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Old 04-10-2015, 06:48 AM   #1
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Lightbulb Audi transmission Swap


Hello 986forum ! I'm Ken. Here is a picture thread of a audi transmission swap I performed a while back.




Find yourself a donor. I found an audi a4 5speed manual transmission. Quattro will not work. Some VW passats will work too. S model boxsters can utilize a 5 speed transmission - but require a lot of modification, e.g. axle flanges, mounting hardware. There are forum members with 3.4 996 engines and 97-99 5 speeds. The swap I performed is practically a direct bolt up for 97-04 2.5s & 2.7s. It can be done with S models, or 3.4 etc.


Drain oil from old transmission, remove axle flanges- they are not compatible with 2.5/2.7 axles. But- interestingly audi flanges should be the same as S model chasis axles.


Remove Boxster transmission.



With boxster transmission removed, switch out axle flanges and swap all hardware between the transmissions.



Putting the Porsche flange in the Audi transmission.



Re-assemble

note: If you do not have M12x1.5x70mm (999-072-008-09) 'G' bolt location picture, it would be recommended to order and install
http://www.pelicanparts.com/techarticles/Boxster_Tech/37-TRANS-Drop/images_small/Pic4.jpg The boxster transmission has a stud in the case, whereas the audi does not. G bolt did not come with my car.

Total cost: $200
Results: Shorter, more aggressive gearing. First gear takes off like a bat from hell. Highway cruising in 5th is slightly more efficient compared to G86/01 5spd Boxster transmission.

Ratios:
Final Gear Drive 3.889
1st 3.778
2nd 2.176
3rd 1.429
4th 1.029
5th .838
(Similar ratios to G86/00 97-99 boxster, albeit shorter)

RPM Chart: (calculated with 255/40/17 tires)


Hope you guys enjoyed. Feel free to give me your feedback and questions.


Last edited by KenDFW; 04-10-2015 at 08:08 AM.
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Old 04-10-2015, 07:06 AM   #2
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why i pay a mechanic.
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Old 04-10-2015, 07:17 AM   #3
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Labor of love. Felt very satisfying turning the key, and rowing through the gears.
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Old 04-10-2015, 08:42 AM   #4
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Cool beans!


I'll have to try this the next time!

Have any more pictures of the two transmissions?

Any other things have to be swapped between the two transmisions ?

Valve bodies, connectors etc.

No codes plug and play?

Last edited by healthservices; 04-10-2015 at 08:52 AM.
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Old 04-10-2015, 08:55 AM   #5
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Trying to visualize the boxster trans, what is that hole on top of the audi trans? Make me want to go out and find one just to see the differences if any
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Old 04-10-2015, 11:46 AM   #6
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Nice work! Curious if there is a Audi 6 speed that would work.
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Old 04-10-2015, 03:15 PM   #7
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Originally Posted by healthservices View Post
Cool beans!


I'll have to try this the next time!

Have any more pictures of the two transmissions?

Any other things have to be swapped between the two transmisions ?

Valve bodies, connectors etc.

No codes plug and play?

Once you see the transmissions side by side, it is very self explanatory as to what needs to be swapped. The one thing you have to is the axle shafts. The gear shifting hardware is external and is held on by bolts. It takes 5 minutes to unbolt and move over.


No codes. If you have a tiptronic though, no dice.
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Old 04-10-2015, 03:19 PM   #8
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Trying to visualize the boxster trans, what is that hole on top of the audi trans? Make me want to go out and find one just to see the differences if any
The hole on the top is the speed sensor IIRC. I went and took the boxster's and stuck it in. I remember side by the side transmissions were very similar.
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Old 04-10-2015, 03:40 PM   #9
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Hai was thinking a tip trans. Lol this is still cool though. Thanks
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Old 04-10-2015, 05:56 PM   #10
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Cool thread Ken Thanks!
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Old 04-10-2015, 08:31 PM   #11
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Originally Posted by KenDFW View Post
note: If you do not have M12x1.5x70mm (999-072-008-09) 'G' bolt location picture, it would be recommended to order and install
http://www.pelicanparts.com/techarticles/Boxster_Tech/37-TRANS-Drop/images_small/Pic4.jpg The boxster transmission has a stud in the case, whereas the audi does not. G bolt did not come with my car.
It is fairly common for one or more of the transmission bolts not to be re-installed if the trans has been out of the car previously. Many of the Boxster Spec racing cars are running fine with only 4-6 bolts rather than all 8. My car has 5.

