Long 5th Gear for TDI's service

depronman

A2OC Donor
With the advent of 6 speed gearboxes the long 5th gear addition to the Std TDI gearbox as some what fallen to the way side
However I had no need to change a perfectly good gearbox as it had no synchro issues and the clutch is fine, but the engine always appeared to be revving too hard at motorway speeds, so I have fitted a longer 5th gear to my existing gearbox.
I went with the 0.659 ratio gear set as this was going to achieve 70mph at 2200 revs (well give or take a few revs, but lets keep the number simple)
At the same time I also changed the gear box oil for Audi G 060 726 A2, the oil which came out of the gearbox was OK, but it was normal old school gearbox oil colour, where as the new oil was clear and it also feels and flows noticeably easer than the oil which came out. This as had a very positive affect on the gear change which is now noticeable smoother and lighter.
The gears are a press fit on the gear box shafts and I have had to grind the legs on a set of gear pullers to be able to remove the gears, they are to say the least 'on tight'
The owl job took me 5 hours, but at least 3 of these was modifying the gear pullers, plus it kept raining and then clearing up so that didn't help either (garage is full of OSS waiting to be fitted and therefore was out of bounds)

The finished result is everything that I had hoped for, quieter motorway cruising, engine now at or around 2200 instead of 2800
yes the A2 will not hold 5th gear at 35mph like it did before on level ground, its now just about 40, ideally changing up to 5th at 45mph if you are not in a rush or 55 if you are chasing it through the gears.
My A2 is a TDI75 AMF running my Depronman remap, which starts to pull strongly from 1800rpm, I wouldn't even thing about the longer 5th gear without the remap as the std map would simply not provide enough flexibility or torque to pull the longer gearing.

I spent some considerable amount of time sourcing the required gear sets, but having found the source that I used I am confident in the gear quality.

If anyone would like to get the longer 5th gear I will be happy to perform the gear box modification and oil change at the same time, for this you get a new set of 5th gear cogs, fitting and gearbox oil change using the above mentions Audi oil for £270, if you need a remap at the same time then I will do this for £20 as you will already be here.
 
Highly recommend this ratio as i have it on one of my TDI's and it really makes cruising much more relaxed.
 
I've just had the 5th gear upgrade and wanted to add a little review:

The first thing I noticed when I was driving home was how quiet it was. Gone was the high rev rattle that my 165k car has acquired. The engine is running at a much much lower speed than before and conversation in the cab was a lot easier than before.

I also noticed that if I was doing the eco thing and trying to run under 70. @65ish, the revs were at 2000, which is the sweetspot for economy Vs power. It's too early to give you any Fuelly figures yet, but running at the perfect rpm on the motorway is is going to push mpg up into the 70's for sure.
Also included in my install was a cruse control.
If you wanted to make your mpg savings complete, then stick your car to 65mph and watch the fuel gauge fail to move.

The best and most cost effective upgrade I've paid for on my car to date.
:)

edit: I will update with some mpg figures as soon as I get another long drive in at the weekend.
 
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Highly recommend this ratio as i have it on one of my TDI's and it really makes cruising much more relaxed.
Agree with this. However, when a later change of job meant less long distance driving then fuel consumption did increase a little (also had a remap at the same time as the gear change), so it can get a little annoying being stuck in 4th on B roads (or constantly changing from 4th to 5th and back again).
 
0.658 Bluemotion Gearbox user here and also find the longer 5th gear much more pleasant for long distance cruising.

It is possible to trundle along B roads in 5th too so long as you can get to a speed greater than 45mph, this is with a remapped TDI, much prefer the ratios, although it gets a little confusing for me as most thing I drive are Italian.. with far longer first and second gear ratios V the short german 1st gears.
Personally really enjoy being able to carry on applying the TDI torque over a longer ratio, less gear changes for most acceleration bouts,
Probably not faster, but a lot more satisfying.
 
Is this by any chance the ratio used as standard in the TDI90? I ask because it cruises at 70 at around 2200 rpm, as you say (the tacho and speedo needles are parallel in 5th).
 
