Xcalliber

Xcalliber Xcalliber has specialized in repairing, replacing, and upgrading Allison transmissions since 1984 and offers a full line of stock and performance parts.

Whether you have a GM Duramax truck or a fleet of commercial vehicles, Xcalliber has you covered.

The ONLY American-made performance hubs, carriers, and shafts come from Xcalliber. Upgrade your Allison transmission and...
04/10/2026

The ONLY American-made performance hubs, carriers, and shafts come from Xcalliber.

Upgrade your Allison transmission and keep it American. Get your billet parts at XCALLIBER.COM. 🇺🇸


We’re proud to share this kind recognition from Veterans Park Elementary. We’re always happy to support our local school...
02/27/2026

We’re proud to share this kind recognition from Veterans Park Elementary. We’re always happy to support our local schools.

Customize a renewed Allison 1000 transmission for your GM Duramax pickup — LB7, LLY, LBZ, LMM, LML, or L5P.Renewed stock...
01/05/2026

Customize a renewed Allison 1000 transmission for your GM Duramax pickup — LB7, LLY, LBZ, LMM, LML, or L5P.

Renewed stock transmissions are in stock and ready to ship, and performance models are available from 500–2,000 HP.

Features and Benefits:

• Dyno-tested — In stock, ready to ship
• Complete with the latest upgrades
• Contains the most new parts in the industry
• New coolers in stock
• ATF in stock
• Free return freight on core (continental U.S.)

To order your renewed Allison transmission, call 800.682.1290, email [email protected], or customize your build online by clicking here:
https://www.xcallibertransmission.com/renewed-allison-transmissions/

Xcalliber’s renewed Allison transmissions are in stock and ready to ship.Available Series:• Allison 1000 / 2000 / 2500• ...
01/05/2026

Xcalliber’s renewed Allison transmissions are in stock and ready to ship.

Available Series:

• Allison 1000 / 2000 / 2500
• Allison MD3000 / B400 / T200
• Allison HD4000 / B500 / T400
• Legacy transmissions (AT / MT / HT)

Features and Benefits:

• Dyno-tested — In stock, ready to ship
• Complete with the latest upgrades
• Contains the most new parts in the industry
• New coolers and cooler kits in stock
• Yokes in stock
• Flywheels and ring gears in stock
• TCMs and shift selectors in stock
• Free return freight on core (continental U.S.)

To order your renewed Allison transmission, call 800.682.1290, email [email protected], or request a quote by clicking here:
https://www.xcallibertransmission.com/renewed-allison-transmissions/

There’s still tread left on the tire…So we’ve extended our Black Friday Sale for today only. Shop Xcalliber.com now to s...
12/01/2025

There’s still tread left on the tire…

So we’ve extended our Black Friday Sale for today only. Shop Xcalliber.com now to save on performance parts for your Allison transmission.

🏁 SAVE 10% on Allison performance upgrade kits 🏁
• 29545311-X
• 29545311-XX
• 29545311-###
• 29545312-X
• 29545312-XX
• 29545312-###
• 29547606-X
• 29547606-XX
• 29547606-###
• CL1000-XX

🏁 SAVE 15% on all Allison performance upgrade billet shafts 🏁
• 29539506-X
• 29548947-X
• 24281105-X
• 29536984-X
• 29546284-X
• 29531252-X
• 29547444-X
• HPSHAFTKIT-L5P-X
• HPSHAFTKIT-LML-X
• HPSHAFTKIT-X

🏁 SAVE 20% on the below Allison performance billet hard parts 🏁
• 29544804-X
• 29546705-X
• 29546706-X

XCALLIBER.COM

Platinum and Black Dealer discounts will be applied.

Valid now through midnight, December 1, 2025. Performance part numbers must end in "X" to qualify. Cannot be combined with other offers. While supplies last.

