All of the gasoline Syncro trannys are physically the same on the
outside, other than the locker or non-locker part. The 2 North American
models you mentioned only differ in the locker/non-locker option. The
letter code only tells you what the specific configuration was when it
was new. Most of the time it is still the same but Syncronuts sometimes
change the internal gearing and you have no way of telling this from the
outside.

Mark

Christopher Gronski wrote:

>Hi All,
>
>Now I should have asked this question before buying my parts syncro
>but I am just trying to anticipate any potential problems.
>
>Bentley 34.19 lists two letter codes AAK & AAN. If I have the wrong
>one in my parts van am I in trouble? Where do I find the letter code
>on the actual tranny?
>
>I'm moving from a '86 non-locker to an '87 locker recently (5,000
>miles ago) rebuilt by AA Transaxles.
>
>Chris
>
>
>