gearbox / transmission that high rev problem at 70mph!

[broutta]

Hi all

I have been trawling on the forums for ages trying to figure out what is the best gearbox to use and what is the best thing to drop those revs down to a more reasonable level for cruising on the motorway at 70mph when you have a ABL AAZ 1.9TD engine

i currently have a 4 speed box so the instant thing i thought was to get a 5 speed box - and what i've read up on the links of gear ratios lovely people on here have put on here is that they are actually higher geared than the 4 speed boxs and the 4 speed boxs are a lot stronger - so no 5 speed box from a t25

Also from what i have read that putting in a 5 speed from a audi 80 T4 or passat etc requires a lot of tinkering (i'm not 100% sure of this as i have never found a 100% definite answer so if i am wrong please let me know!!)

one curious thing is that someone put on 14/195 tyres on which they said did help!


so my question has anyone put this on their 4 / 5 speed gearbox - if so what was it like and your experience?
https://www.vw-winkler.de/Gangradpaar-0 ... der-5-Gang" onclick="window.open(this.href);return false;
it says its a final drive 0.69 so should really make that difference!

[broutta]

Brickwerks said they would change the ring and pinion to increase all the gears... anyone got any opinion?

[discipleofsketch]

Do you know what gearbox code you have currently?

If it was from a diesel originally it will be lower geared (as in higher revs) than a 4 or 5-speed from a petrol.

By the way "final drive" is a different thing to "final gear"! The diesel boxes have a 5.something final drive and the petrol boxes have a 4.something. So there is something (but not a massive amount) to be gained to swapping, whether it's to another 4 or 5 speed.

I had also heard that 4-speed boxes are stronger, but to date I haven't heard of anyone breaking a 5-speed box!

Bigger tyres will also reduce revs, but once again not a massive amount.

Re-gearing is the only way to significantly reduce the revs on a T25 gearbox.

You might have already seen this:-

http://www.brick-yard.co.uk/VehicleSpec ... fo/gbx.htm" onclick="window.open(this.href);return false;

This also usefully shows you the estimated revs at different speeds with the different boxes (assuming stock wheels and tyres):-

http://rjes.com/html/gearbox_types.html" onclick="window.open(this.href);return false;

I'm no expert, but from what i've read, fitting a different type of gearbox e.g. passat/A4 requires custom work for the gear shifter, the driveshaft angles can be steep, and maybe mounting the engine lower?

Anyway, i'm just repeating what i've read over the years, i'm running a 5-speed box from a petrol, with stock wheels and tyres on my tdi conversion, cruising mostly at 60-65 while I save up for a rebuilt gearbox to bring the revs down. In the first instance i'm working on soundproofing so the high revs aren't so distracting!

[broutta]

Thank You!!!!

no i don't but i do believe its still the original one which would be a one of the 1.6TD so ABH or ABS which both have similar gearing

so if i go with that assumption until i can get underneath it (currently at my friends garage with the radiator out) the ring and pinion would be good as it brings the final drive down to 4.14 and change the 4th gear to one from vwwinkler ( not sure which one would be best as i would still want enough grunt in 4th to be able to pull while towing)
seems the cheaper option than putting one of these in https://www.vw-winkler.de/5-Gang-Getriebe-3H-074" onclick="window.open(this.href);return false; ?????

i need a new clutch so the gearbox has to come off and seeming as its out i might as well rebuild put a new box in

with the tyres like you say not a massive amount so not really worth doing until i need new tyres


what type / how are you going to rebuild your gearbox?

[discipleofsketch]

Thank You!!!!

no i don't but i do believe its still the original one which would be a one of the 1.6TD so ABH or ABS which both have similar gearing

so if i go with that assumption until i can get underneath it (currently at my friends garage with the radiator out) the ring and pinion would be good as it brings the final drive down to 4.14 and change the 4th gear to one from vwwinkler ( not sure which one would be best as i would still want enough grunt in 4th to be able to pull while towing)
seems the cheaper option than putting one of these in https://www.vw-winkler.de/5-Gang-Getriebe-3H-074" onclick="window.open(this.href);return false; ?????

i need a new clutch so the gearbox has to come off and seeming as its out i might as well rebuild put a new box in

with the tyres like you say not a massive amount so not really worth doing until i need new tyres


what type / how are you going to rebuild your gearbox?

