I know, I know... but please help! (Trans fluid)
 

I know that the manual says that the engine should be running, the temp at 80C and parked on level ground....

I just had the trans fluid and filter changed but the shop over filled it slightly... (2 mm above max mark)

I already drained some fluid out... but I want to make sure I am doing this correctly...

When I check the fluid, the car should be on level ground, be idling, and the temp should be at 80C for the readings to be accurate (says the manual)...

I took my car around the block for 10 minutes... temp reads 80C...
I drive into the garage and put it in P gear... pop the hood and I wait for 2 minutes (exactly)... then I remove the dipstick, clean with lintfree cloth and reinsert completely, but do not lock it in.... then I remove and check...

I am currently reading way below the min mark, the level seems to be about 3 mm about the hook area?

When I stop the engine and then check after maybe 5 minutes, the fluid level is way above the max mark....

I am sooooo confused... :confused: :confused:

Should I add fluid or am I doing this all wrong?

The temp should be EXACTLY 80C, not "above 80C". You have NO WAY to measure this correctly. IMHO MB shouldn't even sell the dipsticks. It is worthless without knowing the temperature of the oil. You need to take the car to a shop (note I did NOT say dealer) that has SDS to read out the temp of the fluid.

Gilly

How do you know what the temp of the transmission is? I assume this is on your 300E? I have monitored my tranny temp with an infrared thermometer on the pan to get a reasonably close temp reading. It takes a lot to warm that tranny up to 80C.

I see.... I guess i will have to just pick up one of those infrared things...

that should help me get it right!

Thanks people!

The level must be checked/read WITH THE ENGINE RUNNING and the lever in 'P'.

AFAIK my independent shop doesn't have any sophisticated equipment to measure the transmission fluid temperature when confirming that the fluid level is OK. Since they work on MB's for a living they know how much fluid to add for the initial fill. Next the tech drives the car for a few miles then checks the level with the engine running and adds another half-pint or so, as required, for the proper level.

Good catch, John! That didn't strike me until you posted it. This is an indicator of absolutely nothing!

This temp/level relationship is alot more important than it is being credited for. A small variation can really degrade the shift quality on a 722.6. Need to use the proper equipment to obtain the trans fluid temp reading.

Gilly

Which car is this that you are checking the fluid level on? Is this the 300E?

Hello,

Yes this car is a 1989 300E...

I just want to know if the indicator should read between the min and max marks...

I check it after I go for a drive...
the engine temp reads 80C
the car is parked on level ground
the engine running in park

I am reluctant to buy an infra red device just to use one time....

Help me please!!! How do you all check it without the temp reading devices?

Just because the ENGINE temp is 80 C does not mean the TRANSMISSION FLUID is 80 deg.
As stated by our resident Guru ( Gilly ), the only way to read the temp. & fluid level correctly is with the proper tool.
I'm sure it would not cost you a fortune to have it checked at an M-B dealer. ;)

okay, I wil just have to take it to a place with the right equipment... thanks

Help me understand why you would need a special tool to check tranny fluid on an '89 300E ?

MB maint manual - 1981-1993 has a clear procedure for doing this. No mention is made about using a special tool.

Manny pointed out something worth noting. 80C eng. temp. means nothing.

You can do a cold system check for starters to make sure you are close.
On a cold motor, you would start it up, shift it thru the gears, put it in park, pull stick, clean, reinsert, pull and check. If fuild level is no lower than 10mm below low mark, you're OK.

Now go drive it for about 20 miles. Return and do same check as above, only this time level should be on hot mark.

Hey, that's a pretty good procedure....

I am just nervous about the fluid level being off, I don't want to trash me trans.....

the thing is that the manual says that the dipstick levels only apply if the trans temp is 80c

you are all rigt about the engine temp not having to do anything with the trans temp, I am just stupid, slow, or both! :D

"When I stop the engine and then check after maybe 5 minutes, the fluid level is way above the max mark....

I am sooooo confused... "

Does this sentence mean that after 5 minutes or shut down, you start the
engine and then check the level? If yes, then you need to move the shift lever through the gears before checking the level. The tricky part is measuring the level just after filling with new fluid. The fluid is on the walls
of the tube. Takes a while before you can get an accurate fluid line on the
stick.

My experience on 3 different 300E's is simply to adjust the level with cold fluid to about 10mm below the minimum mark. I know from experience that
after running down the highway for an hour , the tranny fluid is heated up. Checking the level shows it to be between min and max. I've never had a transmission problem. Current '92 300E is at 219K miles with
transmission fluid and filter changes every 30K.

Common sense tells you there is some tolerance built into the fill level. Otherwise, there would not be a min and max mark on the dipstick.
I seriously doubt that shops are measuring temperature to get the fluid level
just right.

Steve White

Great detective work. ;)
I thought he was talking about his 1999 car. :o