Your Allison transmission needs this sale…🏁 SAVE 10% on Allison performance upgrade kits 🏁 • 29545311-X• 29545311-XX• 29...
11/27/2025

Your Allison transmission needs this sale…

🏁 SAVE 10% on Allison performance upgrade kits 🏁
• 29545311-X
• 29545311-XX
• 29545311-###
• 29545312-X
• 29545312-XX
• 29545312-###
• 29547606-X
• 29547606-XX
• 29547606-###
• CL1000-XX

🏁 SAVE 15% on all Allison performance upgrade billet shafts 🏁
• 29539506-X
• 29548947-X
• 24281105-X
• 29536984-X
• 29546284-X
• 29531252-X
• 29547444-X
• HPSHAFTKIT-L5P-X
• HPSHAFTKIT-LML-X
• HPSHAFTKIT-X

🏁 SAVE 20% on the below Allison performance billet hard parts 🏁
• 29544804-X
• 29546705-X
• 29546706-X

Shop XCALLIBER.COM now.

Platinum and Black Dealer discounts will be applied.

Valid Thursday, November 27 through midnight, November 30, 2025. Performance part numbers must end in "X" to qualify. Cannot be combined with other offers. While supplies last.

We’re thankful for our customers — and wish you all a happy, healthy, and epic Thanksgiving feast.We’ll be closed on Nov...
11/24/2025

We’re thankful for our customers — and wish you all a happy, healthy, and epic Thanksgiving feast.

We’ll be closed on November 27 + 28.


🥧 Xcalliber.com 🦃


11/11/2025

Everything we have today is thanks to our Veterans.

We’re proud of our country and grateful to all those who served.

09/16/2025

Introducing our EPC (Electronic Main Pressure Control) blocker for GM 6.6L Duramax (LML/L5P) 2011–2020 6-speed trucks equipped with Allison 1000 transmissions for addressing the issue of low mainline pressure.

The purpose of this EPC solenoid in the Allison 1000 transmission is to regulate mainline pressure, which is generated by the transmission's oil pump and directed by the valve body to the clutch packs. The stock pressure is between 80 psi (normal driving) and 230 psi (during shifts). At 80 psi, the clutch packs may not have enough clamping force to handle the engine's torque, particularly under heavy loads or with aftermarket upgrades, leading to slippage, excessive heat, and clutch damage. The EPC Blocker ensures consistent high pressure (up to 230 psi) to improve holding power. The EPC blocker bypasses the solenoid's pressure modulation, allowing the transmission to maintain maximum mainline pressure at all times. This eliminates the pressure drop to 80 psi after shifts, providing stronger and quicker clutch clamping and improved shift quality.

The benefits of this EPC blocker:
• Improved shift quality for firmer, more positive shifts due to consistent high pressure
• Increased clutch holding power supports higher horsepower and torque, ideal for modified trucks or heavy towing
• Extended transmission life by reducing clutch slippage, minimizing heat buildup on clutch pack material
• Simple installation requires only draining the transmission fluid, removing the oil pan, and installing the blocker without needing to remove the valve body

Click here to order your EPC blocker:
https://www.xcallibertransmission.com/product/epc-x/

The transmission runs. The colors don’t. 🇺🇸HAPPY LABOR DAY from everyone at Xcalliber.We’ll be closed Friday, August 29 ...
08/27/2025

The transmission runs. The colors don’t. 🇺🇸

HAPPY LABOR DAY from everyone at Xcalliber.

We’ll be closed Friday, August 29 — Monday, September 1.

07/10/2025

We’ve designed an innovative solution to address the most common failure in 10L1000 Allison transmissions. Over time, the clutches can tear through the splines of the stock F clutch drum. To address this, we’ve developed and manufactured a performance F clutch drum with a steel-splined insert — delivering unmatched durability, even under extreme performance applications.

GET THE UPGRADE
https://www.xcallibertransmission.com/product/24048634-x-r-2/

Address

115 Commerce Road
Brookfield, CT
06804

Opening Hours

Monday 8am - 5pm
Tuesday 8am - 5pm
Wednesday 8am - 5pm
Thursday 8am - 5pm
Friday 8am - 4:30pm

Telephone

+18006821290

Website

https://xcalliber.com/

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