Welwynnick

Hi All,

My 2004 V12TT is up to 148k miles, and I've decided to change the trans fluid. The car has a full mercedes dealer service history, but I can't find any evidence of whether the trans fluid have been changed.

I've read everything I can about this, and I'm pretty comfortable with it, but there's one question I can't answer:

Is it possible to drain the torque convertor?

I've read that 722.6 trannys up to 1999 had TC drains, but not after that. I also read that drains were re-introduced later, once MB realised that sealed-for-life wasn't realistic. So does anyone know which it is - does the TC have a drain, or will I only be able to drain the pan? :-(

Thanks in advance,

Nick

biker349

hi, just had this done at the dealer. there is no converter drain plug. the drain and fill along with filter replacement only required 4 quarts of fluid. you can get a flush, but you'll probably need like 15-20 quarts. i'm going to wait a few hunderd miles and drain and refill with 4 more quarts. this will replace most of the old fluid, since the tranny holds 8 quarts

shardul

iTrader: (1)

You have to disconnect the feed and return lines going to the transmission cooler to drain all the fluid from the system. Some people don't recommend draining the tc.

PelicanParts.com

To avoid issues.
I suggest having it flushed by MB, or a qualified after-market shop.



roy@pelicanparts.com

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Welwynnick

Thanks for the input guys. I spoke to a highly-regarded independent, who said similar things. He also said some thing else very interesting. They found that the trans oil cooler pipe within the water rad had a tendency to leak, so small amounts of water got into the trans fluid.

So they developed a mod to add a separate trans air/oil cooler in front of the main rads. They've been doing this for years (along with regular fluid changes) and lots of problems have gone away. Anyone else heard of that?

Nick

biker349

hi, what is the cost of that mod and where is this indie located?

Welwynnick

The mod was about 300, but they're here in the UK. It sounded pretty straightforward.

Nick

shardul

iTrader: (1)

yes transmission fluid mixing with the coolant is a common problem. MB even sells a glycol contamination testing kit.
Simple fix is cap of tran fitting on the radiator and connect the transmission lines to a transmission cooler and mount it in front of the radiator.

Dynodaddy

No drain plug but you need to drain all of the fluid, drop the pan, change the filter and clean all of the sedement out of the pan and off the valve body. I did this at 100K or so and it was absolutly disgusting. There is only so much a flush will take care of.

Welwynnick

Yup - in the end I did all of that; twice. The oil was brown rather than red, and the pan was dirty, but not ridiculous. Cleaning the magnet was time-consuming, but it felt like it was doing good.