Mercedes 126 Repair – Transmission Service


The transmission in the Mercedes 126 is a pretty sturdy style, as a person would hope. In its day, it was a person of the best models offered, which led Porsche to use it in the legendary 928. But as with all other programs on these autos, we really should not let the status for longevity stop us from carrying out repeated providers.

As a typical rule of thumb, transmission fluid really should be transformed just about every thirty,000 miles. In contrast to contemporary autos, where the pattern is to do absent with services entry ports completely, these Mercedes transmissions let us to drain not just the pan but also the torque converter. In other phrases, we can remove practically the full fluid cost devoid of resorting to this sort of gimmicks as ability flushes.

Whilst engine oil really should be transformed incredibly hot, transmission fluid is best transformed when strictly warm to protect the mechanic from a pretty real possibility of scaling. The techniques are as follows:

  1. Drive the front of the motor vehicle on to ramps or support on jack stands.
  2. Make sure that the torque converter drain plug is obtainable. Unless you have been pretty blessed, you will ordinarily want to blip the engine on the starter to get the plug to arrive into view through the entry hole. It can be “walked” the relaxation of the way with a large, flat-head screwdriver. It may perhaps also be essential to remove the cross-member concerning the two front subframes (“dogbones”). The 6 retaining bolts have 17mm hex heads are are torqued to 45Nm.
  3. Loosen the transmission pan drain plug with a 5mm hex socket, then let the pan to drain into a suitable container. If achievable, acquire all the made use of fluid in a person container and then evaluate it this will support us dispense the appropriate quantity when we refill.
  4. When the pan has stopped draining, loosen the plug on the torque converter (exact same measurement as on the pan) and let the torque converter to drain out. There is substantially far more fluid listed here than in the pan.
  5. When the two major flows have ceased, loosen the 6 bolts retaining the pan (13mm heads) and very carefully remove the pan. Do not spill the remaining fluid all more than on your own! Resist the temptation to wipe the innards with a shop towel: we do not want any parts of lint in listed here.
  6. Get rid of and replace the transmission filter, retained by Phillips-head screws.
  7. Completely cleanse out the pan with a lint-free cloth and replace the rubber gasket, like a correct fit all the way all-around. Reinstall the pan, torquing the bolts little by little and evenly up to 10Nm. (The guide states 8Nm a minor far more is great. But make sure you do not go overboard: these pans can be warped and they&#39re not low cost.)
  8. Substitute both equally drain plugs, working with new copper crush seals. Manufacturing unit spec. is 14Nm, or about 10lbs / ft. Restricted with a 3/8 drive will work great. If you removed the cross-member, replace it, being careful not to cross-thread the bolts.
  9. (Optional) Crack open up the trans cooler traces at the radiator (17mm wrench) and drain the tiny amount of fluid from this spot. Substitute the traces if their affliction is doubtful they are not pricey. Retighten all connections.
  10. Employing a great-mesh filter, include four quarts of refreshing Dexron-Mercon transmission fluid (ATF) through the dipstick tube. If you can afford it, use artificial fluid: it assists hold temperatures down by reducing inside friction, and warmth is the variety a person enemy of computerized transmissions.
  11. Commence the engine and gradually include an additional three quarts.
  12. Back again the motor vehicle off the ramps, operate it through all the gears, pausing for a few of seconds concerning every equipment, then look at the fluid degree. You do not want to be more than the least mark at this stage. Transmission fluid expends pretty when incredibly hot the reference marks on the dipstick are calibrated for incredibly hot fluid. So it is okay to be half-an-inch or so under that mark whilst the fluid is chilly.
  13. Drive the motor vehicle for about 20 minutes (indeed, at minimum that substantially) to warm the fluid totally. Transmission fluid requires more time to warm up than the engine oil or coolant and needs the friction of real driving to get up to temperature. Verify the fluid again on degree ground. Make sure you do not go away any lint on the dipstick before replacing it in the tube. Any degree concerning the marks is great, but underneath no situation do we want to exceed the highest degree. If you want to include fluid, do so in pretty tiny increments and look at again.

If you are working with artificial fluid, you may perhaps observe that the shifts have become noticeably firmer. Alter, if needed, by adjusting the modulator valve on the driver&#39s aspect of the transmission. Change the minor essential counter-clockwise till the change high quality is to your liking. Bear in head that too substantially slip is lousy for the inside clutches.


Supply by Richard M Foster

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