1 (Stock HP)

• Level 2 (+35 HP)

• Level 3 (+70 HP)

• Level 4 (+125 HP)

• Level 5 (+180 HP)

• Level 1–5 (Multi Pack)

Important: These are single-level tune files—no SOTF or alternate power levels at this time. TCM tuning requires TCM sent in and can be added below and requires additional credits and GDP tune. 

Key notes (read before ordering)

• VIN required before purchase, and you’ll complete a tuning form after the ECM upgrade/unlock

• CAN bus plugs not yet available — NOx & DEF CAN systems must remain plugged in or tied in place (DEF plug with modification on 2024 ONLY)

• Your truck must have an unlocked E42 ECM before flashing

How the E42 ECM upgrade/unlock works (mail-in service)

1. Place your order

2. You’ll receive instructions to send in your original ECM

3. The E42 upgrade is completed, then it ships back to you (3–5 business day processing time, shipping time not included)

ECM condition matters: no broken tabs/plastic; spare ECMs are not accepted—only the original ECM from your truck.

Requirements (hardware/software/credits included)

•  RTD4 required for the E42 upgrade path 

•  RTD4 VCM Suite (Beta)

• Tune file built for RTD4 and compatible with via TDN (Tune Delivery Network)

• Credits: expect 8 credits to license/flash (per the platform requirements)

• Optional add ons via menu buttons: EGR Delete Kit, DPF Delete Pipes or Full Exhaust, Cold Air Intake & Shibby Engineering Plug Kit.

Vehicle compatibility

• 2024–2026 Chevrolet Silverado HD 2500/3500 — 6.6L L5P

• 2024–2026 GMC Sierra HD 2500/3500 — 6.6L L5P

Returns / cancellations

Because this includes a mail-in ECM service and VIN-specific digital tuning, it should be treated as final sale once processed/delivered.