driving a 4matic without the " 4 " ?

[milhan]

On my 1990 300E 4matic there is a lever under the hood to disable the front drive of the 4matic system in order to service. Could I drive for long periods with this lever pulled? Would it harm anything? It would seem to me a smart thing to do when driving in summer, then in winter engage this and drive in all wheel drive. It would save gas, and wear and tear on the front drive system. Does this make any sense, or am I an idiot? I had a 99 4matic with no such lever?

[OTTOBUN]

I know it's not a practice thought of highly on this DB but....

Mine is a 90 4matic also and I drove it in "test" (lever-up) for 2 years without incident...the only thing I noticed was the rear (limited slip) diff rumbled on tight, low speed turns (ie: like on 3-point turn, slow sharp turns), otherwise who knew? 99% of time the car is 2 wheeler anyways.

The test lever is not found on models after 90 or 91.

As far as reviving the 4wheel system after a long stint on 'test'...it might need to have a fault code reset, but it shouldnt. But if it does, disconnect a battery terminal 10 - 15 mins and it will erase the F/C; AND always keep an eye on the hydraulic oil resevoir (up forward on the drivers side, tall thin white plastic container with the word OEL on the black plastic dipper stick). If it needs topping up make sure you put the right stuff in it.

FYI it affects rear self-leveling system on TEwagons so....if yours is
a sedan no worries.

[michael cole]

the answer is yes.its no secret to anybody but mercedes benz that shutting down the system will extend the life of the components.however if you have a wagon this will also shut down the hyraulic rear suspension.with the motor running flip the switch to test and back again.this will generate a fault code in the 4matic computer effectively shutting it down.you can verify this by the 4 matic dash light always being lit.to reset when you are ready to resume operation simply remove battery power for 30 secs.this will reset the 4matic "brains"

[SRHARVEY]

We have a '93 300TE 4Matic. The 4Matic automatically engages everytime you start up the car, the light does not come on, at about 12mph it shuts down and the car has normal 2 rear wheel drive. While driving if you hit a slippery section of road, large rain puddle or icy spot the 4Matic will engage to control the traction. On totally slippery surfaces the 4Matic engages through three progressive degrees depending on traction.

If you shut the system down with the switch under the hood you not only lose the rear support system but you lose the traction control you might need on a summer rainy day. With the system engaged you are only using it for the short period of time each time you put the car in motion. I don't think that's a good trade-off. We leave ours engaged all the time. We have had very minor repairs to our 4Matic system in 260M miles using it full time.

srharvey
'82 SL 160M
'83 240D 240M
'93 300TE 4Matic 260M

[michael cole]

on a 93 4matic when the system is in test mode the hydraulic suspension is not affected.it is an electrical shutdown of the 4 matic unit