915 Gearbox Assembly

Hi Sreffen

The gear dogs inside are not lining up.  There is a special tool that you need to use to twist the gear for the dogs to match up and this involves twisting the gear on the spline that engages the torsion shaft.  in some cases it will not simply drop into place.  I suggest you get someone with training to do the work. 

Check the heavy maintenance manual.

Cheers

Hi, thing is, we have one guy who just had the line maintenance training but this was not taught.

The named tool is used to align the teeth, but we do not have the shown situation. This is about 5 mm above surface.

In our case it is only 0.5mm above which fits to the 4 dogs between overload and damping clutch being engaged or not.

I guess the part with ‚moving the propeller to engage the dogs‘ is the part and leads to the idea those 4 dogs have not to be aligned, but engaged.

I‘ll check tomorrow and show pictures.

double post

Steffen

Without the tool you will not get the gear to drop.  it is a very slight twist of the gear, while the prop shaft is bolted down to a bench, to spring the torsion shaft enough and allow the gear to drop the amount you need.  (twist while pushing down or tapping with a soft hammer) Some gearboxes will simply drop together, others will need the tool and twist to get into alinement. 

Cheers

Hm, I am nearly sure we are talking of different things.

As we understand the tool is intended to align the teeth of damping and overload clutch after reassembly of both clutches when the alignment of the torsion shaft does not allow the teeth to engage..

see first picture

Then you have the result as in your picture at the incorrect part.

We are already in there and it is not like the incorrect part of the image, we are at the correct part with one last half millimeter to go.

So my goal is to understand how the dogs (second attached picture) have to be positioned to each other.

Do they have to be to be between each other so they kan work as clutches, claws or how how to name it. Or are they used as distance elements and they have to be one top of each other?

Tests show, that with those dogs in between each other (see third image) will do the trick.

So if I turn the dog hub within the damper clutch a bit, it would fit.

if i just would understand what those dogs/claws are for, I would know what to do.
if they have to be aligned and not engaged, I have no idea what sense they are for and no idea how to solve my problem, because there is no other gap to get those 0.5 mm.

This all is very annoying to have no information to that in both manuals.

best regards and thanks for your patience,

Steffen