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996 Tiptronic to manual transmission swap - 2004 996.2 Carrera 4S with A9635
Disclaimer: "You may be an ape with a wrench. It's possible you should never be in the same garage as a car when you're holding a wrench. Therefore - what I am writing about hereafter describes what I did – and suggest you use as a reference but not a stand-alone. If you break it, bend it, pork it up, kill yourself doing it - I never told you to do it. I just told you how I did it. You're an adult - own up if you screw up. Check to make sure what fits yours as they can be (and are) different.
P.S. Disclaimer: I didn’t mind the Tiptronic transmission at all. I thoroughly enjoyed testing the cars limits on the Tail of the Dragon and Cherohala Skyway by shifting with my thumbs. I wear size 14 construction boots and drive in the city quite a bit so I’ll probably miss the Tiptronic at times. A big part of me doing this swap was I needed a project and well, why not....?
But seriously, this is not a bad job at all, it’s just there’s just no information out there about it. I bit the bullet and it worked out. Nothing to fear; no tolerances, clearances, etc. to verify and the bolt in part is straight forward. All the parts I used bolted right in. Get the car up in the air, put jack stands under it, and get to work! This was a very gratifying project. Fun to do and not scary once started.
Obviously there is a cost to do this but if you’re lucky, some of it could be offset by selling your old transmission and associated parts. Is it easier to sell the Tiptronic and “just buy a manual” like the internet says? That’s your debate but if you’re like me and love your 996 and plan to keep it....then it’s probably not really an option. My labor was free, so no idea how much it would cost to do in labor.
First thing – don’t let the internet intimidate you....this is NOT hard and the wiring is NOT impossible or a nightmare like everyone claims. The car does not need to be torn apart and rewired. I suppose it’s the same drama stirrers that claim imminent explosion of your IMS bearing if you breathe too loud, or immediate bore scoring if you don’t drive the car for a week that, insist what they haven’t done is not possible to do. This transmission swap can easily be done on jack stands as that is what I used to drop the engine/Tiptronic when I built the 4 liter (again, another “impossible” job to do at home... but I digress). However, between the two projects I was fortunate enough to have bought a 4-post lift, which is just plain awesome. Do your research on these though to make sure there is enough room between the runners to drop the engine between.
Online parts diagrams, the forums, social media groups, eBay for photos (and pricing) are your friends. Gather all of the parts you’ll need beforehand and do you research. There isn’t much info out there on this swap (yet) but hopefully that will change. I’m certainly not the first to do it but hopefully a quick write up will encourage others. I managed to get a few bits and pieces of information from across the globe and from some awesome, knowledgeable people. If you added input, advised, suggested, or helped support this project in anyway, I thank you.
Major parts swapped out:
Transmission: my car is all wheel drive, so I sourced a G96.31 from a wrecked 2003 C4S with almost identical miles that I have on mine. Spacer ring for the Tiptronic transmission was not reused. Flywheel and torque converter also removed.
Axles: The axles are considerably different lengths. The Tiptronic axles are shorter and had a spacer ring in them. Same nuts and bolts to secure them on both ends. Nuts have an immense amount of torque on them, 340 ft-lbs. I ended up buying a ¾” breaker bar, various extensions and socket set to get them off. Used my body weight and length calculation to get them torqued back to spec.
Upper transmission carrier: this attaches to the underside of the car in a slightly different location than the Tiptronic support bracing does. The threaded holes were already in my car, used same bolts.
Lower transmission carrier: this is different between the Tiptronic and manual. Uses same mounting studs and nuts. Pic below shows upper carrier attached to lower carrier
Under transmission chassis cross brace: this is slightly different, but I don’t think a change out is truly required. Same bolts.
Console shifter mechanism: obviously the manual gear selector swaps in place of the Tiptronic. This console is held in place by (4) 10mm nuts.
Shifter cables: (2) cables for the manual versus the (1) for the Tiptronic. Remove the emergency brake handle and work the rubber bushing out. Pull the old cable out from underneath the car, pull the manual cables up from below. A little grease will help the bushing move in place, it’s tight!
Hydraulic fluid reservoir: the existing reservoir had the clutch nipple but needed to be opened and then I’d have to source the line locking mechanism for the clutch line. I just bought a new manual reservoir ready to go.
Clutch master cylinder: Bolts directly to the under-dash frame/support, already in the car.
Clutch slave cylinder: obviously need this on the transmission.
