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Arrington Performance Transmission Solutions

ShopHEMI now offers a full lineup of Arrington Performance transmission solutions. Each HEMI transmission is purpose built by NAG1 specialists to maximize the performance of your specific vehicle, power output, and engine type. We have race and street proven NAG1 setups designed for HEMI engines with Twin screws superchargers, centrifugal superchargers, turbochargers, NA stroker internals, and bolt-on modifications.

HEMI Valve Body

What Is A Valve Body?

A valve body is the hydraulic control center of your automatic transmission. Most of these valves operate automatically, except for the manual valve which is controlled by the gear shift selector. When you move the handle from park to drive or reverse the manual valve mechanism covers a specific series of maze-like hydraulic passages, while leaving other sequences uncovered. For example, when your Dodge, Chrysler, or Jeep is put into drive, the manual valve sets the hydraulic sequence to direct fluid to the clutch packs or band servos that the transmission needs in order to engage first gear. Simultaneously, the transmission control components monitor your vehicle's throttle position and speed, to determine both shift timing and firmness for the enviable first to second shift.

Valve Body Electrical Solenoids

Modern transmissions also have electrical solenoids that are attached to the valve body with the job of directing fluid to the appropriate clutch packs or bands. These solenoids are under direct control by the engine control unit(ECU) or transmission control unit(TCU), with the goal of more precisely controlling the transmission's shift points than could be accomplished without the assistance of the computer.

Valve Body Operation

When you put your vehicle in gear and drive your car, the valve body, in conjunction with other gear box components, senses the engine RPM and the vehicle speed and directs the pressure to various hydraulic pathways that control the valves that drive the transmissions various clutch and brake band actuators. The result of this action is that the gear ratio for the planetary gearset is optimized so that it selects the optimum gear ratio for the current operating conditions. For example, the 3-4 shift valve activates the 3nd gear to 4rd gear for when the car needs to up-shift or the 4-3 shift timing valve which determines when the transmission downshifts.

Why Upgrade A HEMI Valve Body?

Both the Arrington Performance Stage 1 and Stage 2 transmission upgrades focus on upgrading the NAG1 valve body. Arrington starts by upgrading the valve body because it has such a large impact on transmission performance. After upgrading your NAG1 valve body, you will notice that the more aggressively you accelerate your LX or LC Challenger, the firmer your gear box will shift. Arrington Stage 1 valve body gives you firmer than stock downshifts, without being harsh. However, the Stage 2 valve body, with its blue top solenoids, produces very firm downshifts. Simply put, an upgraded valve body makes your HEMI transmission accelerate faster, by eliminating the weak stock shifts and replacing them in favor of firm, high performance shifts. The subsequent staged upgrades beyond Stage 2 also include the Stage 2 valve body upgrade.

HEMI Transmissions

Why Upgrade A HEMI Transmission?

The most common reason that people decide to upgrade their HEMI transmission is that they have increased the power output of their motor beyond what their stock transmission can handle. The stock NAG1 gear box has its power limits, just like any other OEM trans. The more power your HEMI engine produces the more likely that your clutch packs and other critical transmission components will wear prematurely and cause a gear box failure. Of course, some people will manage to put down impressive dyno numbers and low ET's without the benefit of performance transmission upgrades; unfortunately, it's just a matter of time before many of these will require a complete transmission rebuild. Although transmission modifications are not inexpensive, consider the cost of rebuilding a blown up gear box- without the benefit of a good core to offer in exchange for your new unit.

Do I Need To Upgrade My HEMI Transmission?

Another common question HEMI enthusiasts often ask is, how much power can the stock transmission take before I need to beef it up? Due to the fact that each car and driver is different, there is not a definitive, one size fits all, answer for all cases. Obviously, if you drive your car conservatively it is likely that the transmission will last longer than someone who runs a lot of passes at the local drag strip. Undoubtedly, you did not buy a 5.7 / 6.1 HEMI powered Challenger, Charger, or Jeep SRT-8 in order to poke around. The rule of thumb for a typical Challenger, Charger, Magnum, or 300c is that above 450 rear wheel horsepower is the point at which you should think about upgrading the NAG1 transmission. An all-wheel drive Jeep SRT-8 transmission passes the safe zone at around 400 AWHP.

NAG1 Transmission Upgrade Advantages

There are other advantages to upgrading your NAG1 transmission, besides increasing your car's durability and reliability. Transmission upgrades increase shifting firmness, speed, and efficiency which leads to faster acceleration. Another advantage is that the line of Arrington Performance Transmission Solutions can be specifically tailored your HEMI engines power output. An upgraded transmission can also give your car more consistent ET, which is key for drag racing.

