MB LAF710 getriebe problem near Weiden idObflz

[mb laf 710 medved]

Hi, when shifting from 4X2 to 4x4 and then starting moving, there was a blow from down, from that time I can't put back 4x2. When I give 4X2 it is neutral there (I can't shift gears at 4x2 only when 4x4 is). It happened before also, like the 4x4 wasnt shifted properly but never like that. Car is moving now with like 4x4 but is moving fast like 4x2..I think so.. .Im on Germany Czech border and not sure if its possible to continue the trip...
Is there some test how to find what is destroyed I can make here in wood? Thanks for all reminder...mj

[KU 65]

Lift the front axle and shift ones more.
Maybe it is only tense up.

[Nelson]

Hello,


it can happen that the four wheel drive doesn't shift correctly together with the reduction. When you shift thiis gearbox you have a direct mechanical connection to the gear of reduction/fast drive. But for the operation of the for wheel drive there is a spring in between (everything inside the gearbox). So when something doesn't fit the spring lets the four wheel drive clutch staying in position until it fits better. But you don't notice this in the driver cabin.

Usually this is caused by tension on the gearbox parts in moment of shifting, so the clutch doesn't like to move. To get it solved just stay in high gear, turn the steering to one side and drive some meters forward and reverse so that the different rpm of front axle and rear axle come to the point of free play without tension. Then the spring can move the clutch.

Lifting the front axle (like recommended before) works as well and follows the same idea of free play in the gearbox parts.


Nils

[mb laf 710 medved]

Thanks a lot for both responses. I did all of them. The result is still only 4x4 possittion. When I shift 4x2 and put some gears on, fast kardan is moving, but car not. I have a fear about rear differential... But Im not a mechanic . If anyone have any idea please let me know, thanks a lot...mj

[Nelson]

Are you sure that the external mechanic of the gearbox shifting switches correctly between the positions for >fast gear/4x2< and >neutral< and >reduction gear/4x4<? In past I had sometimes the problem that something in the shifting was disconecting step by step, so the mechanic didn't reach the final position and I could only shift between one of the gears and neutral. To fix it I had only to tight a screw or such... When the vehicle doesn't move at all in a correctly shifted gear something serious must be wrong.

With 4x4 you shouldn't drive too long on asphalt. The tension between the axles on proper ground is not good for the drive line on long term. An easy solution for driving on without the risk of further damage is to dismount the drive shaft to the front axle; then it doesn't matter on road if four wheel drive is on or not.


Nils

[Nelson]

Thanks a lot for both responses. I did all of them. The result is still only 4x4 possittion. When I shift 4x2 and put some gears on, fast kardan is moving, but car not. I have a fear about rear differential... But Im not a mechanic . If anyone have any idea please let me know, thanks a lot...mj

I am not 100% sure if I understand correctly: in 4X2 the drive shaft to the rear axle moves but the vehicle stands still? In this cas the problem is the rear axle. Probably it is not the differential, but one of the drive shafts from the differential to the wheels.

Nils

[mb laf 710 medved]

Thank you very much Nils for your interest about my stuck. I try to explain it more detailed. Now Im sure that only front shaft (kardan) make a move of the car. Only front diferential do the move of the car.

1. 4x2 position - properly shifted. If there is shifted some gear and I try to move...not possible, car stay on a place but main and rear shafts (kardans) are spining. Front shaft not...
2. neutral position - like before
3. 4x4 position - car is moving but only front wheels are working

It looks like the main and front shafts(kardans) are working good, even the rear shaft(kardan), but from there is something wrong. How you said rear axle...Tomorrow next dirty day
Thanks a lot I appreciate it. mj

[mb laf 710 medved]

Hallo, so I have bad news. My rear Halbachse is broken. So now Im in searching where to find one...