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View Full Version : DIY: FWD to AWD Conversion



viziers
08-18-2010, 05:47 PM
List of parts needed for conversion:

AWD Transmission. (Make sure the gear ratios match between the AWD tranny & Rear Diff.)
Complete AWD rear subframe including Rear Diff + axels.
Complete AWD fuel tank including LPFP & Driver side Sender & heat shields.(it's very hard to get the heat shields with the tank from the salvage yard)
AWD Center drive shaft.
AWD exhaust. (you can either use a used stock AWD exhaust to save cost or go aftermarket.)
AWD Emergency Brake cable. (You can use the FWD cables, they hang a bit but work)

AWD system is MECHANICAL so no ECU or VAG changes are needed.....


Two things to note:
1. Make sure the final drive gearing is the same between the Transmission and the rear Differential ( I'll get the tranny & Rear Diff codes as soon as I can)
2. Make sure you have the SAME CV joint cups as to what is on your car currently or you might have to change them.


Here is the thread where it all started:
http://www.audizine.com/forum/showthread.php/285958-It-finally-has-begun-FWD-to-AWD



Order of events

1. Put rear of car on jack stands. Make sure the car is high enough in the air or you will have trouble getting out the rear pieces ( Rear end, Fuel tank & exhaust)

2. Disconnect battery.

3. Take off tire.

4. Take off exhaust and all brackets

5. Take the 2 bolts that hold the bottom of the shocks on off.

6. Now there are 3 electrical connectors connected to the rear end, Trace the 3 sets of wires from the axel (2wheel speed sensor & 1 auto leveling connector) the auto leveler is on the driver side so there are 2 electrical connectors on driver side and only 1 electrical connector on passenger side. You will need to take out the entire rear seat to get to the connectors, they are behind the side leather bolsters there are 2 nuts to loosen to be able to move the bolsters they bolt to the floor pan and there 1 obviously 1 on each side. You will also need to loosen part of both sides of the plastic under pans on each side to trace the wires. The first picture is where the bolt is that you will need to loosen in order to move the side bolster to get to the wire. The second picture is the hole where the wire comes up from the bottom of the car the driver side has 2 wires coming up through one hole and the passenger side only has the one wire coming up through the hole.

http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1712.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DriveSideInnerElectricalPlugPassThr.jpg

Driver side.
http://i600.photobucket.com/albums/tt89/vizierspty/DriverSideElectricalConnections.jpg

Passenger side
http://i600.photobucket.com/albums/tt89/vizierspty/PassengerSideElectricalConnections.jpg



7. Disconnect the E-Brake cable from both calipers. Now to make it a little easy you can do one of 2 things...the 2nd is easier but 1. Is to take the brake assembly off each side which may be difficult to get to the bolts with the shock in the way and 2. The way I did it is to disconnect the brake lines from the calipers and then remove the brake assembly when the rear is out of the car.
NOTE: FWD E-Brake cables are longer than AWD ones. The FWD will work or you can replace them with the AWD cables. It’s up to you.



8. This part is tricky if you are doing this in your driveway without a lift but it is still pretty easy for anyone (at least I thought it was easy) you will need 2 hydraulic jacks 1 one each lower control arm…..When you have the rear supported by that jacks you can then loosen the 4 main bolts that hold up the rear onto the car. IMPORTANT NOTE: You may want to compress the springs as much as you can with spring compressors before continuing on with removing the 4 main bolts I didn’t and had absolutely no problems, the springs gently released all their tension nicely as I lowered the rear out of the car.

9. Once all 4 bolts are removed and the rear is supported by the jacks you can the SLOWLY lower the jacks little by little alternating back and forth until they are completely down Being that the FWD rear is relatively light you shouldn’t have too much trouble sliding it out from under the car.


10. Now for the last piece... The fuel tank (Easier to remove the tank if you take off all the heat shields or whatever they are from under the rear as well as making sure there is as little fuel as possible in the tank obviously.)To remove the fuel tank you will need to put something like a jack to hold the tank up while you are removing all the hardware and it doesn’t come crashing down on you. (granted the tank is light depending on how much fuel is left in the tank) Once that’s done then you can remove the 2. ” fuel lines on the fuel pump then the 1. ” line on the fuel filter and the 1. 3/4” breather line on the tank and then there are 2. ” lines on the filler neck one on top and one on the bottom. Once that’s done then you will need to remove the rear passenger side inside wheel well to get at the filler neck. There are only 8 bolts to remove the fuel tank from the car. There are 6 that hold the 3 straps around the tank that hold it on the car and there are 2 on the filler neck. Once all that is done the the tank is ready to come out.
The 2 pics below show both the bolts and lines to remove.
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1722.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1723.jpg