I'm not saying that this is a "best practice", so don't run out to the garage and start removing transmission bolts. I'm just saying that this happens so don't be entirely surprised if you find that your car has less than all 8.
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Last edited by thstone; 04-10-2015 at 08:35 PM.
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Old 04-11-2015, 01:31 AM   #12
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question - do you have confirmation that the audi flanges will work with a 6-speed axle (proper diameter, M10 fasteners, etc.)? thanks, trk.
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Old 04-11-2015, 07:37 AM   #13
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Okay, so besides the gear ratios, any other advantages to doing the swap? Durability? Weight?
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Old 04-11-2015, 07:38 AM   #14
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Absolutely awesome.

I've always wished the gears were shorter - and now there's an affordable way!
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Old 04-11-2015, 11:51 AM   #15
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Okay, so besides the gear ratios, any other advantages to doing the swap? Durability? Weight?
cost savings, try finding any Porsche at a "pick a part" junk yard or any self serve yard for that matter




Most places when they hear Porsche... there is the added "Porsche Tax" LOL

typical 5 speed transmission for a Boxster is north of 1k

Last edited by healthservices; 04-11-2015 at 11:54 AM.
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Old 04-11-2015, 02:39 PM   #16
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I was talking with the owner of Stuttgart Southwest and he said the 6 speeds used go for $1600 to $1800. He has 3 used 5 speeds for $900 each. To me the 5 speed seemed decent but the 6 speed has a much higher demand and therefore the much higher price.
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Old 04-11-2015, 06:12 PM   #17
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Cool thread. I think that swapping the 5HP19 Tiptronic from a Passat/A4 would probably be very similar.
I know that several members are looking at Audi engine swap possibilities. I'm wondering if the engine and transmission might as well be swapped together. I was under a V6 Passat with a ZF 5HP19 (Tiptronic) and it looked like an easy physical fit to put in a Box'. The 2.8 V6 is just below the power of the flat 6 2.5, so not the best option for the trouble. The 3.0 V6 and 4.2 V8 keep me curious though.
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Old 04-11-2015, 07:54 PM   #18
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5-speeds are pretty easily found for around $450-$650. Don't believe the $1000+ asking prices (6-speeds are a completely other matter). I bought my replacement 5-spd from a 986Forum member for $450.

$499
2002 Porsche Boxster 986 Manual 5 Speed Transmission Transaxle | eBay

$637
Porsche Boxster 986 2 5 5 Speed Manual Transmission Gearbox 37 | eBay
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Old 04-12-2015, 06:14 PM   #19
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question - do you have confirmation that the audi flanges will work with a 6-speed axle (proper diameter, M10 fasteners, etc.)? thanks, trk.
Hi Radium King! I have the old audi axles in my garage along with the oem bolts.

Boxster 2.5/2.7 uses 8mm bolts (That's why I had to swap axles)

So the Boxster S uses 10x50mm bolts
The 1.8 A4 FWD axle bolts are 10x48mm 12mm triple square head bolts

So- the bolts will work and screw in.

I can take measurements of the axles. If the audi axle pattern will work with the Boxster S cv joint pattern, then this will get interesting. There are 6 holes, and the bolts will thread.

It wouldn't surprise me as Porsche and Audi share some parts!
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Old 04-12-2015, 11:57 PM   #20
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cool. i ask because the torsen (similar to quaif) automatic torque biasing rear differential from a v8 audi will go into an audi 012 5-speed with just a bit of machining. apparently easily found at wreckers. the issue is that the diff will only accept audi axle flanges. apparently this is an issue for the 944 guys (they have an audi 016 in the back of their cars) put perhaps because they use 8mm axle bolts as well. otherwise a $200 solution to the $2000 limited slip issue.

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