020 GEAR RATIOS
Here I will try to cover the possible gears you might find in the 020.
A note on the way the tooth counts are listed....the first number is the driven gear, the second number is the driving gear.
A ratio is nothing more than a division problem, dividing one number into another.
You count the teeth on the gear that gets the power, the driving gear. You also count the teeth on the other gear, the driven gear.
Divide the driven number by the driving number to get the ratio, or the number of times it takes the driving gear to turn the driven gear one full revolution.
Example- 10:5 = 2
10 teeth on the driven gear, 5 on the driving gear, 2 turns needed of the 5T gear to spin the 10T gear one full time. The gear ratio then is 2:1, spoken as "2 to 1".
DRIVING gear is on MAIN SHAFT
DRIVEN gear is on PINION SHAFT
1st and 2nd Gears
In the 020, the driving gears for 1st and 2nd are machined directly to the main shaft or input shaft, meaning there is no changing those gears unless you change the entire shaft.
All of the 020 use the same 1st gear ratio.
38 : 11 = 3.455
For 2nd gear, you get one of 3 choices. *4-speed only
35 : 20 =1.750*
35 : 18 = 1.944
36 : 17 = 2.118
Don't forget with the main shaft, there are also 2 different diameters, 22mm and 24mm. The larger found on 16V and MK3 8V cars. There are only 5 codes with the 24mm main shaft, AGB and 2Y for the 16V MK2, and then AMC, CHE, and DFQ for the MK3 8V boxes.
3rd Gear
For 3rd gear, you get more choices, 5 in fact.
33 : 31 = 1.065
35 : 29 = 1.207
36 : 28 = 1.286
37 : 27 = 1.370
39 : 27 = 1.444
4th Gear
You get one more choice for 4th gear, for a total of 6 ratios. However, the 4th gears on the 16V and MK3 boxes (the 5 codes discussed before) have a larger diameter hole than the other codes, by 2mm.
This means if you run a 16V or MK3 (codes up to 01067) pinion shaft, you get 2 choices, 0.969 or 1.129.
MK3 codes after June 1st, 1997 can use other ratios, VW reduced the shaft diameter back down again after then.
30 : 34 = 0.882
30 : 33 = 0.909
31 : 33 = 0.939
31 : 32 = 0.969
32 : 31 = 1.032
35 : 31 = 1.129
5th Gear
The choices for 5th are more varied, you get 8 ratios to choose from. Keep in mind the 16V cars (and MK3 codes up to 01067) have a deep groove in the driven gear, and the 8V gear will fit on the 16V shaft, but cannot be properly secured. If you have a 16V or MK3 shaft, you are limited to the gears with the deep groove on the face (MK3 codes past 02067 can use the non-grooved gear).
27 : 38 = 0.711
37 : 52 = 0.712
38 : 51 = 0.745
44 : 58 = 0.759
33 : 41 = 0.805
34 : 40 = 0.850
42 : 47 = 0.894
31 : 34 = 0.912
Reverse Gear
There is only one ratio for the reverse gear in the 020, but reverse uses an idler gear. It is a 3rd gear that is moved to mesh between the pinion and main shafts, effectively making the trans have 3 shafts, which will reverse the direction of the ring gear in relation to the engine direction.
The main shaft is a 12T gear, the pinion shaft is a 38T gear, and the idler is a 20T gear.
20 : 12 = 1.667
38 : 20 = 1.900
When dealing with multiple ratios, you multiply the ratios together to get a final ratio.
1.667 x 1.900 = 3.167
This can also be expressed without the idler gear included...
38 : 12 = 3.167
Speedo Gear
Three choices for the plastic speedo gears.
The MK1/MK2 cars with the actual cable used a color coded gear system, but
with the MK3 cars, this stopped, and the colors no longer matter. On the MK3
cars, the electronic speedo gear will be a 15T gear, maybe red, maybe
white/gray, but 15T.
This makes it hard on the MK3 people who swap in a close ratio MK2 box with
a lower R&P set, because they can't get that other gear for their car.
15 : 7 = 2.143
16 : 7 = 2.286
17 : 7 = 2.429
For the MK2 cars, the color code system was...
15T = RED
16T = GRAY/WHITE
17T = GREEN
Ring & Pinion Gear
There are six options for a R&P set, but keep in mind that the 16V and MK3 8V boxes (those 5 codes from earlier) are all 3.667, the most common ratio. If you want a lower R&P for your 16V trans, plan on sourcing an 8V MK2/MK1 4th gear set to match the smaller diameter pinion shaft.
The number in (xT) is the speedo gear tooth count
62 : 17 = 3.647 (15T)
66 : 18 = 3.667 (15T)
74 : 19 = 3.894 (16T)
63 : 16 = 3.938 (16T)
67 : 17 = 3.941 (16T)
68 : 16 = 4.250 (17T)
67 : 15 = 4.467 (16T) Syncro
68 : 14 = 4.857 (16T) Syncro Country
In this pic, I've tried to label what goes where and mates to what. The Input or Main Shaft on the left, with the 1st and 2nd driving gear machined directly onto the shaft....the 3-4-5 set of driving gears, and the 3-4-5 driven mates....the Output or Pinion Shaft on the right, the driving Speedo worm gear, the big 1st and 2nd driven gears, the 3 reverse gears including the green idler...and the Ring and Pinion gears.
You can see the driven Reverse gear is actually the sliding collar of the 1st/2nd sync assembly, and the driving Reverse is machined directly to the Main Shaft.