The two pictures below are of the (top one) Fuel sending unit and (Bottom one) is of the fuel pump on a AWD tank. I’m currently just using the sender unit that is on the fuel pump side.
As for the fuel gauge I have not figured that out yet. That will be a work in progress type thing.
http://i600.photobucket.com/albums/tt89/vizierspty/Sendingunit.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/FuelPump.jpg

Putting it all back in is in the reverse order of how it came out..
1. Fuel tank
2. AWD rear end
2. Exhaust
There are 2 cross member bars on the FWD. There is the tunnel that runs from the front of the car to the rear. The front of the tunnel there is a roughly 16 inch flat bar in the front and a 7 inch bar in the rear. Neither bar will be for the QUATTRO car. The pic below shows the REAR cross member bar for the FWD I tried to use it but as you can see the QUQTTRO exhaust rests heavily on that bar. Not good!
http://i600.photobucket.com/albums/tt89/vizierspty/ExhausthittingCrossmember.jpg
For the front you will need the angled bar (AUDI Part # 8E0-804-813-C). The rear one will need to come off permanently as there isn’t one on the QUATTRO.

Once the back of the car is complete you can drive the car as long as you still have the FWD transmission in if you want to do this in two stages. The second stage of the conversion would consist of putting the QUATTRO transmission and the center drive shaft in.

11. Next you will need to install the QUATTRO transmission. I’m sure no explanation is needed on how to do that..

12. Now for the center drive shaft :
Note: Do not remove the end joints off and take them apart you WILL RUIN them if done so!!!
The center drive shaft is kind of a chore because you will need to relocate the mounting brackets shown in the picture below. Unless you know how to weld its best to let a shop do this part for you.
http://i600.photobucket.com/albums/tt89/vizierspty/0605091621.jpg


And that’s all there really is for the AWD conversion. If you have any questions just PM me and I’ll do my best to answer them for you.



P.S. If I forgot to mention anything please ask...[up]


Here are some extra pics:

http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1716.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1715.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1700.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1701.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/DSCF1702.jpg
http://i600.photobucket.com/albums/tt89/vizierspty/QTFurelTankinCar.jpg



vizi

wootwoot
08-21-2010, 06:25 PM
You are hardcore!

viziers
08-22-2010, 04:46 AM
You are hardcore!

Thank you, it was an easy challenge as I figured it would of been more difficult than what it was even working on a gravel driveway...Lol Now all I have to do is get the tuning finished then on to the suspension and maybe some spacers for the stock rims.... Gotta try to keep the sleeper status as much as possible....lol..


vizi



vizi

viziers
08-27-2010, 11:42 AM
SO um? I guess this is not technical enough to be in the B7 Tech as a DIY???? [confused]



vizi

nnnick
08-27-2010, 12:03 PM
I have a question for you vizi - how much did you spend on this total, and what are all of the parts needed?

Do you need a new ECU for Quattro to work, or can you just VAG-COM it?

Matt@EuropaParts
08-27-2010, 03:41 PM
Nice work Jeff. And yeah, this should be in the DIY/Tech section

Quattro
08-27-2010, 11:06 PM
looks so easy, going to do this tomorrow hehe

Leo14
08-28-2010, 01:35 AM
Ive been waiting for this! Yes! You rock my sox =P
Seriosuly speaking, thank you so much for this, I do have a few questions for you though. How long did this take you? On a scale of 1-10 what difficulty would you say this is? 1 being the lowest 10 being the highest obv. List of tools would be handy too :) thanks again!

EDIT: Would this work with the CVT?

viziers
08-28-2010, 04:15 AM
Ive been waiting for this! Yes! You rock my sox =P
Seriosuly speaking, thank you so much for this, I do have a few questions for you though. How long did this take you? On a scale of 1-10 what difficulty would you say this is? 1 being the lowest 10 being the highest obv. List of tools would be handy too :) thanks again!

EDIT: Would this work with the CVT?

Well, time wise it can be done in 1 to 2 days and on a scale of 1 -10 id say it was a 4 with the tools that I have, no special tools were used spring compressors would of been nice to have but not needed...

As for the CVT im not to sure on that one... Clint might be able to answer that question berrter than I can...



vizi

GA42.0T
09-02-2010, 08:48 AM
Amazing.

vdubjetta02
09-02-2010, 09:09 AM
think if i ever owned a FWD audi, i would just sell it for a AWD.....samething with if i had an auto. I would just sell the car to buy a manual

Dimitris_Kon
09-02-2010, 09:21 AM
You are mad Vizi! [wrench]



Dimitris

illegitimus
09-02-2010, 11:09 AM
A+ on the effort! I have a general question. Does the AWD transmission houses both transfer case unit and the center diff?

2007B7cabrio
09-02-2010, 12:21 PM
EDIT: Would this work with the CVT?

