I have a 99 ML320 with 98000 miles. Mi MB dealer says that the transmission is sealed and requires NO service under normal wear. My local service shop says to service and replace fluid at about 60000 miles. Which is it? I am not having any real issues with performance.

Hello,

I changed the fluid on my ML because the pan gasket was leaking. Otherwise you really don't have to change it. If you search this board you'll find this topic beaten to death. Several of the MB techs on this board feel that if you're going to have problems with the transmission the fluid change isn't going to have any bearing.

Your dealer is stating Mercedes policy, your independent shop has nothing to loose changing your fluid. Personally I tend to agree that if you don't have a problem leave the transmission sealed.

Matthew

MB says the transmission fluid is “Life Time” but yet they what you to install a magnet to collector any metal that may be in the fluid. The early year’s 722.6 transmissions also had a metal contamination problem with the solenoids and RPM sensors, that’s why the new updated conductor plate and solenoids protective covers were introduced.

The fact is metal particles and clutch material are contaminating the fluid every moment the car is running. A restricted filter will affect the pumps capability in producing working pressure, thereby minimizing the clamping force of the bands and clutches.

To extend the life of the transmission I recommend a transmission service to my customer’s every 35000 miles.

There isn't any trans fluid & OR filter designed to last 200k, 300k, .... 500k miles!

If you wait 90K to service the trans, small metal particlesl in the fluid will cause damage to the bearings & other rotating parts. WE have replaced 100's of those transmissions at 75K-100K miles that could have gone 200K miles if they were serviced at 50K-60K!

A service will cost $200-$250 but a replacement trans will cost $3500-5000, take your pick!

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Preventative maintenance never hurts. If you use the search function, you will find the issue of replacing the fluid in the 722.6 tranny has been discussed a lot of times. Service with only the approved MB fluid and make sure whoever changes the fluid is up to speed on making sure the fluid level is correct in the tranny.

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Ali Al-Chalabi

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