W124 - manual transmission problem - solution?

[Peter C1974]

I have a 1991 Mercedes Benz W124 200E, with factory fitted 5 speed manual transmission.

When I bought the car approx 4 years ago, the transmission suffered from a fault. Changing gears from 1st to 2nd gear caused a horrible crunch. Worn synchro, you say. But, the gearbox would not crunch when changing down from 3rd to 2nd. I ended up replacing the gearbox with a good used one but the problem remains. By changing gears slowly, with a pause between 1st and 2nd, the 2nd gear will go in without a crunch.

The gear lever and gearbox are linked with three selector rods, similar to this arrangement (found in older Mercs):


Each rod serves two gears. Each rod can be extended or shortened. If a rod is the wrong length, it becomes difficult / impossible to select a gear. By this I mean that the gear stick becomes difficult to shift to the left and right side gates, not difficult as in causing a crunch between gear changes.

Is it possible that the rod that relates to 1st and 2nd gears is the wrong length and consequently it doesn't operate the shift mechanism inside the gearbox properly, causing the crunch?

It is unlikely that two gearboxes would suffer exactly the same fault.

Any ideas please?

 

[grahamcol]

I'm going to go off at a tangent here. Does the box grind when selecting reverse or is it difficult to select first from rest ? If it does l'd be suspecting clutch drag.

 

[Peter C1974]

I'm going to go off at a tangent here. Does the box grind when selecting reverse or is it difficult to select first from rest ? If it does l'd be suspecting clutch drag.

Thank you for your prompt response.

The gearbox will happily select 1st and reverse gears whilst the car is stationary. The clutch is definitely not dragging.

 

[grahamcol]

I'll bow out now then Peter but I'll keep watching this thread with interest. I'm sure others will be able to assist and l wish you good luck with it.

 

[mattkh]

Inside the car and at the lower end of the gearchange lever, is the rubber shroud.
If possible, raise the shroud and put up a picture of the mechanism that allows left and right movement of the lever.

 

[Peter C1974]

Inside the car and at the lower end of the gearchange lever, is the rubber shroud.
If possible, raise the shroud and put up a picture of the mechanism that allows left and right movement of the lever.

I replaced the gear lever gaiter not long ago and I remember how the gear selector mechanism looks. These images are taken from the internet but my selector mechanism is the same.

 

[mattkh]

Thank you sooo much for the photos.
I would put some grease in any ball sockets/bushes you notice in use, when moving the lever left for the 1/2 gear.

 

[ajlsl600]

You must ensure that when u select Yr gears. The actual gear selector(on sincro hub ) firmly lands in its ident worn linkages can prevent this from . Happening