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1999 Mercedes ML430
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4 Posts
Discussion Starter #1 (Edited)
Hello all,

This is my first post here. I read practically every post on this forum about the 722.6 (fluid types, how to add, over/underfilling etc...). I will give my back story and then my question:

Our 99 ML430 was running perfectly until one day it sprang a leak at the trans park lockout linkage bellows. Drained the tranny by pan drop (about 6.5 L drained out). Changed out the part. Cleaned out the pan. New gasket, new filter. Put it back together. Ambient temp in garage, 9 Celsius. Added 5 L to start (MB Fluid Spec 236.14). Started car, allowed to idle until tranny was at 25C (using IR thermometer at trans pan). Inserted dipstick tool until it bottomed out. Marked on dipstick tool where bottom out was so as not to push too hard and give a false reading. Filled trans until 25C mark on dipstick was in upper range (at about 6.5 L now). Drove vehicle 40 miles. Re checked trans temp at pan, 72C. Drove more, came back, same result, 72C. Topped trans at that point to lowest mark on 80C range.

My question. With the ambient outside temp being between 5 & 9C, how far off could the IR reading at the pan be? Is it possible that at 72C I am actually closer to 80C fluid temp?

The reason for this question, the first time I took the car out after making sure the fluid was set at 25C, the car shifted into reverse with no problems, but did not fully engage into drive until I revved the engine up to about 1500rpm. Once the internal pressure increased, the trans suddenly engaged into first gear, rather harshly. After that initial shift, there were no more problems. I am concerned that when I took the initial reading off the pan at 25C, the temp was actually higher and I had a false reading, resulting in a low fluid level.

I have yet to try again, as I topped the fluid off about 15 minutes ago, and the vehicle will not cool down fully until the morning.

Thanks,

Damon
 

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Dallas, Texas
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7,767 Posts
Every time I approach my cat with thermometer in my hand he has this look. It's really hard to describe.

Don't let your ML develop that look.

2mm up or down on the dipstick does not make any difference. Fluid level difference at 72C and 80C is not measurable. Not with dipstick anyway.
 

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Registered
1999 Mercedes ML430
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4 Posts
Discussion Starter #3
That being said, am I better off increasing the fluid level to the mid way point of the 80c section on the dipstick?
 

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2000 ML320
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355 Posts
Yes that is the right idea to "sneak up" on the correct level i.e. add fluid slowly. Overfill and risk blowing out seals (bad and to be avoided)

My ML thermostat maintains coolant temp at 80 deg C; point being that if driven for an an extended period then the trans fluid is also be @ 80 deg C.

Make your measurements on level ground with the engine running using the correct fluid and dipstick tool. I agree with Witek +/- 2mm from the 80 deg C mark is "close enough for government work" as my Dad used to say
 

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2001 ML430 Sport bought in very nice shape despite 156K miles in August 2010
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540 Posts
I need to stab my mind's eye. Can't read this thread without seeing Witek's cat giving him the stink-eye.
 

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2001 ML430
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468 Posts
After refilling your tranny, you must hold the brake on and slowly shift it through the gears, then leave it in N for testing. Fluid does not flow well in P. You probably had a servo that was empty of fluid until you revved it.

I start it up, pull it into N for a few minutes, then R for 10-15 seconds, then D, then down shift slowly down through all the gears and back up, then leave it into N to test the level.
 

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1999 Mercedes ML430
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4 Posts
Discussion Starter #7
Guys,

Thanks for the help. I warmed it up to 75 degrees at the pan, Checked it in neutral, and brought the fluid level up just a little bit more.. Viola! It works great now.. Shifts like never before (good crisp, yet no hard shifts).

I appreciate your input!

Damon
 

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ML 270CDI 2002, BMW K1300S, VW POLO 1.9TDI
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515 Posts
After refilling your tranny, you must hold the brake on and slowly shift it through the gears, then leave it in N for testing. Fluid does not flow well in P. You probably had a servo that was empty of fluid until you revved it.

I start it up, pull it into N for a few minutes, then R for 10-15 seconds, then D, then down shift slowly down through all the gears and back up, then leave it into N to test the level.
Never check the level in 'N'. The official MB instructions are to always check the atf level in 'P' (engine at idle and the car on level ground and at normal running temperature). Apart from operational reasons, i wouldnt want to be doing anything under the bonnet of a powerful vehicle with the engine running without the transmission in its locked position .. ie.. in PARK
 
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