I recently purchased a 1993 300TE 4matic with 136000 miles. The transfer case was replaced last Apr. 04. And I have recently replaced the brakes and rotors and stabilizer bar. Except for some hard shifting by the transmission the car seems to perform very nicely. However, the 4wheel engaged light in the speedometer comes on consistently at 75 MPH and stays on above this speed, then goes out below this speed. It does not matter if I am going straight or in a turn, and the roads are dry and clear this time of year. The light will go out at speeds above 85 MPH.

Does anyone have any suggestions about what component to look at to correct this problem. Am I doing harm to the 4 matic system by driving at these speeds with the light on.

Please help if you can.

dennisol

Hi, I think I would look at the speed sensors first. Maybe they just need a cleanout. They can't be too bad if the 4-Matic engaged light only comes on at those speeds. I had to change both front sensors as the light came on almost constantly and gave me problems with the ABS as well. Now all is ok except for erratic steering sensor input when turning.
I don't think it will do any harm to the 4-Matic system as at that speed you should only be in "Stage 1" ie. 35% front / 65% rear and would in fact probably have enhanced road holding as well. You didn't mention if you could feel any unusual forces through the steering wheel when this happens.
Another thing that could cause this would be the rolling diameter of the tires. If you have different tires back/front it is possible that they behave differently at high speeds. Just a thought....
Tom

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'90 300TE 4-Matic

Thanks for the reply. I don't feel any difference in the steering when the light comes on versus when it is off. The tires are the same size all around. I put 30 lbs of pressure in the front and 36 in back.
A mechanic reported that were no error codes reported by the transfer drive system.
Still searching for answers, but I think the speed sensors may be the place to start.