snmglk

Hi,

I am trying to do a test can the GLK 250 BluTEC 4MATIC be driven with the FWD shaft only, so removed the RWD shaft. This is to mimic a situation that can happen driving a vehicle off road and damaging the RWD shaft/transmission box.

The vehicle however can take off but when the speed is >1200 rpm it does not respond to the increase in speed/torque demand and brings the speed to 0 and it can be heard that the gears are disengaged.

Has anyone had similar experience and can you please have any suggestions?

GLKKa2H

Yes - don't do it! The GLK is, in accordance with MB statements, a SUV. As such, the off road capabilities are limited, even with its 4MATIC.

ble2716

Good advice.
I won't do it.

MKenM

And you want to do this for what reason?????????????????

snmglk

Thanks for answers.

The question is more was anybody driven the GLK w/o RWD shaft? As explained the car does not want to drive above 1200 rpm as transmission kept 'slipping' and not engaging the gear.

The reason for testing the car like this is to access a potential situation when the RWD is damaged either on or off road and can the car then be driven. If not then this raise some serious questions about what to do if the above situation with RWD happened, why having 4MATIC vs RWD, etc.

The driving w/o RWD shaft can potentially be tested on chassis dyno/rolling roads but again can this car be driven on a single shaft chassis dyno?

rmfnla

Sounds like a great way to #*&% up a perfectly good car...

MKenM

dgiturbo

Look up how 4-ETS and the 4MATIC works on the MB website and you will see why this won't work. Also the scenario you are describing is unrealistic. If you receive so much damage off road as to destroy the rear drive system, ANY vehicle will need to be towed as there will be severe undercarriage damage.

As for the single axle dyno testing, MB places a sticker under the hood that says something like: vehicle equipped with permanent 4 wheel drive, single axle dyno testing is impossible.

bop11

If you remove the rear drive shaft and allow the flange to free wheel, the transfer case/computer will still try to torque vector to both forward and rear shafts. Since the rear is unrestrained, the transfer case will try to vector all the torque to the rear shaft which will spin as in an old fashion differential. In some cases the brakes are used to do the vectoring, which means even if it does vector some to the front, you will be dragging the rear wheels. Restraining the rear shaft from turning will absorb the torque as if it was connected to the rear differential and wheels. However, since vectoring is around 50/50 ±10% this means half of the engine torque is taken by the restraining device. The question is how do you make something absorb this large amount of torque since there is not a real frame on this vehicle?
If you are worried about this happening, carrier a secondary drive shaft. More probably you will land on a rock with the exposed axle shafts and bend one of those. If you want to play hard, get a truck with enclosed axles and high vented locking diff's.
More likely you are going to run a hot wheel bearing into water and as it cools suck the water into the bearing.
Rock sliders or strong running boards and heavy duty under pans can help keep your shafts straight and the oil pan/ tranny exhausts and fuel tank solid. Since the change over from solid axle and body on frame UTE's, not much less than pickups are really suitable for hard off road.

DadinWestcheste

That's why they make Jeeps for rock climbing. I loved my CJ! SUV's on a car chassis, even with extra lift don't go over rocks very well.
I'm sad too. I love off roading....

rmfnla

SUV on a car chassis handles better than a Jeep.

Can't have everything...

bop11

For some reason the rest of the world gets the off road stuff. Land Rover Defenders, Toyota's, Isuzu use to makes good stuff, they are no longer imported. Why do I want an air bag when I expect to hit a tree every now and then in the woods? I guess you're right Jeep is all that is left in this part of the world.
SUV's on car chassis might handle better, but from what I see unless you teach people how to drive they are no better than the '63 Bonneville I had. What a beast.