Most Mercedes models from the 2000s through early 2010s use the 722.9 7G Tronic transmission. Most models have a torque converter, while some AMG variants have the MCT wet clutch system instead. Regardless of which type, the process of flushing the fluid is very similar. This is not the easiest DIY as it requires multiple special tools, as the transmission must be filled through the drain plug hole. In addition, the only way to obtain the proper level is to first fill the transmission, and then let fluid drip out of the pan until the fluid reaches 45 degrees C. It is recommended you complete this service every 40k miles.

FCP Euro Writeup (Should help you determine if you need to upgrade, and what fluid to use. Fluids are NOT backwards compatible so make sure you are using the correct version for your vehicle): https://blog.fcpeuro.com/mercedes-7-speed-transmission-service-walkthrough-722.9-transmissions

MOTIV Power Filler: https://www.amazon.com/Motive-Products-PowerfillPro-Extractor-Gallon/dp/B0119DHX7O/ref=pd_lpo_263_t_1/138-5273402-5490722?_encoding=UTF8&pd_rd_i=B0119DHX7O&pd_rd_r=63457253-c19c-495f-bf9e-1e31edc89eb9&pd_rd_w=Q5HL5&pd_rd_wg=HHFsT&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=JB7QBA9SJHYEXVXXG45E&psc=1&refRID=JB7QBA9SJHYEXVXXG45E

Fill Adapter: https://www.amazon.com/gp/product/B07JBHHWK8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

ATF Return Line O-rings (You need 2): https://www.fcpeuro.com/products/mercedes-auto-trans-oil-cooler-hose-o-ring-genuine-mercedes-mer-0199975845

Trans Pan Upgrade + Service Kit for Earlier Model 722.9s: https://www.fcpeuro.com/products/mercedes-722-9-transmission-pan-upgrade-kit-pentosin-001989680310

Trans Service Kit For Earlier Model 722.9s (ATF134 Fluid): https://www.fcpeuro.com/products/mercedes-722-9-transmission-service-kit-722-9-oem-7229erlysk1

Trans Service Kit for Later Model 722.9s (ATF134 FE Fluid):
https://www.fcpeuro.com/products/mercedes-722-9-transmission-service-kit-pentosin-7229late

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