901 R&P math problem

[lv2race]

I just replaced the ring and pinion in my 901 transmission. I built a tool (thanks to Jim Williams) that allows me to measure the distance from the center line of the differential to the face of the pinion shaft. Now that I have the measurement I'm a little confused on what the measurement is I should be striving for.

The data I read off from the pinion shaft and ring gear are as follows:

Pinion Shaft:
01037
-0.19
3.65

Ring Gear:
01037
0.15
+0.30

On page R43 of the factory manual it shows a diagram where E is the distance from the center line of the differential to the face of the pinion shaft.

On page R23 of the manual it states "Determine the adjustment value E from the blueprint value R = 63.50 by adding or subtracting the value of machined deviation r which is marked on the pinion face." I would take this to mean that E = 63.50 - 0.19 or E = 63.31

It goes on to say "A basic approximation value (based on averages) of 64.70 mm makes it possible to predetermine the spacer thickness required. The difference between adjustment value E and the approximation value (64.70 mm) indicates the spacer thickness needed." In my case then the required thickness of spacers = 64.70 - 63.31 = 1.39 mm

On page R 42 it shows the etchings on the pinion shaft and ring gear.

For the pinion shaft:

1. Deviation r = -0.19 (?)
2. Mating Number = 01037

For the Ring Gear:

2. Mating number = 01037
3. Backlash = 0.15

Now, one question is what are the additional etchings on the pinion shaft and ring gear not mentioned in the manual. I believe 3.65 on the pinion shaft is the date of manufacture (March 1965). The number +0.30 on the ring gear is really confusing to me. If this is really deviation r (which I've heard it might be), then what is -0.19 on the pinion shaft?

So, what should my measurement read from the C/L of the differential to the face of the pinion shaft?

1. 63.50 - 0.19 - = 63.31
2. 63.50 + 0.30 = 63.80
3. 63.50 - 0.19 + 0.30 = 63.61
4. 63.50
5. something else?

Thanks for your help in advance.

Rob

[lv2race]

OK, I know there are some 901 experts out there to help me with my problem. Maybe they haven't read my post. Does anyone know any 901 experts that I can send my message directly to?

Thanks in advance.

Rob

[Geary]

Take a poll. I'm guessing

#2. 63.50 + 0.30 = 63.80 I have no guess about the -0.19

Personally, I'd go with 63.80, set the backlash at .15 (.006"), and check the mesh with bluing.

[lv2race]

Thanks for your input Geary.

Rob