I'm pretty sure the CVT will not work in AWD setup, all teh quattro's are with manual or TIP (normal 6-speed auto), I have never seen a quattro with CVT

vizi, that is an amazing mod... nicely done

viziers
09-02-2010, 12:27 PM
think if i ever owned a FWD audi, i would just sell it for a AWD.....samething with if i had an auto. I would just sell the car to buy a manual


If you read my build thread you will see why I didn't sell her....


http://www.audizine.com/forum/showthread.php/285958-It-finally-has-begun-FWD-to-AWD

vizi

viziers
09-02-2010, 12:27 PM
You are mad Vizi! [wrench]



Dimitris


Ah hahaha thank you!!!!

viziers
09-02-2010, 12:31 PM
A+ on the effort! I have a general question. Does the AWD transmission houses both transfer case unit and the center diff?

Yes it does then there is the obvious "final drive/rear diff" at the rear aele.....



vizi

viziers
09-02-2010, 12:33 PM
I'm pretty sure the CVT will not work in AWD setup, all teh quattro's are with manual or TIP (normal 6-speed auto), I have never seen a quattro with CVT

vizi, that is an amazing mod... nicely done

That I think is correct you can only go FWD to AWD or CVT to TIP I think on the last 2... Oh and thanks!


vizi

SleeperAvant
09-02-2010, 01:48 PM
Sweet, but what about auto to manual?

viziers
09-02-2010, 01:51 PM
Sweet, but what about auto to manual?

Oooo, ya know, ya got me there i'm really not sure on that one man..... I'm gonna guess that as long as the bolt pattern is the same then yes...Lol...

I think it will be too much trouble seeing you dont have the "3rd" pedel....


vizi

Doctor
09-02-2010, 02:07 PM
You are mad Vizi! [wrench]



Dimitris

What he said

viziers
02-28-2011, 04:33 AM
So Moderators, when you gonna move this to the DIY section, or is this not DIY material for others!


vizi

GarrettReid
02-28-2011, 04:35 AM
I think this is probably one of the most substantial DIY's out there actually.

audinewguy
02-28-2011, 04:37 AM
welcome 2 quattro

viziers
02-28-2011, 06:01 AM
I think this is probably one of the most substantial DIY's out there actually.


Aww thanks man, but im sure are others like pnb's vrt build on a B7..


welcome 2 quattro


Thanks, been loving it for over a year now..... Now I just have to get the tune dialed in and i'm set!




vizi

GarrettReid
02-28-2011, 09:09 AM
PNB's vrt build is great, but this is a chance for us fwd's to become awd haha.

viziers
02-28-2011, 09:17 AM
PNB's vrt build is great, but this is a chance for us fwd's to become awd haha.




I can't argue that point! lol


vizi

viziers
03-05-2011, 08:12 AM
TTT!



vizi

b7kevin
03-05-2011, 08:33 AM
Really nice work here.

Spent a lot of time and money I'd imagine.

Shanks_26
04-18-2012, 06:30 PM
Sorry to dig this up. How much did this roughly cost?

schirm
04-23-2012, 05:38 PM
Sorry to dig this up. How much did this roughly cost?

X2

viziers
04-24-2012, 03:56 AM
Sorry guys, the build cost roughly 2500 initally until I sold the tranny and other parts the total cost went down to roughly 1500....I also took my time and sourced the parts as cheap as possible. The awd tranny I had bought had 19k on it compared to my 100k fwd tranny....




vizi

GA42.0T
04-24-2012, 07:32 AM
Any follow-up issues or anything to add to the DYI? Did you have problems woith the parking brake cable or fuel gague sender? Something like that?

shiro1745
08-03-2012, 08:03 AM
Any follow-up issues or anything to add to the DYI? Did you have problems woith the parking brake cable or fuel gague sender? Something like that?

x2

viziers
08-03-2012, 08:16 AM
Still have the fuel gauge reading slightly improperly but thats it everything else is still working without any issues.. I am still using the FWD parking cables as they are slightly longer but still work as they normaly do...




vizi

AudiA4_20T
08-03-2012, 09:25 AM
Still have the fuel gauge reading slightly improperly but thats it everything else is still working without any issues.. I am still using the FWD parking cables as they are slightly longer but still work as they normaly do...

vizi

You know how to fix that right?

viziers
08-03-2012, 09:27 AM
Yup, just have not had the time to do it...lol



vizi

Cherub
03-14-2013, 09:43 PM
Thank you for this. Next on my agenda

808_implant
01-04-2014, 09:23 AM
So I just had a major issue with my FWD 06 tranny due to the TCM crapping the bed and I think I have a donor car that's AWD. HOWEVER mine is CVT. Can you go from CVT to TIP with little issues? If there are issues what would they be? Also do you remember what any of the torque specs were for the bolts?