• Please fill out our Transmission Diagnostic Form (Be as detailed as possible).

  • If it is a SOUTHERN HOTROD LLC transmission, we will need the serial number. 
    NAG1 722.6 serial numbers are located on the driver side of the bell housing near the cooler line.
    8HP series serial numbers are located on the pan rail near the bell housing on the driver side.
    All SOUTHERN HOTROD LLC serial numbers are 5 digits.

  • Check your transmission fluid level and condition. LOW or HIGH fluid level can cause abnormal transmission operation.
  • Perform a full DTC "Diagnostic Trouble Code" scan and record ALL DTC's.

  • Verify that the Engine is mechanically sound and has a proper calibration.
    (Proper engine operation is essential for proper transmission operation).

  • Verify that there are no broken drive line components (i.e. Drive shaft, axles, differential)

  • ALL transmissions sent in for evaluation MUST have a RGA number assigned by SOUTHERN HOTROD LLC.

  • Send us a DATA LOG of the event, if possible. (HP Tuners or Diablosport)










Do I need torque management? Yes! Torque management is absolutely necessary for proper transmission operation.

Do I need a NEW torque converter with my NEW SHR transmission? Yes and NO. We always recommend a NEW torque converter with your NEW transmission. We have them for sale right HERE. At the VERY least, you will need to have your converter cut and cleaned by a professional torque converter builder. We can handle that for you if the need should arise. **NOTE** FAILURE TO EITHER REPLACE, OR CLEAN YOUR TORQUE CONVERTER CAN RESULT IN SERIOUS DAMAGE TO YOUR TRANSMISSION!!!

Do I need a custom transmission calibration? In most cases, yes. This will be dictated by your vehicle build and power level. 

Does my engine calibration affect my transmission operation? Yes! Poor engine calibrations can DESTROY your transmission rather quickly!

Does SOUTHERN HOTROD LLC tune transmissions? No. We do not. We focus on hardware. There are many qualified tuners available.

I have an 8HP 8 speed transmission equipped 2wd vehicle (Challenger, Charger, 300), should I install a single piece driveshaft? NO. We DO NOT recommend single piece driveshafts of ANY kind in 8HP 8 speed equipped vehicles. Vibrations and/or dynamic loads could cause CATASTROPHIC damage to your transmission. This could lead to Vehicle damage and/or personal injury. If you currently have one we recommend that you remove it. 

What transmission fluid do you recommend? SOUTHERN HOTROD LLC ONLY recommends MOPAR ATF+4 for NAG1 722.6, and MOPAR 8&9 Speed ATF for 8HP.

How much fluid does my NAG1 722.6 transmission take? 7.7 Liters (8.13 Quarts) Check and adjust as necessary.

How do I check the fluid level in my NAG1 722.6 transmission? You will need a NAG1 722.6 dip stick.

How much fluid does my 8HP transmission take? 8HP70/90/95- 9 Liters (9.5 quarts). Check and adjust as necessary.

How do I fill my 8HP transmission? CLICK HERE

How do I check the fluid level in my 8HP transmission? CLICK HERE

How can I get help? CLICK HERE





NAG1 722.6






SOUTHERN HOTROD LLC  warranties our performance transmissions against a “DEFECT IN OUR WORKMANSHIP” ONLY.

We will repair or replace our performance transmissions if SOUTHERN HOTROD LLC inspects the transmission and deems the failure to be a “DEFECT IN OUR WORKMANSHIP”. NO incidental or consequential costs or damages covered in our LIMITED WARRANTY  and no refunds will be given.  No removal, shipping or installation or other labor costs or allowances are warranted. Installation of these products may void the warranty coverage, if any, on your vehicle.  SOUTHERN HOTROD LLC shall not be responsible for damages or failures resulting from improper installation of the transmission or any other modifications occasioned by its installation, including modifications to transmission valvebody.  In order to make any warranty claim, original buyer must provide SOUTHERN HOTROD LLC with a copy of its invoice as proof of purchase.  THIS LIMITED WARRANTY IS NOT AN UNCONDITIONAL WARRANTY OF FAILURES OR HAZARDS. THE TERMS OF THIS WARRANTY BEGIN ON THE DATE THE PRODUCT IS DELIVERED TO THE ORIGINAL PURCHASER AND IS NON-TRANSFERRABLE TO ANY OTHER PARTY OR INDIVIDUAL. Any other express or implied warranties, including warranties of merchantability or fitness for a particular purpose are excluded from any warranty provided by SOUTHERN HOTROD LLC.