The 722.6 / NAG1 is a relatively robust transmission, and rarely anyone has any major issues with them other then the mentioned conductor plate connector seal, and the odd conductor plate contact issue. Please let us know the outcome of the diagnosis as i am curious what happened. If it did infact run low and fluid, one of the fail safes is to drop out of gear to prevent clutch pack wear and burning as it is not able to sustain proper internal pressures. The fact that you kept on driving on it could of most likely toasted the transmission. Which is not ideal, but.. im assuimg C32's and SLK 32's were sold in Australia? so a used 722.6 from those should be applicable.. I tried to find the proper 722.6xx designation, but i cant find it listed.


Edit.. looks like 722.641 is the model you will need to replace the trans in the Xfire tied to the M112.961 engine, if unfortunately you have to go down that route.


One thing that i saw happen that caused erratic transmission behavior was bad contacting inside the shiftier assembly. probably due to a split drink. A quick disassembly, and clean resolved the issue of intermittent limp mode

Most of the stuff i work on for fun are the 722.3 trans found in the older classic Benz, but i have done alot of homework on the 722.6 as im planning to do a M113K+722.643 swap into my 560SEL when i have time, with alot of built up internals.