alexanderfoti

Hi all

My 221 S65 AMG as an odd "quirk".

When driving around all is good. Full throttle acceleration, also good.

When slowing down at slow speeds (less than 30 mph), I get a tugging feeling from the gearbox/engine.

Almost like the engine is slightly slower then faster then slower than the road output of the gearbox and you end up with this non smooth slowing down.

I am not sure where to turn on this, whether its a torque converter issue or an ignition system issue.

I suppose I could turn the TQ off and drive it around and see if it still does it.

DaveW68

This sounds very familiar to symptoms the 5 speed auto in my S600 (same trans as yours) experienced a little over 2 years ago. It started out like yours, then happened intermittently, and they got worse in a hurry. Instead of having the dealer tear down the tranny to figure out the problem, my warranty company paid to have a factory rebuilt trans installed to the tune of around $7k. It happened when my car only had 28k miles. I hope yours can be resolved cheaper if you don't have warranty coverage.

alexanderfoti

Hm that is interesting.

Just from driving it, It feels like a torque converter issue.

I also have harsh torque converter engagement when cold, once warm the issue disappears though. I suspect the TC lockup solenoid is sticking in its bore.

DaveW68

It would probably be a good idea to get it to the dealer, have them hook it up to STAR, and see if it is throwing any codes. Although I've heard that some trans issues do not throw codes, so this could take some diagnosis time and possibly a trans tear down to figure out.

alexanderfoti

I have star, no codes on the gearbox at all, its quite happy in itself

alx

change tranny oil if over 50k miles on the oil, reset adaptations. use the opportunity to check tranny pan for funny stuff in it and burnt smell of oil

btw, all the v12 biturbos misfire and gurgle a bit on overrun... this is normal to an extent as long as it is not too violent

alexanderfoti

Already did the first. No oddities in the pan or on the magnet.

Oil was old but did not smell burnt.

Will reset adaptions

alexanderfoti

Update.

Drive with the TC lockup disabled. Problem goes away.

Reset adaptions and carried out manual TC adaption for all 3 torque ranges. So far seems ok. Will see what the box is like when its cold.

alexanderfoti

Back to same behaviour today again. Seems if I reset and carry out adaptions whilst the box is hot, all is OK. I think the odd Tc lockup behaviour when cold is throwing off the adaptions.