I’m not sure what the gear ratio and diff ratio are in the tdi 90. I know it is longer geared than the tdi75
 
https://audi.7zap.com/en/rdw/audi+a2/a2/2004-248/3/311-311039/

Diff in both appears to be 61 / 18, but the gear ratios are as follows -

1;2;3;4;5
EWQ (75hp Tdi?) 34/9 ; 36/17 ; 34/25 ; 34/35 ; 34/45
GRJ (90hp Tdi?) 34/9 ; 33/16 ; 30/23 ; 28/31 ; 28/40

calculated (ratio : 1)
EWQ 3.78 ; 2.12 ; 1.36 ; 0.97 ; 0.76
GRJ 3.78 ; 2.06 ; 1.30 ; 0.90 ; 0.70

to compare - Paul's 5th gear mod is 0.659 / Bluemotion 0.658 - so effectively - all other things being the same, top gear rpm 86.7% of the normal for a 75hp gearbox and 94.1% of the 90hp top gear.
 
Thanks Robin, very interesting. To be honest, 70 in 5th is probably around 2300, not 2200 (it's 2000 at 60) so that'd make perfect sense.

As a plug for Paul's remap, I've found that my TDI90 will trundle along happily enough in 5th from 40, and I have been known to engage 5th at 30-35 when I'm sure I won't be accelerating, though I'd always change down if I wanted any meaningful acceleration, partly out of mechanical sympathy and, specifically, consideration for the DMF. It does mean that in slow steady traffic, though, I can use 5th more often than I used to for just trundling along.
 
Hi all, I'm new to tdi ownership and have acquired a 1.4SE 75 with 130k miles and good service history. Still learning about the car but it seems to struggle in 4th at 30 mph and will not take 5th at 40 mph. Is this normal? One more thing that I didn't notice on the test drive..... sometimes get a strange sigh / screech when I let the clutch out on changing down. Sometimes on initial start up. Not all the time. Is this a belt or something more sinister with the clutch or gearbox? Any feedback welcome.
 
Hi all, I'm new to tdi ownership and have acquired a 1.4SE 75 with 130k miles and good service history. Still learning about the car but it seems to struggle in 4th at 30 mph and will not take 5th at 40 mph. Is this normal? One more thing that I didn't notice on the test drive..... sometimes get a strange sigh / screech when I let the clutch out on changing down. Sometimes on initial start up. Not all the time. Is this a belt or something more sinister with the clutch or gearbox? Any feedback welcome.

When my TDI75 was in factory tune I had to take all 30-limits in 3rd, and all 40-limits in 4th. The ideal change-up points seemed to be no lower than 35 and 50mph. It lacked low-end torque, there was nothing much beneath 1800rpm, although you could potter along on the straight and level at lower revs than this.

Re your mechanical symptoms, a squeal from the starter motor on releasing the key from position III when the engine catches is commonplace and not life-threatening. Noises from the clutch on disengaging could point to the release bearing in the gearbox though, but I should point out I'm taking an educated guess at this point. Hopefully some more informed members will post up soon.
 
So to update my review after driving for a few days.
There are several long bits of road on the way to work and I've had no problem pottering along at 50. I can even pick up the pace and keep up with the car in front if they decide to go a bit faster. Acceleration isn't great, but it does do it. It does hold this speed up an incline as well, but refuses to pick up speed. The couple of times I've tried to go to go to 5th at 45 were unsuccessful, as the rattle from the engine was worrying me.

What has made for interesting driving is the other end of the scale. Putting your foot down at 80 was quite exciting as the engine still has lots of torque left to deliver and it really pulls, a very enjoyable upgrade for a 17 year old car. I don’t do this very often I hasten to add, it was just for testing purposes ;-)

Still don’t see any downside to this upgrade and can only recommend it.

I have a 500 mile drive this weekend so hope to come back with some mpg figures.


Edit: my longest straight drive in 5th gear was 212 miiles, which was 12.02 liters of fuel = 80 mpg
That was using cruise control to stick to 65, stepping up to 70 to overtake.
 
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The couple of times I've tried to go to go to 5th at 45 were unsuccessful, as the rattle from the engine was worrying me.



