superman22x

Coming accross the 01E discussion thread reminded me I should post over here the details of my 01E swap.

I know this question has come up many times, with not many conclusive answers: Can one swap an 01E into a 944? Answer - Yes.

I figured I would share how I did this swap and some of the difficulties I had. I did this swap following a member of 944hybrids, "LSA_944." I'm not sure he posts over here at all. The main reason I did this swap is to supplement the LS3 powerplant in my Porsche. A 951 transmission would have been the easy answer, however with prices going up on those, an 01E was cheaper for the transmission itself. I paid 500 euro shipped to my door from Germany. The other advantage is the ratios are much better matched to the LS3, and the 01E I believe is rumored to be good for a lot of torque. This particular one comes from some sort of TDI.

The big downside to doing this swap for most people is that it requires custom machining some bits and pieces. If you don't have a mill and lathe, it might quickly get more expensive than just buying a 968 transmission... I have a mill and lathe, and enjoy the project, so it works out for me.

Onto the details.

What do you need for the swap?

• Custom Mounts
• Custom coupler from Audi splines to 944 splines
• Custom Length Axles
• Custom Shift Mechanism

Bolt Pattern - The 01E bolts up to the torque tube no problem. Different length bolts will be needed from the 944 is all.

Mounts - These can be done many different ways. I won't cover much here. I used the early mounts with some plates bolted to the side of the transmission. LSA_944 used the late style mount. Either way works.

Custom coupler - This is where the lathe/mill comes in handy. I cut a 944 coupler in half and press fit it into a chunk of 4140 I machined to fit. I used 3 alloy dowel pins that are press fit around the circumference to hold this together. I know this seems minimal, but according to the double sheer strength at that radius, it's good for around 2400 ft-lbs of torque. In comparison, the 1" input shaft of the 01E should fail at 800 ft-lbs. So, they shouldn't be the weak point of this setup.
The other end I bolted the center section from an Audi S4 clutch hub. This end was slip fit to within 0.001" to avoid any concentricity issues.





Custom Axles - The driver side axle needs to be about 0.5" shorter. The 944 axle flanges fit and bolt right in to the 01E. They stick out about 0.25" further, but the sealing surface still rides on the seal just fine, so I see no issue here. LSA_944 trimmed his down I believe.
In my case, I have an early car, and both my axles are 16.25" There are VW axles that are 15 5/8" that would work for the driver side. Typically aftermarket axles put about 2" of splines on them, so it would be easy to cut down 16.25" aftermarket axles. I found a chunk of 4340 at my local steel supplier in the cut-off bin, so I made my own axles and had them through hardened. If you are looking to do axles your self, you can get prehard 4140 from McMaster.

Custom Shift mechanism - Again, this is where a mill is useful, but a fabricator could make one without a mill. I tried multiple iterations here. The 01E has a hole in a similar location as the 944 transmission for the shifter shaft. However, it's a smaller diameter and in a slightly different location. What I ended up doing to make this work was opening the hole up with a die grinder, cutting 5" off the 944 shifter shaft, and feeding a bent rod through. Otherwise, the mechanism is very similar to the 944. Hopefully the pictures explain this a little better.

These pictures are before I opened up the hole with a die grinder.







Speed Sensor
The 01E speed sensor can be wired directly to the 944 speedometer with a pull-up resistor from the 12V pin. I believe the late 944 is a 3 wire sensor (my car is an early with late dash, so I had to wire this myself), the 01E is 2 wire. So just use a pullup resistor from the 3rd unused wire to the speed signal.

Let me know if anyone has questions. I hope this inspires some new projects.

V2Rocket

Were these available stateside in the B5 passat?
For most, ordering a transmission from Europe will be a nonstarter.

superman22x

I'm located in Michigan. I ordered my 01E from Germany for 500 Euro (3 day shipping via DHL included in that price). That's why I decided to do all this. It was cheaper than a base turbo transmission, and I ended up with a better matched transmission for my application.

