My fading memory of the original 4-speed that came in the Fox wagon is that it was barely adequate. It was work to drive. The car had to be driven hard to get out of the way of modern traffic. The intentionally under powered engine made the use of long gearing in the transmission necessary. The restrictive exhaust, small valves, small throttle body produced a fairly torquey engine that was pretty unhappy revving above about 4000 rpm. The Fox 4-speed lowers the engine speed by over 50 per cent as it is shifted from 1st to 2nd. The engine speed after the shift was too low to be near the narrow power band. The car always seemed to be straining when driven in anything but the most conservative way (A luxury seldom afforded when driving in the city.). An unsatisfactory arrangement for a spirited drive.

Gear Ratios of the Fox Four Speed. Type 014. Code PW.
This is one of the widest ratio transmissions VW produced. For comparison the ratios of the 1981 Rabbit GP transmission are shown. This comparison is to give a sense of where VW placed the Fox on its performance scale.

	Fox 4 PW	Rabbit 3+E GP
1st Gear	3.45	3.45
2	1.70	1.75
3	1.06	1.06
4	.78	.71
FD	3.89	3.89

I could see great potential in the Fox I was certain that replacing the 4-speed transmission with a 5-speed would help realize this potential. With the extra gear, part of the big hole in the 1-2 shift could be filled in which would improve the drivability of the car. The transmission would need to change as engine performance improvements were made.

Fortunately there are a number of possible transmissions to swap into the Fox. The Quantum, Audi 4000 and and some Foxes came with the type 013 5 speed transmission.

I had only had the car about 4 months when I decided that this modification must be done. Being new to the world of the Fox, I was quite convinced that all parts that fit a Fox were rare. As well, I was in a hurry to make the car more enjoyable.
This meant that I grabbed the first transmission that came along. A Fox 5-speed.

	Fox 4 PW	Fox 5 PSA
1st Gear	3.45	3.45
2	1.70	1.79
3	1.06	1.13
4	.78	.83
5	NA	.68
FD	3.89	4.11

The biggest difference between the two transmissions is the shorter final drive in the 5-speed. This moves the car through the gears faster. The slightly closer gears make it easier to drive in the power band. The engine is not over revving in a one gear only to be straining in the next. The car does not need to be driven as hard to perform at the same level.

I wanted to compare the Fox 5-speed to other VW transmissions and could not find one with similar gears. The Golf and Jetta of the late 80's used an AOP code  transmission.

	Fox 4 PW	Fox 5 PSA	GOLF AOP
1	3.45	3.45	3.45
2	1.70	1.79	1.94
3	1.06	1.13	1.37
4	.78	.83	1.03
5	NA	.68	.75
FD	3.89	4.11	3.94

 

Clearly the engineers did not have performance in mind when they selected the gears in the Fox 5-speed.
Of the transmissions available for the Fox the one with the closest ratios is the Code 2P from an Audi 4000.

	Fox 4 PW	Fox 5 PSA	GOLF AOP	Audi 4000 2P
1	3.45	3.45	3.45	3.45
2	1.70	1.79	1.94	1.94
3	1.06	1.13	1.29	1.29
4	.78	.83	.91	.97
5	NA	.68	.71	.80
FD	3.89	4.11	3.89	4.11

The close ratio transmission is hardly a close ratio gear box at all. Its numbers are very close to the "regular" transmission used in Golfs and Jettas.

A transmission that is sought after by Fox owners seeking to improve their drive is a 9Q that was found in the Quantum Turbo Diesel.

	Fox 4 PW	Fox 5 PSA	GOLF AOP	Audi 4000 2P	QTD 3M/9Q
1	3.45	3.45	3.45	3.45	3.45
2	1.70	1.79	1.94	1.94	1.94
3	1.06	1.13	1.29	1.29	1.29
4	.78	.83	.91	.97	.91
5	NA	.68	.71	.80	.73
FD	3.89	4.11	3.89	4.11	4.11

The relatively tight gears 1-3 plus the longer 4th and 5th offer the promise the combination of snappy acceleration with lower revs and better economy at highway cruising speeds.

Perhaps the transmission with the greatest performance reputation is the Code 2H from the 1983 GTi.

	Fox 4 PW	Fox 5 PSA	GOLF AOP	Audi 4000 2P	QTD 3M/9Q	GTi 2H
1	3.45	3.45	3.45	3.45	3.45	3.45
2	1.70	1.79	1.94	1.94	1.94	2.12
3	1.06	1.13	1.29	1.29	1.29	1.44
4	.78	.83	.91	.97	.91	1.13
5	NA	.68	.71	.80	.73	.91
FD	3.89	4.11	3.89	4.11	4.11	3.94

Another transmission that I was interested in looking at is the DHW used in the 1.8t front wheel drive Passats and A4s in 1997 and 1998. The motor in these cars was mounted longitudinally as well, leading to idle if expensive speculation that the transmission could be made to fit. The reason for this speculation is that Quaife makes a Limited Slip Differential for the DHW, and eventually I would like to have LSD in the Fox.

