Dave,
     You need to turn BOTH wheel at the same speed..
Its easiest taking the ring gear teeh and dividing by the
pinion gear teeth.  Your rebuilding the transaxle anyhow
so just open it up and count the teeth.
                                      Eric

David Marshall wrote:

>Volks,
>As a result of my transmission failure... not my month to say the least but
>hey... I need to install a new transmission in my camper.
>
>The tires are 215/85R16 - circa 30.3" tall
>
>With a GPS reading 100km/h, the tachometer says 3050 rpm in 4th
>
>The transmission is an AAN which is supposed to be 4.86:1 - same as any
>north American gearbox
>
>Both the transmission and front differential were rebuilt in 2000 in Germany
>so who knows what has been done to them R+P wise.
>
>Plugging these numbers into a calculator, this should result in (with a 0.85
>4th) 2840 rpm and not 3050.   If you put 5.43:1 in the calculator, it
>results in almost 3200 RPM.
>
>So, I figured I could tell by putting the van in 2WD (via decoupler) and
>lifting a front wheel and count how many times the drive shaft turns when
>you turn the wheel once.   less that 5 means a 4.86 and more than 5 is a
>5.43 right??? nope... I get about 2.4 turns of the drive shaft.  Now... in
>my garage I have a 4.86:1 front diff... same test (hold one flange while
>turning the other) results in about 2.4 turns of the drive shaft flange....
>what gives?   Without lifting the vehicle totally off the ground and locking
>all differentials and giving the wheels a revolution by hand, how are you
>supposed to tell?
>
>The last thing I want to do is install my spare AAN in there and have it
>breaking because the front R+P doesn't match.
>David Marshall
>
>Fast Forward Automotive Inc.
>4356 Quesnel-Hixon Road
>Quesnel BC Canada  V2J 6Z3
>
>Internet: www.fastforward.ca   Email: sales@fastforward.ca
>Phone: (250) 992 7775
>
>- Vanagon Engine Conversions and Accessories
>- Vanagon, Transporter and Iltis Sales and Importation
>- Electrical harness fabrication and customization
>
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