4-matic questions - PeachParts Mercedes-Benz Forum

Freestyler · #1 09-11-2002, 05:46 AM

Hi everybody.

A couple of months ago i purchased my very first MB. -A '86 300E modified to appear as a '95 model.

I have been looking for a good MB forum and it seems like i've finally found one!
As a MB newbie you'll have to forgive my lack of knowledge about this car, but i do know how to use the search function. -Which btw. hasn't helped me on the upcoming questions..

When i lift the foot off of the gas pedal during driving, i would presume the 4-matic's clutch would disengage and engine rpm's would drop to idle while the car coasts along. It doesn't! It feels just like a manual tranny where engine rpm's follow wheel rotation during decceleration. Is that the way it's supposed to work?

And when coasting to a stop, the 4-matic changes to a lower gear -with an accordingly slight increase of rpm's, just when the car comes to a stop. -Which is actually pretty hazardous because i don't apply much brake power when easing the car to a complete stop behind the car in front of me (at a red light fx.) And when the 4-matic changes gear, the car leaps 3 ft. forward..!

Is it supposed to work like that?

In short.. Do i need a rebuild of my 4-matic or is this some sort of adjustment issue?

Thanks in advance
Freestyler

mbdoc · #2 09-11-2002, 08:23 AM

($)4-matic is only a traction system. What you are describing is an automatic transmission problem OR design "flaw". The 4-matic system works upto 12 MPH every time that you start from a standstill. Other than than that it will work IF & when wheel slippage is too high below 25 MPH.
Sounds like the transmission modulator is out of adjustment OR defective. Have you had the ATF in the transmission & in the TRANSFER case changed? They have their own fluid capacities.

Freestyler · #3 09-11-2002, 09:14 AM

Oh.. I thought '4-matic' was the term used for the entire gearbox. Guess not.

No. I haven't changed ATF, but will do so. What's the recommended intervals for that btw.?
And what's with the "transmission AND transfer case"? There are two different oil reservoirs?

How do i check and adjust the tranny modulator?

Bare with me.. I've never had my hands on a MB before.

Freestyler

mbdoc · #4 09-11-2002, 05:23 PM

The 4-matic part(s) consist of transfer case, locking rear differential, & the front differential. The transfer case is a bolt-on that has it's own drain & fill plugs. It does use ATF.
OF course there is a computer & hydraulic componets as well.

The trans modulator has a rubber cap that can be removed & then the key underneath can be pulled slightly out & turned counter-clockwise to soften the shift.

Freestyler · #5 09-12-2002, 12:37 AM

Thanks M.B.DOC
I'll give it a try in the upcoming weekend.

Freestyler

pentoman · #6 09-12-2002, 04:31 PM

Nobody mentioned it... - You do realise, your car has 4-wheel-drive, yes?

Our 300E 4matic has plenty of miles, never with any problems, except needed tranny rebuild at 175,000 or so.

Your problem sounds nothing like the usual problems leading up to a big $$$ tranny fix though, so don't worry.

Have you driven many automatics before? I always used to think they disengaged when you let off the throttle pedal too.. right until I first drove one about age 14. If they did don't you think it would be pretty horrible? No engine braking either!

later!

Freestyler · #7 09-13-2002, 09:57 AM

My car has 4-wheel drive?

[edit] Oh man.. I just did some research into the world of '4-matic'. And as all of you allready know and i just didn't had a clue of, it turns out to be a 4-wheel drive system.. -Which is not present on my MB.
My mistake originates in my firm belief in that '4-matic' was the name of the 4 gear auto tranny. Do i feel stupid or what.. -Though a little wiser now.[/edit]

I have only driven an old Opel Admiral and a new Dodge Ram with automatic before my own Benz. Both of them dropped rpm's to idle when you let off the throttle pedal. -No engine braking at all, unless you put the gear lever in 3'rd or 2'nd gear.

Freestyler

pentoman · #8 09-13-2002, 03:11 PM

Don't worry, first time I ever saw a 4-matic I thought the same thing. An almost new W124, I used to ride to school in the third row seats in it.
Now, 200,000mls and 12 years later, we own the car!
But that was before we had any MBs, I'm somewhat more clued-up (and old enough to drive) now..

later!