	Fox 4 PW	Fox 5 PSA	GOLF AOP	Audi 4000 2P	QTD 3M/9Q	GTi 2H	Audi A4 DHW
1	3.45	3.45	3.45	3.45	3.45	3.45	3.779
2	1.70	1.79	1.94	1.94	1.94	2.12	2.176
3	1.06	1.13	1.29	1.29	1.29	1.44	1.429
4	.78	.83	.91	.97	.91	1.13	1.029
5	NA	.68	.71	.80	.73	.91	.838
FD	3.89	4.11	3.89	4.11	4.11	3.94	3.89

It may not fit. It is hydraulically operated. It would be a PITA to fit. It does have an LSD available. Tempting.

There is an 014 (4-speed) box with tighter gears than any of the 013 (5-speed) transmissions. It was used in the early Audi Foxes, code ZV/ZS.

	Fox 4 PW	Fox 5 PSA	GOLF AOP	Audi 4000 2P	QTD 3M/9Q	GTi 2H	Audi A4 DHW	Audi Fox ZV/ZS
1	3.45	3.45	3.45	3.45	3.45	3.45	3.779	3.45
2	1.70	1.79	1.94	1.94	1.94	2.12	2.176	2.06
3	1.06	1.13	1.29	1.29	1.29	1.44	1.429	1.37
4	.78	.83	.91	.97	.91	1.13	1.029	.97
5	NA	.68	.71	.80	.73	.91	.838	NA
FD	3.89	4.11	3.89	4.11	4.11	3.94	3.89	3.98

Here are another couple of ways to look at the transmissions.

RPM Percentage Drop

	PW	PSA	AOP	2P	9Q	2H	DHW	ZV
1-2	50.7	48.1	43.8	43.8	43.8	38.6	42.4	40.1
2-3	37.7	36.9	33.5	33.5	33.5	32.1	34.3	33.5
3-4	26.4	26.5	29.5	24.8	29.5	21.5	28.0	29.2
4-5	NA	18.1	22.0	17.5	19.8	19.5	18.6	NA

RPM Drop (RPM After Shift @ 6000)

	PW	PSA	AOP	2P	9Q	2H	DHW	ZV
1-2	3042 (2958)	2886 (3114)	2628 (3372)	2628 (3372)	2628 (3372)	2316 (3684)	2544 (3456)	2406 (3594)
2-3	2022 (3978)	2214 (3786)	2010 (3990)	2010 (3990)	2010 (3990)	1926 (4074)	2058 (3942)	2010 (3990)
3-4	1584 (4416)	1590 (4410)	1770 (4230)	1488 (4512)	1770 (4230)	1290 (4710)	1680 (4320)	1752 (4248)
4-5	NA	1020 (4980)	1320 (4680)	1050 (4950)	1188 (4812)	1170 (4830)	1116 (4884)	NA

I plugged the gears and horsepower numbers from my first dyno run into a shift point calculator and came up with these numbers.

Shift Point with Same HP Before and After Shift

	PW	PSA	AOP	2P	9Q	2H	DHW	ZV
1-2	Out of Range	Out of Range	6402	6402	6402	6184	6339	6254
2-3	6134	6099	6016	6016	6016	5999	6053	6000
3-4	5912	5922	5954	5852	5951	5798	5902	5932

Maximum Area Under HP Curve

	PW	PSA	AOP	2P	9Q	2H	DHW	ZV
1-2	6494	6495	6500	6500	6500	6493	6495	6497
2-3	6495	6495	6497	6497	6497	4415	6494	6495
3-4	6496	6494	6500	4850	6500	4925	6499	6497

I'm not exactly sure if these numbers are useful for comparison but I thought interesting nonetheless. Perhaps most telling is the "Out of Range" on the Fox 1-2 shifts.

I'm much happier with the 5-speed than with the 4-speed. As the engine modifications produce more power I am becoming happier with the PSA 5-speed. If I had been more patient and selective I would have held out for a 2P transmission from an Audi 4000. The engine is now producing more power and is deserving of appropriate gearing. Still, I'm tortured by the idea that the DHW from an Audi A4 and a Quaife LSD could be squeezed into a Fox.
(Since this was written I have learned that Limited Slip Differentials for the 5-speed 013 transmissions are available in Brazil.)
If possible, mixing and matching gears from the 013 and 014 transmissions could produce a 5-speed approaching the characteristics of the 83 GTi 2H. A sort of ZV with a 5th gear and 4.11 Final Drive. That could produce a grin.