320cdi 7gtronic issue

Andreyy

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Oct 13, 2020
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Your Mercedes
w219
Hi. Can anyone tell me about the TC clutch in the 7gtronic gearbox. I have the issue(maybe..) .When I cruising about the 80km/h,and then start to brake gently(rpm start to drop in proportion with speed) and when the speed drops to the 30-40 km/h(rpm near the idle) the 2 gear now must be engagged..And after that,when i start to acelerate with the 25% throttle,rpm jumps to the 1700about(like the clutch slipping),and my problem is...when i realease the throttle, RPM DROPS TO THE IDLE...if I acelerate,and hold the throttle open for 2-3 seconds,then after that,when realease the throttle,rpm dont drops,it stays like in manual tranmsision,when you going on gear,and realese the throttle.. Now question..thats normal? I dont have much experience with automatic transmissions,but i think,that in this point of speed,the torque conventer is fully open? It slips? That issue sometimes repeat,sometimes no..but only in this low speed after gently braking... On any other conditions,when thorrtle pedal is realesed,rpm dont drops to the idle(like in manual trnamsission,when press the clutch pedal) rpm drops with the speed,car holds gear.. Maybe its TC issue and sometimes TC is stucks on fully open? And maybe anyone can tell me some about the torque conventers..how i can feel,when torque conventer fully locked-up,and what symptoms of fully open?Maybe my situation is fully open torque conventer symptom?
 

Botus

Senior Member
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Jul 29, 2014
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Your Mercedes
S500/2010/500
sounds like you are overthinking it

when was the trans fluid changed? needs doing every 37k miles. nasty boxes that are fragile and dirty fluid wears them out.
it causes wear and or electrical issues with all the metal running round
also may be low on level which won't help
as the right way to do a change is to double flush (as so many areas can't be reached and litres of fluid stay in places), even if you need to swap stuff inside solenoids, TC or electro plate having it almost clean from the first change will help...
 

rifiki

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Dec 29, 2015
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Location
Worksop
Your Mercedes
CLK W209 W121190B
The 7 speed on my CLK does much the same thing, just let it get on with it.
 

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