Is overfilled transmission a problem?

[Jim 450SL]

Recently bought 79 450SL. Found low trans fluid, just touching end of stick, so 2 lines or about 1 1/4 inches low. Assumed it needed 2 qts so I put in 1 1/2 qts Dexron III and checked again to top off. I had already overfilled it about 1 1/4 inches above full!!
Is this a problem I need to suck out or drain extra fluid, or is trans OK to run above full? Thanks for any advice!

[Stretch]

If you are absolutely sure that it is over filled then yes that is a problem.

The fluid level in Mercedes transmissions is a bit tricky to read though. You should check the transmission level with the engine running with warm (but not hot) fluid after you have given it time to settle down. This should be done on a level surface.

[Graham]

Originally Posted by Jim 450SL

Recently bought 79 450SL. Found low trans fluid, just touching end of stick, so 2 lines or about 1 1/4 inches low. Assumed it needed 2 qts so I put in 1 1/2 qts Dexron III and checked again to top off. I had already overfilled it about 1 1/4 inches above full!!
Is this a problem I need to suck out or drain extra fluid, or is trans OK to run above full? Thanks for any advice!

The fluid temperature has a large affect on the level. The owners manual explains how to measure level.

Definitely suck some fluid out if you have overfilled. I use my vacuum oil change unit, but in past used a turkey baster with a thin plastic tube attached. I would suggest doing this at low temperature (20c) and then check when fluid warms up (80C after a good drive)

[Jim 450SL]

Thanks for advice! Both say suck it out. Good idea for turkey baster. Such a dumb mistake!

[engatwork]

You are checking it when it is up to temperature, in park, idling arn't you?

[Stretch]

Originally Posted by Jim 450SL

Thanks for advice! Both say suck it out. Good idea for turkey baster. Such a dumb mistake!

You can also let it drain from the drain plug...


...and it is not a dumb mistake it is a very common one for those who are not in the know. After all everything is easy when you know how...

[Graham]

Originally Posted by Jim 450SL

Thanks for advice! Both say suck it out. Good idea for turkey baster. Such a dumb mistake!

It is hard to get exactly the right level, so don't feel bad. Even transmission shop gave me back my 107 with way too high a fluid level.

Last time (on my e320), what I did, was add fluid until level was slightly too high (at 20C mark) Then marked and wrapped some tape on the suction tube (using dip stick as a guide) so it would only just reach the required level. Then sucked excess out leaving correct level.

Probably more accurate than using the dipstick which often seems to show a different level on one side compared with other.

[dugald]

Originally Posted by Stretch

After all everything is easy when you know how...

And really easy when it's someone else who has to do it.