Early 4 matic transfer case mods - PeachParts Mercedes-Benz Forum

rwd4evr · #1 10-01-2019, 02:49 AM

I just saw a 1990 300e 4 matic for sale pretty cheap, $600. He says runs and drives excellent. Had a run in with a tree at some point and has a Plexi rear window made to fit. Anyway I don't care about that. I'm wondering if it's possible to manually select the 4 matic mode. If I remember correctly it has 100% rear, 80/20 r/f , and 50/50 modes. Can I have a simple set up with a switch or vacuum valve to choose it on my own? I want a winter beater but I like to spin tires(alot

) so unless I'm getting stuck I don't want the AWD at 50 50. Also will the center diff cry if I'm pulling the e brake to rotate the car? duxthe1 would be my guess for these answers.

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whipplem104 · #2 10-02-2019, 12:12 AM

1st off I doubt it still works. But if it does then you could wire up toggle switches to the solenoids and activate whatever you want. But it is all hydraulic and crazy expensive to replace parts so most of them are dead and the pumps have been run dry so long they dont work any more along with the rest of the system being 30 years old.
One of the main reasons I do not own a 1990-93 4 matic wagon is I cant find a tcase to replace it with. I had one years ago and it was awesome. I loved that car.

97 SL320 · #3 10-02-2019, 06:26 AM

A solution could be a 722.6 conversion with a ML ( maybe 98 ish cars too ) transfer case made by Borg Warner. This transfer case is a version that is also used by Ford.

To make this work you will need a 722.6 bell housing and torque converter to fit your engine. 722.6 main case, output shaft , coupling and transfer case + an aftermarket trans controller.

whipplem104 · #4 10-02-2019, 09:12 AM

There is not a left hand t case to fit in the car. They are all truck cases. THe cars only had right hand drop with 722.6
And they are all AWD.

rwd4evr · #5 10-02-2019, 03:12 PM

Yeah I don't want the later style anyway. Not a project trans swap car. But damn a manual old style t case car would rule. How would I test it? Gotta jack stand it I guess? If it's bad it just reverts to rwd right? I remember reading that the trans rear seal would leak and overfill the t case.

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duxthe1 · #6 10-03-2019, 07:39 PM

Its the piston applying the clutches in the t-case that leaks, overfilling the case. The early cases had a problem where the piston cocked in its bore resulting in the internal leak. There was a later updated case that supposedly had that issue fixed, but they still leak too, just maybe not quite as fast.

IIRC, the torque split is either 50/50 or 60/40.

Usaguy · #7 10-07-2019, 12:21 PM

Quote:

Originally Posted by duxthe1

Its the piston applying the clutches in the t-case that leaks, overfilling the case. The early cases had a problem where the piston cocked in its bore resulting in the internal leak. There was a later updated case that supposedly had that issue fixed, but they still leak too, just maybe not quite as fast.

IIRC, the torque split is either 50/50 or 60/40.

Do you know years of 4matic with upgraded transfer cases?

I'm also looking for a repair manual if it exists

Thanks

duxthe1 · #8 10-08-2019, 08:06 PM

I don't remember exactly, but my best guess at remembering is sometime in 1991. I'm not aware of a manual but I'm sure its buried in WIS somewhere. I will advise you however, its not even worth the attempt without all the special tools. The rebuild kit is expensive and you have 0 % chance (I've tried) of getting the seals installed properly without the tools. I'd considered making a set of tools but its been on the back burner so long its safe to say I'll never get around to it.

whipplem104 · #9 10-08-2019, 10:44 PM

They have all been replaced countless times. So the odds of an original being in a car are virtually zero. They were a 60k maintenance item. With the sway bars, balljoints and engine mounts and headgaskets and water pumps. That was my favorite car to hit my rack in the late 90s. It was a cash cow. I think everyone was a 5-10k repair order. And then no one ever said no.

Usaguy · #10 10-09-2019, 01:01 AM

Quote:

Originally Posted by duxthe1

I don't remember exactly, but my best guess at remembering is sometime in 1991. I'm not aware of a manual but I'm sure its buried in WIS somewhere. I will advise you however, its not even worth the attempt without all the special tools. The rebuild kit is expensive and you have 0 % chance (I've tried) of getting the seals installed properly without the tools. I'd considered making a set of tools but its been on the back burner so long its safe to say I'll never get around to it.

Thanks much for your comment I was able to find a overhaul manual written by a some guy and he explains in detail the special tools he had to make/source.

the overhaul kit is currenty a whopping $294 (just a few o rings, seals and gaskets if not available i would have to source some custom o-rings)

If I were to buy one of these cars I would just pull the drivetrain and regasket the motor, rebuild the trans and the t-case and maybe the asd diff too and would keep a spare valveblock and sphere.

I bet there are some flexible pressure hoses that I would bring to a hydraulic shop to have recrimped with new hoses