It was never available in the US as a 2wd transmission, only AWD.

V2Rocket

Do you know if that spline adapter would work with a Boxster (012) trans too?
Much wider availability than old 01E.

superman22x

I would assume the boxster uses the same splines as the 944. Seems all Porsche transmissions use a 24t 25mm spline, and the Audi/VW uses a 24t 24mm spline. Either way, the same design could be used if the Boxster had a different spline setup. We would just need a clutch hub from the Boxster. The 012 would not be a beneficial swap for a 944 I think. Similar or worse strength compared to the 016, and similar gear ratios. It would require a more complex gear shift mechanism as well.

KevinGross

Five speed or six speed Boxster? Six speed splines definitely different, five speed I would have to check.

superman22x

If they are different, then the same style conversion would work. Just would get a clutch hub from a Boxster. But at that point, a 968 transmission starts to look affordable...

Droops83

The 5-speed 986 Boxster transaxles are absolute garbage----Spec Boxster guys go through them like socks, and this is with the stock 2.5L Boxster engine! This also means that they are getting really hard to find.

The 6-speed used in the Boxster S is a different trans and should be better, but I am not sure about the torque rating of that one . . . .

Last_Open_Road

Hey - So I am interested in doing this swap as well. I have sourced a 01E Transaxle, and have begun the process of figuring out the coupler adapter. I know Project Nine went through all of this, and I was actually able to get a hold of the machine shop that made his adapter, but they are asking $1,800 for that piece... which I honestly think is insane. The point of this swap was to avoid the high costs, and I know a few people with lathes/mills, so I don't think it would be too difficult. He explained they went through a lot of iterations and I sort of feel that I'm being the scape goat for eating some of those costs. Anyway, I wanted to see how you determined the OAL of that adapter. I'm trying to get my hands on a S4 hub (are all S4 hubs the same? Or would it have to be a B5?), similarly like you did. Did you just cut around that hub and create the outer diameter mounting holes. And when you reference the slip fit tolerance, those are for the holes that would connect to the S4 hub? TIA

superman22x

There is a boss on the clutch hub, that's what centers it. The bolt holes are less critical for alignment. To extract the clutch hub from a clutch disc, you just cut/drill off the rivets, and tap them out with a punch.

I do have a newer design of the adapter, using a 928 flexplate coupling on one end and an audi clutch hub on the other. I can make the adapter piece out of aluminum then. I charge $250 for that piece, and you would have to supply the hub pieces for either end. All the audi hubs are the same I think, but I specifically spec my part for a fixed disc clutch, it's a lot easer to extract the small hub. The sprung clutches have much larger hubs.

As far as Boxster/Cayman transmissions. The 5 speed is an Audi 01X I believe. The 6 speed in the 987 generation is an 0A2, which can be sourced from Europe with nice ratios. It's the predecessor to the 01E.

Last_Open_Road

Thanks! I sent out a feeler to my local VW/Audi group and it looks like someone has a fixed clutch plate laying around of a B5 S4, so I might have lucked out there. I noticed the boss on the picture after I sent the message, that makes sense. It looks like ebay has a good assortment of the 928 flexplate coupler as well. I might contact you up for that adapter piece, making it a lot more reasonable. I've been trying to wrap my head around this swap so I've re-read your and LSA_944's post about 100 times. It doesn't seem too difficult besides the adapter piece, so I'm trying to tackle that first.

Thank you for the quick response.

superman22x

Sounds good! Yeah, outside of the spline adapter, none of the other parts really require precision to make.

Nowanker

Thank you, Superman, for posting!

tempest411

This is a very interesting thread! One option in getting a coupler machined might be to contact a local community college with a machine shop program. A lot of them take on small outside jobs as training for their students, and ask only for a donation to the program in return. The part would be made under the supervision of the teacher, and many of the teachers are very experienced veterans from industry, so you'd be getting a pretty decent part.

Jco3

Hi, I am in Michigan too, and would like to purchase this coupler from you as well.