8466 Diffs orientation

[Chilly]

Just built 8466 (2nd/3rd time) and the engine/wheels are not happy together.

Has anyone got one built, and could take a photo from underneath?  I'm particularly interested to know if the diffs at each end are the same way round or opposite.

Mnay thanks

[Aurorasaurus]

6 minutes ago, Chilly said:

Just built 8466 (2nd/3rd time) and the engine/wheels are not happy together.

Has anyone got one built, and could take a photo from underneath?  I'm particularly interested to know if the diffs at each end are the same way round or opposite.

Mnay thanks

I dont have one, but as long as the line between the two axles is not changing direction somewhere, the diffs should be flipped at one end. If you think about how turning the gears would turn the central shaft you can see why.

If you pick the model up and spin both the back wheels, do the front wheels go the other direction? Then you need to change one of the diffs. Otherwise the problem may be elsewhere.

Good luck!

[Timewhatistime]

http://technicopedia.com/8466.html

 

8466 uses the old style differentials (4 L), so their orientation does not cause the issues (if it is possible to turn them at all).

So the issues have other causes.

Probably, it is a good idea to consult the building instruction or to look close where there could be a mistake in the orientation of a pair of gears.

Edited March 28 by Timewhatistime

[anyUser]

40 minutes ago, Chilly said:

Has anyone got one built, and could take a photo from underneath?  I'm particularly interested to know if the diffs at each end are the same way round or opposite.

I haven't got one assembled but built in the past.
According to the photo that I took (from top) the differentials at the front and rear axles are pointing the same way.

[Carsten Svendsen]

20 hours ago, anyUser said:

I haven't got one assembled but built in the past.
According to the photo that I took (from top) the differentials at the front and rear axles are pointing the same way.

This is correct. Both 24T ends should be on the same side of the model

[Timewhatistime]

21 hours ago, Chilly said:

Just built 8466 (2nd/3rd time) and the engine/wheels are not happy together.

This isn't a particularly precise description of the issue, so every answer will be based on heavy (and maybe false) presumptions.

 

Once again: I presume there is a severe misconception about the old 4L differentials - they are cog wheels whereas the newer differentials are bevel gears. Only the latter ones cause the drivetrain to stuck when they aren't orientated correctly.

Images of the bottom and the interior of 8466 can be found online.

[Maaboo the Witch]

Here's an image of the innards of 8466, courtesy of Blakbird.

http://www.technicopedia.com/8466/8466guts.jpg

[MikeTwo9398]

You can easy check if the problem is the gearbox or the differentials.

Put you gear selector in a neutral position make sure the 3 driving rings are not inside one of the 16 tooth clutch gears (see the picture with the red circle pag 44.)

Drive the car.

If the wheels are not blocking then the axles + differentials are correctly mounted and there could be something wrong in the gearbox.

The orientation of these differentials does not cause the issue but the 12 tooth gears going to the main shaft could.

If the wheels are blocking it could be that the 12 tooth gear you add in step 4 page 15 or the 12 tooth gear step 14 pag 59 are mounted the wrong way.

These gears couple the wheel axles to the main shaft (which is coupled to the gearbox) between the wheel axles.

For the gearbox, only one of the driving rings should be in a clutch gear otherwise the gearbox will be block itself.

 

Edited March 29 by MikeTwo9398

[Chilly]

Thanks all for your thoughts.

The problem seems to be the gears added on page 59 are not staying where they should be, but are bouncing away from the diff.

I can't see that I've missed a step, but who knows without taking it completely apart.

I've solved it by adding a cross axle through the technic bricks, with a Technic Axle and Pin Connector Perpendicular 3L with Pin Hole
32068 joining the original axle in place. 

http://www.readypedalgo.co.uk/Lego Images/8466 - Page 59.png

Edited March 29 by Chilly

[allanp]

Glad you solved the issue.

Just to clear up a few things said in this thread, even though they are the older style diffs, it will matter which way round they go because if you have one installed the wrong way round, you will most likely have the mated 16t and bevel gears installed backwards also, which will make the main central shaft spin the wrong direction. Normally the diffs would go in opposite orientations front to back, but as the rear diff has an added gear stage of 16:16, this flips the rear diff so they should be orientated the same way in this model.

Also, installing one of the diffs in backwards will not block this model from rolling on it's wheels because of the central differential. All that will happen is the two axles going into that middle differential will freely turn in opposite directions and so the differential itself will not turn, making the gearbox and engine completely motionless in all gears.