change tranny fluid on a 97 e420?
 

I did a search already but could not find much info on this topic. My dad has a 97 e420 that is "due" for a tranny fluid change. At least that's what one source says. There are conflicting opinions on this subject. He read one place that the fluid should be changed every 60k miles, and somewhere else said that the tranny system is "self-sufficient" and the fluid never needs to be replaced. I did not believe this "self sufficient" stuff at first, but after he told me that you actually have to purposely break a part and replace it just to change the fluid, I'm not so sure. Anybody know what the truth is on this subject?

p.s. He already bought the oem fluid and replacement for the part that needs to be broken.

YES, YES!!

Don't wait, replacement transmissions run $4000 on those cars!
Fluid & filter change should run $225, you do the math.

I remember in a previous post that tranny fluid intervals should be done at approx. 100K. I believe it was one of the frequently visiting techs here that mentioned that, maybe Gilly, Don't remember...

These are pretty sophisticated transmissions and rather durable. I've heard of people with other E300's on this board with 200, 300K and no mention of tranny replacement. Not saying that they are bulletproof though.

Just my $0.02

Lifetime trans fluid is more marketing hype than reality, and is aimed at people looking to buy a "low maintenance" vehicle. These people don't want to hear about all the trips to the dealer neded to maintain a vehicle. They just want to buy a car and not worry about it.

Trans fluid DOES wear out. If you do it yourself, fluid and filter can be changed for under $40. Very cheap compared with the cost of trans replacement.

Beware, the ONLY approved fluid for the 722.6 transmission is the special sythetic from MB. Runs about $13/quart and it should take in the neighborhood of 8 quarts or so for the sump and torque converter.

There is a drain plug on the torque converter on model year 1997, so I would drain that too.

If you do your search with the terms "722.6" and "Fluid" you'll find lots of reading.

There is no way to do a 722.6 fluid/filter for $40. You MUST use the MB synthetic fluid, and it's price varies from $10 to $20US per litre. Even at the best price, you'll need $80 in fluid before buying the filter.

I have the dealer do this job. Though it's not difficult, here's why:

1. There is no dipstick. With such long intervals (about 60K-miles seems "normal.") I see no reason to buy one. I don't check the tranny fluid on an ongoing basis, and changes come every 4-5 years.

2. The fluid level must be set precisely. This tranny is very sensitive to fluid level. The fluid should be at 80C for the level to be set. Your dealer can do this.

3. It's not labour intensive. My dealer only charges an hour to do the job. For $80 in labour charges every 4-5 years, I can handle the cost. $80 seems cheap to me to ensure the job is done right. The 722.6 is a tough tranny, but who wants to muck up a $5000 piece of gear? Not me.

Have the dealer also check for the updated ETC (there is a TSB on this) and have them install the magnet in the pan when they button it back up.