Fitting a 6 Speed gearbox to a 1.9TDi AFN?

[SyncroGhia]

Hi all,
I'm new to the forum but have found it very useful with lots of things I've been thinking about with my car.

I'm fairly happy with the way the car drives, (without the usual things of handbrakes seizing up!) despite it having done 282K! I've replaced the nozzles recently with T4 150bhp .216s and it goes fairly well while still giving 50+mpg.

I'm in the process of fitting cruise control to it, I'm hoping this is just a case of buying the stalk and then wiring it in to the ECU and 'telling the ECU' that it's now got cruise control... please correct me if I'm wrong!

The other thing I'm looking into is fitting a 6 speed gearbox to it.

The 5 speed is now a little tired, especially going into 1st from stationary and it generally doesn't want to shift cleanly. I'm looking at this as a possible time to upgrade and stick in a 6 speed gearbox from an A6 2.5TDi (AEL 5 cylinder). I have the gearbox codes and have plugged them into my gear calculator and it's all looking good. Having an extra gear which will drop the rpms down to 2150rpm @ 70mpg rather than 2500rpm should do good things for mpg.

Has anyone else done this? I think the gearbox has some of the shifter rods with it but not all and I don't have the shifter. Will it bolt in? do I need to make up mounts? with the CV joints match up etc etc?

Thanks in advance.

MG

 

[jcb]

is your car quattro? if so you need to match the box to the approprite final drive rear diff
box should mount but I knoe there were some changes to th box mounts from year to tear and you may have to play around to get the right combo.
certainly putting s4 6 spd into an a4 5speed is not a straight swap
if the cv's don't match it is an easy job to switch the box flanges

 

[aragorn]

The biggest issue you'll probably have is the nearside tranny mount.

On the 4cyl models this is a D shaped bush, that stands up off the subframe and mounts sideways to the tranny, on the 6 cyl models its a doughnut shaped bush that mounts vertically (like the offside one). I also wonder if the box your talking about (presumably from a C4 A6, as the C5 A6 didnt have any 5 cylinder engines) will fit a B5 without changing the mounting brackets?

Personally i recon the easiest fix would be to simply swap the entire subframe for one from a 6 cyl, however i know mark on here welded a suitable mounting onto his existing subframe when he converted his 1.8T.

The next issue is the flanges for the driveshafts. 2.5TDI will use the large 130mm tripod flanges, whereas your car will currently use 108mm round flanges. JCB says they're easy to swap, but i'm not so sure, i had a proper nightmare trying to remove the flanges from a box i was skipping.

I'm also not sure if the 5 speed box has the same driveshafts as the 6 speed, so you may need the 2.5tdi shafts, which might cause problems getting them to mate up with your uprights.

 

[SyncroGhia]

Thanks for your replies.

Sorry I should've made it clear, it's a 2WD.

The gearbox is from an A6 C4 2.5TDi 5 cylinder. I'm expecting the output flanges to be the larger size but was hoping that I could swap them flanges over from gearbox to gearbox.

I've not messed with V6 2.5TDi's so don't know the differences on gearbox mountings...

Having done some more research, my current gearbox is an 012 and the 6 speed is an 01E.

Has anyone done this swap?

Cheers
MG

 

[aragorn]

Ok, had the box been from a C5 A6, then what i said above applies, ie the subframe for a 4cyl model wont take an 01E box, so you'll need a 6 cylinder subframe, or youll need to crack out the welder.

The problem with the C4 is i've no idea if the alloy brackets (that sit between the transmission itself and the subframe) are the same as the B5/C5 ones. You may need to aquire yourself a set of brackets from a B5 or C5 model with an 01E box. I guess you could compare the part numbers on ETKA to confirm.

As i said above you will need to either swap the flanges or the shafts etc around to make it fit, and you'll need the linkage from a suitable car (again i've no idea if the C4 bits will work, or if you'll need to find B5 parts)