Differential gear.
Turbo Mini Forums

Is there any differents from this,
http://img74.imageshack.us/my.php?image=pict3902no7.jpg

To this,
http://img234.imageshack.us/my.php?image=pict3901dl9.jpg

The 1st one is from a metro turbo, which i only have 1 of.
Not sure where the first 2nd one's from. But i do have 2 of them.
So yes maybe silly question. but what is the different's.
And can i still use the 2nd one in a turbo engine with my 4 pin diff

Cheers lads :)

A similar Q was posted on a different forum a while back. First, was the findings of the original poster after further investigation:

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The gear thickness of both output shafts is the same, not counting the raised section.

I was building a cross pin diff. when this issue came up. Just from looks, I tested the diff with the raised section output shafts first. The cross pin diff. turned into a locked diff as soon as I bolted on the crown wheel! Using the output shafts without the raised section solved the problem.

However, that still leaves the question open about what were the two used for?

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Then I did some investigating - here were my conclusions:




Ok, here is my findings...
Out of all my outputs, I have 7 of the style with the lump, and one without the lump - but don't srap any conclusions from the numbers; these are just 'odd ones'...

However - almost all my 'kit' is A+ stuff, and I'd say the majority is 1275 metro and 998 mini stuff from 1985 thru 1990.

Here is a picture showing what I KNOW came out of a 1990 998 metro - and is also the same as what came out of a 998 mini trans...

You can see where the raised part gently rubs the centre 'distance piece'.

I've nothing else to add on why the difference is there however, other than the 'distance piece' is clearly turned from hex bar, and appears to be a nice round 23.00mm... Maybe it was all originally designed at 25.4mm (1") and the extra little bits are to take up this clearance because they couldn't get - or for whatever reason switched from 1" to this wierd 23mm AF hex bar???

I guess it could also be that they switched to the smaller hex bar, and added the extra 'bit' onto the outputs because they were getting fretting or other such oil/metal contact issues on the centre of the output because of the large contact area, that would have been an intermittent wiping surface. By switching to a smaller hex, and adding a little extra onto the outputs, a continuous contact surface is formed, hence eliminating the intermittent wiping...

Other than that - I've no idea!

EDIT - I just measured the height of these 'humps' at a little under 0.7mm - hence, 2x0.7mm = 1.4mm.

1.4mm + 23mm (the distance piece) makes me think my theory is right... ie - the distance piece originally was 25.4mm AF, and they discovered problems with the intermittent wiping of the face. Instead of making too much of a change, they left a little more on the face itself, roughly the same diameter as the width across the flats on the (now smaller) hex.

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Basically - if you use the A+ spacer block on the pin, then you need to use the type with the dimple - ideally...

You say,
I was building a cross pin diff. when this issue came up. Just from looks, I tested the diff with the raised section output shafts first. The cross pin diff. turned into a locked diff as soon as I bolted on the crown wheel! Using the output shafts without the raised section solved the problem.
So that mean i cant use the ones with the hex head ?

Whats a A+ spacer block on the pin?

Sorry to be so impatient, but if i cant use the ones with the hex thing on top of the output shafts, then why didn't the company i brought the x pin diff off of, tell me this ? cheers.

Anyone.. ? impatient bastard i am yes lol

Hi dave,
Ive put it all together using the one with the hex top part, and it moves around ok.
When you say The cross pin diff turned into a locked diff. do you mean it didn't turn at all ?
How smooth shall it be.. ?
Cheers..

I suggest you read my post. It is clear that the first paragraph bewtween the * is what the other dude says.

Well he must of done something wrong then lol coz it works ok fot me.. :)
anayway, cheers dave