Are you shure it is a 8/31 did you count the revelutions or how do you know????

You should notice a diffrence......

B.t.w. glad you made it.....

4% higher in top gear and 4% lower in 1st gear?
Reckon you'd need a good rev counter to spot such a small difference...
ken

Yes, I myself counted the differential teeth - 31
As for the rpm, I've got a rev counter from Perfect Product (Belgium) and it has been working well.
OK, may be the 1st gear is a bit lower, as you say, the problem is I can't feel the 4th longer, like it was supposed...
By the way couldn't it be that gear boxes with a 8/31 differential (Dyane 6) can also be short like the 2cv6 ??!

vitor,
only if someone has taken it apart and swapped cogs around.
I've got 3 Dyanes on the road, 2 of which have 2CV gearboxes fitted and unless you knew which one still had the orignal gearbox, it's difficult to determine during normal driving.

Except that the Dyane gearbox is quieter, of course, without that nasty whine which so many late model 2CV gearboxes seem to suffer with at around 60 mph in top gear...

ken

OK, Ken, but shouldn't there be a difference when we're using the 4th gear? I mean, shouldn't the car run at 104 Km/h instead of 100 at the same RPM?
Thanks for your support.

During the weekend I'll make the final test (motorway driving).

So??????

OK, it's not the end of the world , but I'm not satisfied with the performance of this gearbox at top speeds. I expected less rpms and a bit more of top speed - what I got is really irrelevant...
So, back to the starting point - I found 2 gearboxes (Dyane and 2cv6) apparently both of them not working properly. The problem is we don't know if the 8/31 crown belongs to the matching pinion on the Dyane gearbox.
Someone said here that this set should be the same. Could that be a problem?
Thanks.

Vitor,
yes, it does, as the profiles of the pinions are not the same, even though they've both got 8 teeth.

In any case, a crownwheel and pinion set should always be kept together, since they were lapped together during manufacture.
They can be identified by the matching numbers engraved on them.
A pinion will also have the information regarding its depth of mesh engraved on it.

ken

Sorry Ken, I probably didn't explain the situation in an accurate way...
The Dyane gearbox's pinion belongs to this same gearbox, but we are not sure the 31 teeth crownwheel has been taken from the same Dyane gearbox.
Summarising, I've got a crownwheel whose origin I don't know, although I know it is the one I need to make a longer gearbox.
Following your instructions, I'm going to try to identify the matching numbers engraved on them - the crown has got some rusty spots, I hope the numbers are still there
Thanks a lot!

This is the lowest you can get from a 2cv/ami8.dyane6.......

So if you still want lower rpm you can yuse an old ami 6 gearbox (drummer!!)
or a Ln or lowest LNA (All A type)
Then you go to gs, gsa and the lowest of all is an Axel 5 speed......


More top speed has (almost) nothing to do with gearbox...... it has to do with horsepower, friction and earodynamics.......

If I was you I would make a sidewinder.........