HEMI Torque Converter

How A Torque Converter Works

While cars with a manual transmission have a clutch to disconnect the engine from the gear box, cars equipped an automatic transmission use a torque converter instead. In the simplest terms, a torque converter a fluid coupling that allows the car's engine and transmission to operate at different speeds. It does this by varying the torque that is transferred to the transmission. When the car is stopped(still in drive), only a small amount of torque is applied so that the car can be held in place with only modest breaking force. Then, the torque converter fills with fluid and allows more torque to pass through to the transmission, causing the car to accelerate as the wheels receive more power.

HEMI Performance Torque Converter

The NAG1's torque converter can also be specifically tailored to match your HEMI engine's specifications. By selecting the proper torque converter for your car, the Arrington Performance Transmission Solutions product line helps your motor to effectively transfer its power to the wheels. If you have a twin screw Kenne Belle or Magnuson supercharger, we suggest a NAG1 D 3000 Stall Torque Converter that is optimized to control the excessive wheel spin that twin screw superchargers produce. However, if you have a Procharger Centrifugal supercharger, or twin turbos, or a NA Stroker motor, you should go with a NAG1 A 3500 Stall Torque Converter. The NAG1 AE 4500+ Extreme Stall Torque Converter is suggested for cars with aluminum stroker motors. This customized approach makes it easy to get the most out of your 5.7L or 6.1L, no-mater if its supercharged, turbocharged, stroked, or stock.

Arrington Performance Transmission Solutions

HEMI NAG1 Stage 1 – Upgraded Valve Body

Specifications
  • The Stage II modified valve body increases shift pressures. (Increased Firmness)
  • More Aggressive Driving Produces a Firmer Shift
  • Firm but not Harsh Downshift
  • Full One Year Warranty Regardless of Power Applied
  • Designed using a test NAG1 that monitored all clutch pressures, torque converter pressures, and torque converter lock up clutch pressures with accurate analog gauges.
Included Upgrades
  • Stage II Valve body
Applications
  • Stock vehicles
  • NA LX / LC up to 450 RWHP
  • NA Jeeps up to 400 AWHP

HEMI NAG1 Stage 2 – Upgraded Valve Body and Blue Top Solenoids

Included Upgrades
  • Stage II Valve body
  • Blue Top solenoids(VERY firm downshift)
Applications
  • Stock vehicles

HEMI NAG1 Stage 3 – Performance Built Transmission

Included Upgrades
  • Stage II Valve Body
  • High performance double sided forward Mercedes clutches
  • Mercedes seals
  • Mercedes gaskets
  • Mercedes oil filter
Applications
  • Stock vehicles
  • NA LX / LC up to 550 RWHP
  • NA Jeeps up to 475 AWHP

HEMI NAG1 Stage 4 – High Performance Built Transmission

Included Upgrades
  • Stage II Valve Body
  • High performance double sided forward Mercedes clutches
  • Mercedes seals
  • Mercedes gaskets
  • Mercedes oil filter
  • Blue Top solenoids(VERY firm downshift)
Applications
  • Stock vehicles
  • NA LX / LC up to 650 RWHP
  • NA Jeeps up to 525 AWHP

HEMI NAG1 Stage 5 – Extreme Performance Built Transmission

Included Upgrades
  • Extreme performance transmission
Applications
  • Extreme Horsepower vehicles

HEMI NAG1 D 3000 Stall Torque Converter for Twin Screw Supercharged Vehicles

Applications
  • Twin screw (Kenne Belle, Magnuson) supercharged vehicles ONLY.
Specifications
  • This converter is specially designed to control excessive tire spin

HEMI NAG1 A 3500 Stall Torque Converter for NA Stroker HEMI or Centrifugal Superchargers

Applications
  • Approximate 3500 + stall on a stroker
  • Turbos
  • NA Stroker
  • Centrifugal superchargers (Procharger, Vortech etc.)

HEMI NAG1 AE 4500+ Extreme Stall Torque Converter

Applications
  • Approximate 4500 ++ Ultra high stall on an aluminum stroker

Arrington Performance NAG1 HEMI Flex Plate with ARP Bolts

Applications
  • All performance Gen III HEMIs with a NAG1
Specifications
  • High Strength Grade ARP Bolts
  • Mandatory in NHRA & IHRA Class racing
  • Certified to 12,500 rpm
  • Full warranty for 1 year!
  • Safety Rated / SFI 29.1 Certified Flex Plate