Sent from my ONEPLUS A3003 using Tapatalk
This could well be your driveshafts rattling I had the same symptoms as did deproman (Paul) we both changed the joints for J&R ones & it did cure the rattling
 
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One more thing that I didn't notice on the test drive..... sometimes get a strange sigh / screech when I let the clutch out on changing down. Sometimes on initial start up. Not all the time. Is this a belt or something more sinister with the clutch or gearbox?
I too have this noise, at a guess it might be the sleeve thing inside the box am sure deproman could confirm this when he reads it

Sent from my ONEPLUS A3003 using Tapatalk
 
This could well be your driveshafts rattling I had the same symptoms as did deproman (Paul) we both changed the joints for J&R ones & it did cure the rattling

I'm not sure I described it right, it wasn't really a rattle, more a vibration.
The problem is that I've spent my last ten years driving a petrol engine and a very small one at that. I'm so used to having to have it at 3k + revs to be able to do anything, I think I was afraid of having 1500rpm, it might stall, lol
I have been experimenting several more times on the run to work and it does indeed go down to 45mph in 5th, but refuses to accelerate from there. It’s still taking me time to adjust to diesel, changing up early and getting into as high a gear as possible, as quickly as possible.
Still loving my new (old) A2
 
Still don’t see any downside to this upgrade and can only recommend it.

I remain a fan of the longer 5th setup, despite now having a 6-speed 'box. However, I'm adamant that it needs to be thought of as a change rather than as an upgrade. It's a compromise solution that provides some pros and some cons; whether or not it's suitable for you depends greatly on your use of the car.
I predominantly do motorway miles, so my previous longer 5th setup would frequently save me money due to the increase in fuel economy at motorway speeds. However, I also do a fair amount of driving in mountainous areas, where I would essentially only have 4 gears due to the longer 5th being inaccessible in such environments. In these circumstances, the longer 5th ratio would effectively cost me money. On the whole, I saved, but many A2 owners with the longer 5th find that their average fuel economy does not go up by much, if at all. Sometimes, all that's gained from the mod is a quieter drive when motorway cruising - which alone can be a good justification for the change.
Personally, I find the longer 5th is a down-grade in terms of the vehicle's 'driveability'. On a winding A-road (or in a 50mph speed limit on the motorway) I found managing the larger gap between 4th and 5th really tiresome. When doing longer cross-country routes, I found it quite draining to have to continually choose between rev'ing it harder in 4th or spluttering slightly in 5th; it requires much more concentration on an aspect of driving that's normally a subconscious process. Low-rev, high-load scenarios (such as trying to accelerate from 45mph in longer 5th) are terrible for your engine and gearbox, meaning the lower limits of the longer 5th's capabilities ought not be explored too often.
For those who use their A2 almost exclusively as a motorway cruiser, it's a very good option; compared to a 6-speed 'box, its pay-back time is relatively short and it makes driving at speed a whole lot more comfortable. But it's not without its drawbacks.

Cheers,

Tom
 
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With the advent of 6 speed gearboxes the long 5th gear addition to the Std TDI gearbox as some what fallen to the way side
However I had no need to change a perfectly good gearbox as it had no synchro issues and the clutch is fine, but the engine always appeared to be revving too hard at motorway speeds, so I have fitted a longer 5th gear to my existing gearbox.
I went with the 0.659 ratio gear set as this was going to achieve 70mph at 2200 revs (well give or take a few revs, but lets keep the number simple)
At the same time I also changed the gear box oil for Audi G 060 726 A2, the oil which came out of the gearbox was OK, but it was normal old school gearbox oil colour, where as the new oil was clear and it also feels and flows noticeably easer than the oil which came out. This as had a very positive affect on the gear change which is now noticeable smoother and lighter.
The gears are a press fit on the gear box shafts and I have had to grind the legs on a set of gear pullers to be able to remove the gears, they are to say the least 'on tight'
The owl job took me 5 hours, but at least 3 of these was modifying the gear pullers, plus it kept raining and then clearing up so that didn't help either (garage is full of OSS waiting to be fitted and therefore was out of bounds)

The finished result is everything that I had hoped for, quieter motorway cruising, engine now at or around 2200 instead of 2800
yes the A2 will not hold 5th gear at 35mph like it did before on level ground, its now just about 40, ideally changing up to 5th at 45mph if you are not in a rush or 55 if you are chasing it through the gears.
My A2 is a TDI75 AMF running my Depronman remap, which starts to pull strongly from 1800rpm, I wouldn't even thing about the longer 5th gear without the remap as the std map would simply not provide enough flexibility or torque to pull the longer gearing.

I spent some considerable amount of time sourcing the required gear sets, but having found the source that I used I am confident in the gear quality.

If anyone would like to get the longer 5th gear I will be happy to perform the gear box modification and oil change at the same time, for this you get a new set of 5th gear cogs, fitting and gearbox oil change using the above mentions Audi oil for £270, if you need a remap at the same time then I will do this for £20 as you will already be here.
I need to have this mod done, would you be able to do it for me?

rob
 
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