Hydraulic clutch lines: The clutch line brackets are already in the car, just remove the under-body splash shields and look where the existing lines snap into their holders. The hole in the firewall is already there to pass the hydraulic line from the clutch master to the fluid reservoir. I just put a hole in the (2) existing grommets and reused.
Clutch/brake pedal assembly: the manual rod is longer as it needs to hold the clutch pedal. It also has a support cage that gets bolted to the side of the steering column. I was able to move the relay block out of the way in the footwell and slide the old rod out and new (longer) rod in and swap everything from under the dash. Contrary to popular belief, the dash does NOT need to come out. I did need to temporarily remove a piece of the HVAC ducting. I also left out the clutch helper spring, clutch feels fine.
Metal and rubber cooling pipes: there are (2) metal lines and and a few rubber lines that I swapped out. The cooling lines come down the left side of the Tiptronic but are on the opposite side for the manual transmission. You could possibly use the Tiptronic lines but I don’t know.
Items reused:
Center console and all of its “bits”: the manual shifter boot ring snaps in the same way the Tiptronic lever surround does.
Gas pedal: only difference I can think of is the kick down switch but that’s no longer active and the wiring is left in place in the harness.
Front cardan shaft and guibo (aka flex coupler, donut, flex disk): I was able to use the existing for both transmissions.
Front differential: I was able to use the same unit for both transmissions.
Grommets and brackets: all body grommets and under car brackets to hold the clutch line.
Dual mass flywheel: the one I got with the transmission was well within tolerances and looked to be a recently replaced unit. Not cheap so I used what came with the transmission.
Transmission shift control cable: this runs from the ignition to the Tiptronic console shifter. I don’t fully understand how it worked but haven’t investigated it. Its tucked tightly under the carpet and does nothing now. I imagine it worked in conjunction with the P/N interlock and ignition switch?
Nitpicky bits that I bought new:
The correct coolant pipe plastic support brackets
one rubber clutch line bracket
foam pads (stops) at the rubber transmission mount
new clutch disc and kit with new flywheel bolts, pivot, fork, spring, sleeve, etc.
New brake light switch, clutch switch, and starter enable switch.
New male connector for the transmission reverse light switch.
Replaced the Tiptronic gauge face with a manual gauge face
Wiring
I left every bit of the Tiptronic harness in the car.....won’t see it and at most it weighs 2lb’s. The section of wiring that goes through the body and plugs into the actual transmission was pulled back and secured inside the car. I removed the gear selector and steering wheel control boxes from under the console (attached to the gear selector). I had originally left them all in connected and tucked nicely under the console but somebody wanted them and the Transmission Control Unit as well, so they got removed.
parts removed:
I only needed to make 3 new wiring harness sections.
1) a harness from the reverse light switch on the manual transmission to the existing Tiptronic shifter plug under the console. I connected to the same wiring harness that plugged into the Tiptronic gear selector switch (connector for pins A1 and A2).
2) a harness to incorporate the starter enable switch that is fed back to the dme. This is the microswitch that is activated once the clutch is fully pressed and allows the starter to engage (pin D1 on the dme).
3) a harness to incorporate the cruise control shut off action when the clutch is pressed. This feeds in to the back of the cluster (pin C19 on the cluster).
Bolt everything in and run those wires and your car should start, run and drive! You’ll get a Tiptronic Emergency Run error message in bright red but it will run. Some people have mentioned the need to rewire the start relay but I did not need to do anything to it.
The last bit is the fun part – programming through PIWIS. I’m still playing about (i.e. learning) with my PIWIS II tester but have managed to activate the clutch switch and moved the PSM system over to the manual transmission setup. I have not fully coded the dme over to the “manual” transmission program yet, so it’s still looking for the Tiptronic and has the error message. Still learning that piece, ipas codes from Porsche are required....
I removed the driver’s seat to do all the work. It made life way easier getting in/out of the back (not to mention leg room!!) and lying flat on my back to do the under-dash wire feeds and pedal swap wasn’t bad. The rear parcel shelf needs to come out to get to the main dme and the passenger rear side trim and door sill needs to come out to remove the TCU, if you so desire. All new wiring is labeled, hidden and follows the same path as the existing harness. Only one wire is routed under the carpet (from the clutch to the main dme).
I have a TON of photos to add so ask away. I'll add part numbers to this post as well, I want this to be a positive resource thread. If you have items to add that will help, please do!!
I've also added .pdf of the bits and pieces of the wiring diagrams of my car and how I sussed them out. I like colors and snippets as you can tell. Again, this is how it worked out for my 2004 C4S. Check the wiring diagrams for your year.
