Transmission - No torque converter plug

[turboGT]

Hi,

I changed my transmission oil and filter last year. But today, I sent the car in again to change the transmission pan. They used the latest pan which is curved at the front. At the same time, they changed the oil and filter again.

The mechanic could not find the Torque converter plug although he turned the TC all the way.

So, he basically opened the cooler lines (at the front of the car) to drain additional old oil. The flow was very thin but it kept on flowing for 10 minutes. He used only 3L of oil to flush which I know is not enough.

Just to note that he did a full flush last year using much more litres of oil.

Only (almost) 6 litres of new oil was used to fill up the transmission. He assured me that he closed the drain plug as soon as the oil excess flow started to sputter to have the correct level.

Do you guys think that:
(i) it is strange that only (almost) 6 litres was used to refill the transmission?
(ii) Is it important to flush the transmission with "x??" litres of new oil at every oil change for cars which do not have TQ plug?

Thanks

 

[bob6600]

If it was done last year, why are you doing it again? Have you covered around 40k miles?

6 litres is probably about right (depending on model), assuming the TC was not drained fully

I have read it can take around 13 litres for vehicles with no TC plug, however around 10 litres should give you somewhere between 80-90% change

 

[Lenny63]

i know my CLK takes about 8.6 litres according to my MB parts dept including TC - in Ollie's DIY he uses approx 7

 

[markjay]

I don't know the answer to your question, but I would have thought that if the ATF was changed last year, it didn't really need changing again, so not really an issue is mixing new ATF with 'old' ATF, as the old is still good?

This could also explain the other issue... the correct way of emptying the ATF from a TC that has no drain plug is by disconnecting the pipes at the oil cooler, then running the engine allowing the transmission to pick up fresh fluid while collection the old one until clear ATF comes out. But this system won't work if the old ATF looks like new...

 

[turboGT]

I changed the transmission oil again because MB has never replaced the old pan with the updated one. what a shame

So, I guess that the oil which was previously in the transmission, cleaned the torque converter area, all the lines, etc?

So, maybe it would be useless to make full flush with 13 litres of oil again and the new oil did not get extremely contaminated?

 

[markjay]

...So, maybe it would be useless to make full flush with 13 litres of oil again and the new oil did not get extremely contaminated?

This is what I think. Unless you drove mega-miles since the last ATF change, it would be fine.