100 C4 2.5 tdi 5 speed, what else fits?

nuttinnew · 22-02-13, 02:23 AM

My father's got the aforementioned lurking about with a noisey gearbox. The oil's been checked and it's ok, guessing it's more involved in that so wondering what other box would fit e.g. A4/Passat that are good and plentiful.
Ideally I'd want to put a six speed from a similar car in there, but I won't hold my breath and I think the 130pd 5 speed has a very similar top gear ratio.
Another thought; is the five speed a six speed box minus a gear, so if it was taken out for a rebuild it could have it added?
I'm a bit sad it's off the road atm, it still starts and runs sweetly.

Thanks in advance for any help

PoloGaz · 22-02-13, 12:51 PM

From my research into this very subject I've found that:

The 5-speed CEP transmission and the 6-speed ARX used in the C4 2.5 TDIs are the same gearbox in terms of construction. From The diagrams in ETKA it looks like there is a casing extension to add the 6th gear, but I assume all the shafts would need to be longer. So not easy to upgrade a 5-speed to 6.

The 6 speed box is referred to as a '5+E' on ETKA, 5th gear is virtually the same on both the 5 speed and 6 speed. So you'd be better off with the 6 speed for sure if you're looking for more fuel economy. I checked the final drive ratios, and they are also the same.

I was looking for a C4 avant for a daily a while back and after my research I decided that it would have to be the 140bhp model with a 6-speed or nothing.

Ever been on club polo? I recognise the name

nuttinnew · 22-02-13, 03:46 PM

Thanks Gaz.

I sure have, you must have a good memory though because I had to change my username on there years ago! I've still got most of a G40 and a GT lurking about, stuff I really should use or sell.

Bah, I was hoping it was just a blocked gate and minus a cog

Iirc the 5 speed is something like 27.7mph/1000rpm and the 6 31.7, so a useful bit extra.

I may have some luck though, one's just popped up on ebay for breaking, fingers crossed it has a suitable box.
A6 C4 2.5 tdi saloon breaking

22-02-13, 12:51 PM	#2
PoloGaz Grown up member Classic Audi Club Member Join Date: Aug 2012 Location: Manchester Posts: 362	From my research into this very subject I've found that: The 5-speed CEP transmission and the 6-speed ARX used in the C4 2.5 TDIs are the same gearbox in terms of construction. From The diagrams in ETKA it looks like there is a casing extension to add the 6th gear, but I assume all the shafts would need to be longer. So not easy to upgrade a 5-speed to 6. The 6 speed box is referred to as a '5+E' on ETKA, 5th gear is virtually the same on both the 5 speed and 6 speed. So you'd be better off with the 6 speed for sure if you're looking for more fuel economy. I checked the final drive ratios, and they are also the same. I was looking for a C4 avant for a daily a while back and after my research I decided that it would have to be the 140bhp model with a 6-speed or nothing. Ever been on club polo? I recognise the name

22-02-13, 03:46 PM	#3
nuttinnew Newbie! Join Date: Apr 2010 Posts: 2	Thanks Gaz. I sure have, you must have a good memory though because I had to change my username on there years ago! I've still got most of a G40 and a GT lurking about, stuff I really should use or sell. Bah, I was hoping it was just a blocked gate and minus a cog Iirc the 5 speed is something like 27.7mph/1000rpm and the 6 31.7, so a useful bit extra. I may have some luck though, one's just popped up on ebay for breaking, fingers crossed it has a suitable box. A6 C4 2.5 tdi saloon breaking