I would be cautious about changing the final drive and the final gear, you don't want to over gear it.

Assuming I ever save up the cash (and it then doesn't get used for fixing other things on the van/ boilers/ house repairs) i'll be getting on Aidan's waiting list: http://www.aidantalbot.com/" onclick="window.open(this.href);return false;. Now i've got used to the 5 speed, i'd probably have that one rebuilt. Mine is a heavy family camper and the closer gear spacing makes for a smoother drive. I was going to have my 4-speed rebuilt, but it's now in the for sale section on here.

[broutta]

awesome!! this guy seems to stock the parts that i'm looking at on vwwinkler! also with a different 3rd (4th) gear ratio, like you said would be good to try and keep those gears closer for a smoother drive!!

i like the sound of the short shift he sells as well!

do you have a rough guess on how much he charges for a rebuild? i guess its going to completely depend on what you want doing

[gary1998]

cheapest and easier route is to increase tire size

read here first
https://club8090.co.uk/forum/viewtopic.php?f=41&t=135826" onclick="window.open(this.href);return false;

[broutta]

cheapest and easier route is to increase tire size

read here first
https://club8090.co.uk/forum/viewtopic.php?f=41&t=135826" onclick="window.open(this.href);return false;

thank you for that! i haven't seen such a detailed one before i will have a read of that one!

[toomanytoys]

What rpm is it pulling at 70 now??
Need to go look at what code is actually on the gearbox.. (If you don't know where you are starting from, you will waste a lot of time and money messing about)
then decide what tyre sizes you are going to run
If you are going to add more weight/hightop/tow with it etc then that needs to be factored in..
a 5 speed isn't necessarily higher geared.. depends on code..
Aidan can build whatever you want and can recommend what you need

a 4.14 final drive ratio is for much higher powered vans than a AAZ

Audi gearbox needs to be turned upside down and an adapter plate needed.. and again, may well be too tall gearing for the power of a AAZ

You could gear it to do 2000rpm at 70mph.. but its never going to pull it unless downhill and a stiff following wind..

Where in the world are you, as I guess you are not in the UK, or at least are from overseas..

Short shifter kits are made by me and I can supply direct..

[broutta]

no idea but high! i haven't got a rev counter
yeah i'm going to be under the car tomorrow so ill be having a look for it
its a devon poptop at the moment and ill be leaving it like that, i prefer them over the hightops

a 4.14 final drive ratio is for much higher powered vans than a AAZ

really do you think so? the guys at brickwerks said it would make the gears much more usable as at the moment 1st is almost unsuable bearing in mind its turbo and a intercooler will be going on and if i can afford it and figure out the plumbing a chargecooler........ so probably just a intercooler lol!!

The audi gearbox sounds interesting is there any discussions that you know of that you could link on? would it be from an audi 80? Also i have a 1981 diesel model and i'm finding out that it is fairly different to other models so would it be the same?

yeah i haven't contacted adrian yet as he looks like a busy guy and i don't want to waste his time by asking silly questions - i thought my stupidity would be best answered on here first. also i want to discuss and think about it thoroughly to ensure i get it right

I'm just down the A52 then down the A46 from you so about an hour and a half away lol. why?

brill i might be in touch about the short shifter then

[Aidan]

Michael T3 at Brickwerks ran AAZ with a 4.14 with standard gearing 5 speed on standard tyres on multivan and it worked, his engine installation was pretty tidy and sorted not to much compromised so it does work, but it's on the limit I reckon with that 5th gear combo I wouldn't go longer, just mho, but the gearbox is then tdi ready for when the aaz goes bang see Al's post below

[broutta]

Thanks Aiden!

[R0B]

Aidan not Aiden

[broutta]