SL55/63/65/R230 AMG: SL55 722.6 Full Flush
Just to document for future use, I did a full system service and flush on my 03 yesterday.
Supplies:
(I get this kit from FCP Euro: https://www.fcpeuro.com/products/spr...febi-558600141)
Trans filter
Electrical bushing
15qts trans fluid (I used valvoline max life atf. I’ve had great long term success with it in my other 722.6)
Trans pan gasket
12-24” of 5/8” hose
Normal trans service tools: torx, allen, and sockets.
19mm open end wrench.
Normal procedure for the drain and filter swap. Plenty of YouTube videos on that.
Next, you’ll want to disconnect the transmission cooler line at the radiator. It will be the lowest fitting on the radiator of the two trans cooler lines. It will take a 19mm open end wrench to remove the fitting. see picture below, it’s right above the lower radiator hose.
Now slide the 5/8” hose over the threads on the radiator, you can twist it on to help it to seal.
Point the hose into a suitable container and have someone crank up the car and run for 20-30 seconds at a time. Refill Trans after each interval.
After about 12qts it will start to be fresh fluid coming out of the hose. This will flush the torque converter, cooler, and most of the lines.
Reinstall the cooler line on the radiator and check fill level.
All done!
Last edited by 6_Myles; Feb 27, 2022 at 03:30 PM.
My question/comment - did you ever do the torque converter method and was this one easier?
Secondly, on the radiator connection is there an O ring or seal that should be changed out while it is apart?
No, the radiator cooling line connection is a metal compression fitting. No o-rings or seals I noticed.






