Adding more power output to an engine directly affects transmission reliability!

The 722.6-W5A580 transmission is rated to 580nm (427ftlbs but can handle a lot more to a point) there is torque limiters in tcu control to a certain extent per gear and can be exceeded easily by the m113k engine and other vehicles like srt8 that use these 5g transmission. These transmissions don’t blow up right away, but eventually, fail and need to be overhauled or replaced. Experience on the drag strip by hundreds of racers gives us this info. The torque rating on most gearboxes assumes that you will get a long lifespan out of that box with the engine in stock form. 2 different things can happen as you exceed that rating. More wear and tear (shorter lifespan) or catastrophic failure. Kaboom baby. There is only one way to find out. Test until failure, like what you see on most M113k cars that are modded to the extreme on stock 15+-year-old transmissions that hardly ever see transmission services, and they are thrashed on daily. Age of clutch piston seals, clutches, old atf and add in 200+ftlbs more torque they become a ticking time bomb, and no Tcu Tune or Modded Valve Body is going to help.

Have a heavily modified engine, the best bet is to rebuild the transmission with quality high-performance clutches set at factory clearances, quality seals, throw out brown-top solenoids, and install blue-tops and TCU tune. For major engine mods swap in 150% valve body along with TCU tune for best performance. These transmissions should hold up to 850 ft-lbs without a billet input shaft setup or adding extra clutches with just more torque reduction during shifts.

Prevent Transmission Overheating & Avoid Failure

Heat is the number one cause of premature transmission failures. Not manufacturer errors, or even defective parts. It accounts for approximately 90% of all automatic transmission failures.

Excessive transmission heat is responsible for the start of many transmission problems including; ruptured/damaged seals, cracked gears, slipping transmission clutches, failed bearings, inoperable solenoids, and delayed clutch engagement. You name the part, and too much heat can cause it to break.

This silent killer has claimed the service life of countless transmissions, and it could be wreaking havoc on your vehicle every time you put it in gear. An overheated transmission can often go unnoticed until it’s too late and something breaks.

The most common causes of overheating include solenoid problems, fluid leaks, low fluid levels, and burnt/old fluid. Other heat-generating factors are if you live in a hot climate, often drive in stop-and-go traffic, and/or tow heavy loads with your vehicle.

Fluid Life Expectancy vs Temperature

Over time, heat breaks down the organic compounds inside the fluid, causing it to take on a darker red, then brown, then black color. It also becomes thinner, which significantly reduces the amount of heat that it’s able to carry away from the moving parts.

If your transmission isn’t serviced (new fluid + filter) every 20,000 to 30,000 miles or once every 12-18 months (12-15k miles if the car is driven hard), the fluid will become ineffective, and the normal operating temperature will increase.

The ideal operating temperature of transmission fluid is 175 degrees. Overheating occurs after the temperature surpasses 200 degrees, and the failure rate doubles for every additional 20-degree increase after that.

So if you drive the vehicle with the fluid temperature at 240 degrees, your transmission will develop significant problems and fail 4 times sooner than it would have otherwise. Fresh, clean fluid, on the other hand, will make it run cooler, shift better, and last longer.

722.6 5G (Nag 1) Transmission Fluid

We use Valvoline Max Life multi-car fluid in all our 722.6 rebuilds and services. Says Mercedes Nag 1 on the back of the bottle so make sure you get the correct version.  The low cost of this fluid allows for more transmission services and longer transmission life. Can be found at your local Walmart.