No 4Matic
 

Hi. New here and hope this is the correct place to post my question. I am looking at a 300TE 4Matic which I would like to buy. The problem is the seller tells me that the 4 wheel drive system was no longer working, his local Mercedes dealer diagosed the exchange box as having an oil leak and the car had shut down the system. Is this correct and is it easily repairable? He has been using the car for months as it is with no problem.

Thanks in anticipation.

Roger

Sorry to torkydzl For posting in his thread by mistake.

Hi potential 4matic owner.
I was recently in your position and took the plunge and bought a not working 4matic on the basis that being a Mercedes product it would be fixable and reliable. I may have been wrong. The 4matic is fixable but any forum search will show that there are many and recurring problems with early 4matic cars. Mercedes later changed the design significantly on later models and these appear relaible and more what we expect from Mercedes.
The early 4matic system is clever but a little complex and I have not found anyone anywhere that truly understands them and is experienced in fixing them (if anyone doubts this please send me the link to them!). While I believe I understand how mine has failed and I believe I can fix it, it is costly and will not increase the value of the car anyway.
I have converted the car to 2wheel drive and may revisit the 4matic if or when I can get some good advice.
Converting to 2WD is fairly easy, if anyone wants to know how, I am happy to give details....

Regards,

Farmbenz

Thank you for your reply. The 300TE is a 1989 so I guess this is early? I have read that conversion involves swapping out the gearbox and drive shaft for the standard 300TE one. Is your way different? A little academic really as I would want the 4WD.

Roger

I'm not too sure when US got various models but I think the US1989 model would be the first series.
Essentially the 2WD conversion is simple. I used a second hand 300E transmission because mine was badly rebuilt and wrecked but you could use the original with the rear case left on (this is also the front part of the transfer box case). The 4matic gearbox crossmember is used with the 2WD mount. Hydraulics can be reliably plugged to be leak free but it is a bit of a pain to bleed them. Theoretically the rear diff will still lock as it should but I have not tested this nor needed it yet.

I want the 4WD too but at $3500AUD for the parts to repair the 4matic plus my time, it is a difficult problem.
Take note that there have been no replies for the request for someone who really understands and has experience repairing 4matics.
Unless you can fund a dealer doing the work I would go for a later model 4matic (Im sorry but I don't know when they got better).
Regards,
Farmbenz

Depends on what you mean by "better". Personally I prefer the older style 4-matic myself. The new system has all open differentials and brakes any wheel that reads faster than the others. The older system has a locking case and diff. If there is wheel slip it LOCKs the case and diff. It's not as smooth and seamless but I really like the posistive engagement it gives. Granted it is prone to more failures but that is the price of feeling that case lock and knowing that you have the grip.

To answer the originals posters question, the transfer case does have a tendency to leak hydraulic fluid internally. The typical repair is to replace the T-case with the updated unit which has less tendency to leak internally.

Thanks for that. I rebuild old Land Rovers as a hobby so swapping out a Tcase should be straight forward (famous last words) Is the leak due to gasket failure or distortion of the case normally? Any Special tools needed for the job?

Rebuilding the case yourself is pretty much out of the question. There are two problems with this. First is that getting the piston back together without the special tools is virtually impossible. The other is that the case itself wears out where the seal rides. When they are rebuilt the case is sleeved.
The best answer for this system is to just maintain it with the leak. Simply keep the hydraulic fluid topped off and the system will continue to work as designed with the leak. Then all you have to do is service the case as it gets full of hydraulic fluid. I maintained several 4 matics this way for several hundred thousand miles. I liked to service the transfer case when the hydraulic fluid had dropped a half quart.
Then to stretch this time frame in the summer or good weather you can flip the service valve and the system shuts off. Or on the 92-93 models move the electric switch to the test position. The car will operate in only two wheel drive. When the weather gets bad then move the switch back. Sometimes you can get a code for the stop lamp switch, which can easily be erased by either reading and clearing codes or unplugging the control unit for about 10 seconds.
By the way I love this system for the same reasons mentioned before. If you have good snow tires on this vehicle it is virtually unstoppable.

That doesn't sound to bad then. The chap selling tells me he had a warning light on the dash come on to tell him it wasn't working and that he had a Merc. Tech. to look at it. He put it on a computer and told him it was the transfer case leak. If I have it right all that needs doing is the fluid level topped up and then service the transfewr byt draining refilling and any filters changed. Is that correct. Sorry to be a pedant. Would driving it like this for the last 6 months have caused any further damage?

Actually there are people on this site who have some expertise in these matters:)i recommend changing the whole system over to use ATF as the hydraulic fluid for the 4matic ,pwr steering and SLS system.that way if you have a leaky xfer case it wont matter and should continue to function properly.if you have any other questions there are other sources for help as well.send a PM

If I remember correctly I used to use ATF in my Talbot Torqueflite Auto Box. I actually managed to rebuild that one but not recomended. I digress. Thanks for that interesting bit of info. Why does ATF work with a leak when the normal fluid doesn't? I haven't bought the car yet so is there a lot of work in converting to use ATF? Sorry to keep asking but I am trying to understand the problem as well as look for a solution.

I do not know about using atf for the whole system. Not the worst idea, but you still have to drain the fluid out of the t-case. It will overflow after a little over 1 quart of fluid extra goes in.

actually ATF is a bonafide hydraulic fluid.says so right on the label.my testimonial is ive been using it in my 4matic this way for over 5 yrs.at 400kkm no problems have arisen:)

I have no doubt what you state is correct. Does it not leak out? Why does ATF work with a leak when the normal fluid doesn't? Is there a lot of work in converting to use ATF?

First, a "leak in the transfer case" can be one of two things, I've got experience there, thus no longer any 4matics:

If it leaks fluid out of the case onto the outside of the case / on the ground, it will not affect the 4matic function. Mostly an inconvenience to continue wiping its butt and keeping the case full.

The more serious leak is hydraulic (control) fluid from the internal control servos to the gear oil, which will if serious enough not allow proper operation of the clutch servos due to the leaky internal seals / inadequate hydraulic pressure. This will require a complete R&R of the xfer case to repair and I don't believe it is optional as the fluid will continue to migrate into the gear oil whether you use the 4matic or disable it.

4matics aren't that hard to buy that work properly, I wouldn't spend any decent amount of money for one that has expensive problems. If it's already yours, then it's different, but don't buy it with problems especially if not completely defined. The 4matic computer can also be the problem, or any number of the several sensors, how much do you trust these people?

Now I am confused. Jeff looks like he has a lot of experience with that driveway list so perhaps I won't bother with it after all.