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#1
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Trouble getting accurate measurement of trans fluid
I decided to change my fluid and filter today...drained the torque converter and emptied the pan...changed gasket, let drip for almost two hours. Cleaned inside of pan with degreaser, let it sit in the sun to get bone-dry.
I knew I was a little low on fluid, but I only got slightly over 5 quarts out. Capacity is stated in the manual as 6.6 qts. I added 4, then started and shifted through the gears slowly, then put it back in park. I then added a another quart after checking the dipstick and not seeing a distinct line on the stick. So, therein lies the question: when i pull the dipstick out, it has trace amounts of fluid on it about 18" up - like it sort of rubbed on the side when I was pulling it out. No matter how clean it is when I put the dipstick in, I can't get a clean reading when I pull it back out. I've got just over 5 qts in now - and am afraid to over fill (many threads on this). Either a) I'm a dufus and don't know how to check a dipstick (aka I am a dipstick), or b) there is fluid getting on the stick from the sides of the tube that holds the stick. How can I get an accurate reading? (BTW, it shifts nice and smooth on synth ATF - no more flaring!)
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1984 300D: 275,000 miles (soon to be for sale) In search of my 1987 300D in anything but white. |
#2
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were you ever able to get an accurate reading? B/c i have the same issue you have, except all the time. I just guess
I also read a thread about checking when the car is cold, that the fluid should be no higher than the minimum line. Fill/check then. JBG
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JBG 1985 TD wagon, 228k running on grease since 3.07 AUSTIN, TEXAS |
#3
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If you can find the min and max lines on the dipstick you're not that much of a dufus IIRC only one side of the dipstick has those marks. MB has a spec for cold fluid level which varies by model. Most specs are between 10 and 15mm below the min mark so that's your target when topping after transmission service. The transmission should engage gears below that fluid level. Top up in very small increments once the transmission engages. When you get to that 10-15mm point and confirm there are no leaks from the work you just did, go for a 20 mile drive to get the fluid to operating temperature. I think operating temperature is 180*F but the rule of thumb there is if you can keep your fingers pinching fluid on the dipstick it's not hot enough. Only at operating temperature should you do the final top off to get the fluid level between the min and max marks.
Sixto 87 300D |
#4
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ATF level Check
1.Engine and Transmission Fluid at Operating Temperature.
[ATF expands as it warms.] 2.MUST have the Automobile on LEVEL...That's the AUTOMOBILE,even if you have to "Shim-It". [A nice 4Ft. Carpenter's Level "All Over" the surface you intend to park on helps!] 3.WIPE THE DIPSTICK WITH LEATHER RAG ONLY...or You'll be sorry! [The smallest,most infinitesimal fragment of lint from cloth or paper will clog the tiny,tiny passages and gear in the Transmission.] EDIT: I'm deleting everything below this in favor of the info SIXTO has noted above.
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'84 300SD sold 124.128 Last edited by compress ignite; 10-12-2008 at 06:03 PM. |
#5
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Quote:
I'll check the level tomorrow when I get up...maybe a cold reading will deliver a cleaner stick (that sounds filthy).
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1984 300D: 275,000 miles (soon to be for sale) In search of my 1987 300D in anything but white. |
#6
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I have found you have to give it half an hour or so to allow any fluid you have added to the tube to drain out and allow you to get an accurate reading.
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1979 240D- 316K miles - VGT Turbo, Intercooler, Stick Shift, Many Other Mods - Daily Driver 1982 300SD - 232K miles - Wife's Daily Driver 1986 560SL - Wife's red speed machine |
#7
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How about simply measuring the distance from the high mark on the dip stick to the top of the tube you insert the dip stick into. Then, with the fluid hot, use that measurement to insert clean, new plastic tubing that exact distance into the tube. The bottom of the tubing will now be at the desired high point of the fluid.
Now simply apply suction to suck out the excess trans. fluid and you will end up with the exact amount you are supposed to have. Assuming of course that the car is level and you indeed have too much in there (easy to do), and you have new, clean tubing. This seems to be a very logical way to easily get the right amount with little mess. Anyone see any hidden problems with this?
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'76 240D-Sold '78 240D-Sold '85 300 SD, 165K-Sold '88 300 TE, 165K-Sold '64 Porsche 356C Cabriolet- under restoration '86 560SL 124K Miles-Sold '94 320E Wagon, 74K Miles-128K Miles JUNKED '06 E350 Wagon, 84K Miles 07 SL550, 14K Miles |
#8
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That's brilliant, Ron, and it only took 5 years Seriously, it's elegantly simple.
Attach the extraction hose to a spare dipstick to make sure it gets to the desired level and doesn't curl. Sixto 87 300D |
#9
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Thanks for your kind words Sixto. Adding a stiffener is a good idea if you are using thin wall polyethylene tubing that will definitely go mushy in hot fluid. Best to use much more rigid Low Density Polyethylene tubing in the first place as it will hold up to hot fluid. I thought of using metal refrigeration tubing, but it will not easily slip into the tube. A vacuum brake bleeding rig would be a good tool to do the actual sucking of the excess fluid, or Harbor Freight or actually any aquarium store would sell a squeeze bulb "siphon pump" for about $6. I'll do a bit of research as to what will work best and post it so it can be easily found. No sense in reinventing the wheel every time. If anyone comes up with a product for sale using this technique, I demand a bottle of Cabernet as my commission.
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'76 240D-Sold '78 240D-Sold '85 300 SD, 165K-Sold '88 300 TE, 165K-Sold '64 Porsche 356C Cabriolet- under restoration '86 560SL 124K Miles-Sold '94 320E Wagon, 74K Miles-128K Miles JUNKED '06 E350 Wagon, 84K Miles 07 SL550, 14K Miles Last edited by Ron Johnstone; 02-20-2012 at 02:08 AM. |
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