722.6 fluid color and 3rd-4th slight harsh shifting condition.
 

Hi there,

My car is a 97 SL600 w/722.6 , Transmission fluid looks like oil (i.e. honey colored). Is this the "early" fluid or just typical mercedes synthetic?

Before you think I've lost my mind, yes, I am checking the transmission. Had to break the red seal and use the special dipstick.

The car has developed a "slight" harsh shifting condition from 3rd to 4th It has about 54,000 mi and I was thinking fluid change may help. When I change the fluid and filter I plan on having a peek at the solenoid pressure regulator valve spring as I know these can be an issue with the early 722.6's. Anything else I should look at while I'm in there that could be causing this. the problem seems worse when its cold.

If none of this helps should I take it in for an adaptation tweak? How is the adaptation stored? can a transmission loose its adaptation changes if the battery is disconnected for a while?


Thanks for any help

--
CR
97 SL600

A fluid/filter change is always a good starting place.
Also check(disconnect & inspect) the electrical connector at the front of the bell-housing for fluid, it should be DRY.

The adaptation can be affected by the battery being disconnected
for a LONG duration.

There is a TSB on the early 722.6 with harsh 3-2 and 1-2 shifts indicating that a new ETC is required. Not sure about the R129 application, but you might want to look into that as well if you're suffering any other harsh shifts.

Don't forget that when setting the level of the fluid, the fluid temp must be 80C (not the coolant, the actual tranny fluid) for the level to be accurate. The 722.6 is sensitive to fluid level, so be careful on that one.

The only fluid approved for use in the 722.6 is the special synthetic that is directly from MB. I think it runs around $13/quart.

What color is the trans fluid supposed to be?

mine looks like oil, I have heard the approved fluid should be red. But looking thru the history I dont see a fluid change ever done.

????

Thanks for the reply's

--
CR

97 sl600

Do a search on 722.6 trans - I did a write-up on mine.

I have replaced the trans fluid on my 98 E320 at 80K miles. The fluid was dark brown with a thin layer of gunk on the bottom of the transmisison pan.

The new fluid is red in color - same color as regular Dexron trans fluid. My guess is that the fluid starts out as red, turns to honey color, and then turns to dark brown.

Since you have an early build of the 722.6 transmission, I would also recommend you install the magnet for the bottom of the transmission pan to aid in collecting metallic particles.

I also had hard shifts after disconnecting the battery. The computer will eventually relearn your driving habits and start to shift normall.