Check Transmission Ratio

There MUST be an on-line calculator to do this (maybe at the Spicer site?) but it sounds like a math word problem.

Assuming you have a stock, VW fourth gear at .89:1, that means for every one turn of the crankshaft, you get a 1.124 turn at the pinion. (1 and 1/8'th turn - it's an overdrive fourth)

Then, if you have a freeway flyer at 3:88/1, that means that it takes 3.88 turns of the pinion gear to get one revolution of the ring gear to thus drive the axle.

3.88/1.124= .29 turns at the wheel.   .29*360° = 104° rotation at the wheel for every single rotation of the crankshaft.

How's that sound?

(I may be all wet, here......I haven't done these types of calcs in a looooong time!)

From SAMBA -

For all Bugs with a tunnel type transaxle ('61 up) jack 1 rear wheel up off the ground turn the crank pulley until the timing mark of your choice is strait up. Mark the tire that is off the ground so you know where strait up is on it. Chock the car, put it in second gear, and release the e-brake. Turn the engine until the mark on the tire goes one full turn. If the crank is right back at the timing mark it is a 3.88 R&P, if it is 1/4 turn past the timing mark it is a 4.12 R&P, and if it is 1/2 turn past the timing mark it is a 4.37 R&P.

Or - 

To help identify 1961 and newer tunnel transaxle ring and pinion ratios, the ring gear teeth can be counted through the rear transaxle drain plug hole...

35 teeth = 4.38
33 teeth = 4.13
31 teeth = 3.88

Would either of these methods be affected by both wheels being off the ground?

The car is on jack stands now.

I'd put floor jack under one tire and jack it so it doesn't spin - since you are measuring only 1/4 and 1/2 wheel turn.

Al, does that really work?  What about potential differences in the 2'nd gear ratio?  Were they ALL 2.06?  (I checked my specs from Rancho and, sure enough, I've got a 2.06 2'nd in there...)   Mildly drug-addled minds want to know.......

And Mike - if you can't force something under one wheel to hold it (it doesn't take much strength to hold it in place) you could use a 36mm socket on the hub nut with a bat handle and piece of pipe.

The second gear is gonna be 2.06, so this will tell you the R&P.

The "freeway flyer" means different things to different builders though, so you'd still have to do the same operation in 4th to see if it's a 3.88 with a .89, a 4.12 with a .82. or—yikes!—a 3.88 with a .82. 

I am supposed to know what I have, but I'm going to try these steps and see for sure. Love this stuff.

Where's 'el Frazoo and his math abilities when we need him?

Math was never my strong suit - I managed to hire people to do that stuff for me!  Thank Heavens that they invented the scientific calculator while I was going for my Masters - Never would have graduated without it!  Still got my original HP25C!

best way is if the motor is out mark the input shaft and put it in gear [4th] or [5th] and push the car on the ground counting the wheel and input shaft revolutions

ask mitch,  that's how I found his 3.88 was actually a 4.37 final drive.