Grinding reverse can chip and damage all 3 of those gears, which would mean a new Main Shaft, a new Reverse Idler, a new 1/2 Sync assembly, AND, because 1st and 2nd are machined to the shaft, it means a new 1st and 2nd gear set matched to the Main Shaft!
The helical design of the gear teeth cause the gears to want to slide away from each other. The direction of the gears under load is shown here...
Find your trans code on the bottom of the trans, in the yellow square in this pic... the numbers after the trans code are the manufacture date, listed as D-D-M-M-Y, for more info check the Oil Change page.
Chart covering MK2 models
Here is a ZIP file that contains an executable calculator that does 5 functions that can be handy for tuning. It was provided to me by Collin from Techtonics. It also contains text files with the ratios for the 02A, 020, etc... Download it by clicking here.
Here is a great page covering the codes, dates, and the country of mfg., taken from the A2 Resource site. Detailed charts covering the 020 and other trans can be found at http://www.a2resource.com/eandt/eandt.html
This listing is from the Techtonics ZIP file above, and should be more accurate...
"020" 4 & 5 Speed VW Gear Boxes
Code 1st. 2nd. 3rd. 4th. 5th. R&P Notes
GC 3.45 1.94 1.29 0.97 N/A 3.89 4 speed up to '80
GC,GN 3.45 1.94 1.28 0.91 N/A 3.89 4 speed from '81
GP,GL 3.45 1.75 1.06 0.71 N/A 3.89 3+E from '81
GY 3.45 1.75 1.06 0.71 N/A 4.17 3+E Pick up
FO 3.45 1.94 1.29 0.97 0.76 3.89 11/78-5/79
FF,FN,FH 3.45 1.94 1.29 0.97 0.76 3.89 Up to 07/80
FF,FN,FH,FJ 3.45 1.94 1.29 0.91 0.71 3.89 From '81
FM,FD,FK 3.45 2.12 1.44 1.13 0.91 3.89 Close Ratio
6G 3.45 1.94 1.29 0.91 0.71 3.65 Euro 8/82-7/83
7G 3.45 2.12 1.44 1.13 0.91 3.65 Close Ratio, Euro 8/82-7/83
2H 3.45 2.12 1.44 1.13 0.91 3.94 Close Ratio '83 GTI
4S,AOP,AGS 3.45 1.94 1.29 0.91 0.75 3.94 86-90 1.6 Diesel
4T,8A 3.45 1.94 1.29 0.91 0.75 3.67 Euro From 8/83
7A 3.45 1.94 1.29 0.91 0.71 3.94 From 8/83
4K 3.45 2.12 1.44 1.13 0.89 3.94 Close Ratio
4Y 3.45 2.12 1.44 1.13 0.89 3.67 Close Ratio 1.8 8v
9A,AEN,ACD 3.45 2.12 1.44 1.13 0.89 3.67 Close Ratio '85-'89
ACH 3.45 1.94 1.37 1.03 0.75 3.94 '85 1.6 Diesel
AGB,2Y 3.45 2.12 1.44 1.13 0.91 3.67 Close Ratio,16v
ACN,AON,ASF,ACL 3.45 1.94 1.37 1.03 0.75 3.67 1.8 8v
AUG,DGF,DGT 3.45 1.94 1.44 1.13 0.89 3.67 1.8 8v '90-'93
AWY 3.45 1.94 1.44 1.13 0.89 3.94 '90 Diesel
AVX 3.45 1.94 1.29 0.91 0.75 4.25 1.6 TD ECO
CHB,APW,DFN 3.45 1.94 1.37 1.03 0.85 3.67 From '93 1.8
CHD,DFP,ATH 3.45 1.94 1.28 0.91 0.75 3.67 From '93 1.9 TD 75hp
CHE,DFQ,DGD,AMC 3.45 1.94 1.28 0.97 0.80 3.67 From '93 115hp,Large input
shaft
4Z 3.45 1.944 1.286 0.909 0.745 4.467 02.86-12.88 Syncro AWD 020
ARM 3.45 1.944 1.286 0.909 0.745 4.467 12.88-07.89 Syncro AWD 020
ATZ 3.45 1.944 1.286 0.909 0.745 4.467 08.89-10.91 Syncro AWD 020
AXR 3.45 1.944 1.286 0.909 0.745 4.857
02.86-12.88 Syncro Country AWD 020
VW Motorsport 2.50 1.79 1.42 1.17 1.03 Std. Input Shaft
VW Motorsport 2.72 2.06 1.68 1.43 1.26 Large Input Shaft (16v & A-3)
02K
3rd 37/27-1.370
5th 32/42-0.762
R&P 62/15-4.13
VW Motorsport R&P options for 22mm Input Shaft Trans
4.20
4.46
4.64
4.81
5.07
VW Motorsport R&P options for 24mm Input Shaft Trans
3.32
4.20
4.46
4.64
4.81
5.07
Stolen chart from another site, thanks to whomever rightfully made this, but I changed the 4K R&P ratio to the correct 3.94 ratio, and the AOP 3rd + 4th ratios! I don't vouch for how accurate this chart is, there may be other errors!
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Gear Up! - online RPM-MPH calculator from www.Scirocco.org but it is the same chart as above, and contains errors.
A thread showing the Dodge Omni trans, which looks to be a VW 4 speed, thanks to Shrttrackr... http://forums.vwvortex.com/zerothread?id=3672899