Now, on to the last 5%... if anyone can help me finish the programming through my PIWIS interface and software, I'll be glad to take the help!!
I am doing this, too, to my 996 Turbo. I am in agreement with everything that you have written. I have some notes that won't help you, but may help others.
1) The Tip you have is the Mercedes 722.6 which is also used in the 996 Turbo. The tip front mounts are the same as the 996 Turbo. I believe the earlier ZF Tip uses the same front mounts as the regular G96 gearbox.
2) The cable from the ignition lock locks the shifter in park when the key is removed, and prevents the key from being removed unless the shifter is in park. I think it's safe to just tuck it out of the way, remembering that the free end moves in and out.
3) The 996 Turbo uses a separate fluid tank for the clutch system - the clutch master isn't connected to the brake fluid tank. That might be an easier way to go if one doesn't want to mess with the brake master cylinder tank.
4) I believe the Tiptronic warning is originating from the cluster, not the DME. I believe that warning is because the cluster expects to have the Tiptronic shift position switch connected and it isn't any longer. I can do some checking over the next few days to confirm or deny this, as I still have the complete Tip installed.
5) I have been told that, at least on the 996 Turbo, you cannot code the cluster or DME for Auto or Manual. It is possible to reflash the DME, and supposedly possible to reflash the Cluster, to Manual. This might be possible through PIWIS if you have the correct IPAS codes. I was also told that anyone who produces tunes for the car can reflash the DME from Auto to Manual without too much trouble. This was my experience with some VW Auto to Manual swaps on VW's with the Motronic 7.2 system - ECU cannot be coded for transmission type, even though there is a selection in VAGCOM for Auto/Manual it does not change everything.
6) The Tip metal heater pipes are the same as the 996 Turbo, so I only had to buy some hoses for my swap.
7) Be careful of the large coolant hose that has the Tip coolant line coming out of it. It may be superseeded to a 997 part, and the 997 hose is about 1 inch longer than the 996 hose. This caused a kink in the hose on my car and seriously blocked coolant flow to the radiators. I ended up trimming the 997 hose to match the 996 hose I took out. It's possible this is specific to the 996 Turbo and won't be an issue for you.
8) I like your garage floor and wish I had as much open space in my place.
Last edited by theprf; 04-29-2022 at 11:22 AM.
Reason: More notes
Excellent write up! Seems like this post was half the effort. Enjoyed reading very much.
Originally Posted by e30rapidic
A big part of me doing this swap was I needed a project and well, why not....?
May I PM you my full address? I have projects!
Originally Posted by e30rapidic
I suppose it’s the same drama stirrers that claim imminent explosion of your IMS bearing if you breathe too loud, or immediate bore scoring if you don’t drive the car for a week that,
sooooooo a HUGE thanks to @Mpfaff is in order for this one.
He sent me a cluster from a manual C4 and voila, no more "tiptronic emergency run" error message. After about 30 seconds, that gas gauge started to rise as well.
Went for a quick ride and it was so nice to feel the engine at full song again. I'll drive it around as is for a few days to make sure...but I don't expect that the fault will come back after that drive. Fingers crossed.
New cluster has the navigation module in it, so it's looking for the PCM. Hence the 9114 code. I'll sort that out at a later date but for now I'm not going to mess with it....
So for now, my concensus is that you need a manual cluster to do this swap. PIWIS I nor PIWIS II could code the tiptronic out from my original cluster.
Wow, that .PDF is pure gold!
I assume the PIWIS has the entire wiring diagram.
Wish I could pickup a used PIWIS.
Good!!! I put a load of work into that .pdf so hopefully it will help others. I found the wiring diagram on the web and just studied it and researched. Combined the eco pinout diagram, etc. Bit of trial and error too
If hypothetically, I had a 01 tip car with a bad engine and a 99 manual car with a good engine, and wanted to swap over the engine and all the manual bits to the newer tip car, is there any reason not to just transfer over the DME along with everything else? Any headaches come to mind with that approach?
If hypothetically, I had a 01 tip car with a bad engine and a 99 manual car with a good engine, and wanted to swap over the engine and all the manual bits to the newer tip car, is there any reason not to just transfer over the DME along with everything else? Any headaches come to mind with that approach?
u have to swap imobilizer and key fobs and it will wok fine. I did this with my gt3 swap. U will also want to swap the cluster.
04-29-2022, 12:29 AM
996 Tiptronic to manual transmission swap - 2004 996.2 Carrera 4S with A9635
