Gearbox swap exciting project

Right then , I’ve managed to get hold of this 996.2 gearbox very cheap and as the .2 boxes are much stronger than the .1 I’m going to do a manual conversion on a tip . 1 car . So far I haven’t found anything wrong with it in fact it looks lovely inside with no wear on the synchros at all

Perfect timing , we need fresh content and this sounds good..

So youre binning a dildotronic for a manual. I was always told this was frighteningly expensive, but couldn't understand why. Looking forward to watching this play out.

Interested to see how you get in as tip cars are cheaper than manual equivalent. 996 turbo would be a nice conversion

Yep should be a nice project and enjoyable to do , all the parts just bolt on. So i've started collecting everything i need first before i start the swap. i'll maybe fit new diff bearings on this box as well now its in bits fill it with new oil, and give it a good clean up. gearbox mounts and carriers are the same so i don't need those. need manual drive shafts clutch kit/Flywheel slave cylinder/master cylinder/reservoir clutch pedal assembly clutch pipe, hopefully maybe use copper brake pipe. gearshift assembly/ cables i already have a manual instrument cluster i can use. thats about it i think.

Engine wiring loom is different also iirc.

Engine wiring is the same just the vac pipe to the auto box needs closed off, the loom from the gearbox goes to the tcu and can just be disconnected/removed, The wiring from the gearbox multi switch on the side of the box must be altered, 2 of the wires go to the reverse switch on the manual box, park /neutral start wires can be joined or wired to clutch pedal switch. Car will then run and drive, the ECUs are the same with just manual mode selected instead of auto. The .1 cars with the ZF auto are slightly easier to convert from what i've gathered, although info is very sparse If anyone has any other detailed info please post it up.

Great project

Crazy idea to be honest...it'll never work but to help you out of a bad situation I'll pay you double what you payed for the gearbox and save you a load of hassle...what do you think to that? Hey that's what we're here for right? to help each other out.

There’s very little info out there at all for this swap. Keep us posted, Best of luck Hooner.

I didn't think the 996.2 and 96.1 gearboxes were cross-compatible? Certainly the clutch/flywheel assembly is different. Interested to hear if it's doable. The manual conversion really shouldn't be that complicated in the 996.1 the engine ECU is simple enough it shouldn't know there is any difference.

Sponge thought changing the back box on his 964 for a g pipe was a plug and play, no more to pay affair. He managed to turn it into a non runner. Simple is never a word i use when it comes to swapping out bits on cars

Now that sounds like an interesting project and it’ll be good to see how it all goes

they're the same,and the ratio's are the same. Only difference being the .2 boxes have 3 shaft bearings upgraded from 2 and 4 spider gears on the diff instead of 2. to cure the .1 problems. they bolt on exactly the same. either flywheel from 3.4 or 3.6 is fine.

Huh well happy to be corrected. I wish I had known that when I got my .1 box rebuilt!

least of your issues but isnt the instrument cluster needing to be modified as it has the PRNDL indicator?

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Yes but I have a solution for that

This is potentially a very exciting road to travel. Could also end up being the title to an AC/DC song. Good luck Hooner!

While I think of it I’ve got the old manual gear shift assembly from mine if it’s helpful ?

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yes it would be very helpful i have not got one yet. Thanks .

Right I’ve had a good look round inside this box and I think it’s in great shape so I’ve cleaned it out and put the nose cone back on which is easier said than done, note the long stud I put in the casing at the front to help line everything up as it’s lowered down, plus you need to line all the selectors up inside and the shifter mechanism at the same time to get it on. Bit of a pain but it needed to be checked out thoroughly.

The gearbox on my C4S is manual and despite 150k miles it's still fairly clean to shift and no noise in any gear. With all the negative press regarding the engines in these cars it's easy to overlook how good the manual boxes are. A new Sachs clutch and Luk flywheel will complete the joy. Also worth considering is an updated clutch pedal assist spring (only a few pounds) which I find helps driveability.

This is great project. Can't wait to see the progress.

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You have a part number for said spring please

These are from Ashfield Springs and a direct replacement/upgrade to the manual clutch booster spring on my 996.2 The first is a direct swap for the standard spring with equivalent boost. The second is slightly updated and in my view gives a much nicer clutch feel. It's a bit more difficult to wiggle into the plastic booster cannister in situ but works well once securely in place. I've been running the second spring for a year or two and am very happy with it.

Small update on parts arriving, I’ve got a clutch assembly with everything on it, and even a NOS pedal shaft as the auto one is too short but the nuts can be used. Both acquired on eBay

I have to agree how good these gearboxes are although mine was changed by Porsche at about 45k miles at a cost of £7500 .....!!!!!

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bad pinion bearing ? was it a .1 box ?

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No idea, the invoice states " customer complaining of bad gear changes " in 2005 i think. So he paid £7500 for a new gearbox, clutch and flywheel....!!! Yes. 1999 C4 .

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what year was the car?

Er....99.

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opps i forgot

Mine jumps out of 2nd occasionally if I forget to hold it in , I think this winter it'll be coming out and being rebuilt unless Hooner comes to his senses and drops this crazy idea and sells me his "okay" one

I would change the detent spring and put an 8mm ball bearing on top of it and put in some fresh PTX before doing anything else if it is popping out of 2nd.

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It's too good a project i shall see it through , It looks like replacing second gear syncro is'nt to bad to do,it's the pinion bearing thats the problem for DIY as the gears need to be pressed off the shaft. As above try the ball bearing trick in the detent spring 1st it only takes 10mins.

I still fancy an 8/32 Cup final drive, but pretty much everyone I talk to tells me it's a pain on the road, so I haven't pushed it on my build but I'm sure I'm right and it would suit me, I gear all my motorcycles to hit 100(ish)mph and that suits me nicely as well. (it's also what Werks96 do to their cars, but again you can argue their cars aren't aimed at UK roads)

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I was under the impression that caused more problems to the other gears and should be avoided or has there been an improvement ?

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I only know the forum/pub gossip but I would't do it - however I can't argue from an experience point of view, I'm sure plenty have done it. I feel like a bit of a spokesman for Werks96 sometimes but I genuinely have no connection with then other than they're a central point of focus for a lot of people here and I know they refurbish as many gearboxes a year as Hartech do engines and I don't think they're terribly expensive, it's who a lot of people here send them to. They can do ratio changes, pinion gear changes, etc, as well as basic refurbs and their quality reputation is as good as Hartech for engines. They also do a thing that I don't know much about but they hollow out areas to reduce a lot of weight, but you'd need to look into that.

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having seen how this works, i can't see it making any difference (or causing damage)to any other gears, or 2nd gear, all it does is just take out any slack or tiredness in the detent spring which then helps give a little more tightness to help prevent the shifter puck jumping back down the shifter fork,( jumping out) i think it's worth a shot.

I'll take a pic later and show you

The way I see it is the spring just helps keep the selector in one of its 3 positions. I suppose you could just stretch the spring a little to add I bit of lost tension and try it. I have seen others drop a ball bearing in the detent and replace the spring back on top, it may be just enough to stop jump out.

Might be of interest for the nerds

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Exactly this. Porsche will sell you the spring and the 8mm ball bearing too by the way, along with a new detent pin. About £20 for the three. I would not use one of the aftermarket pins.

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How did you replace it in situ?! I can't even take the bloody thing out

Any chance this is possible on a 997.1 do you think? Or is that point too far and they would have too many modules to mess around with compared to the 996

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So it didn't have the 8mm bb from factory? I'll get them ordered..thanks.

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When he uses that 6ft long spanner to tighten up a nut Amazing work He's having a few problems with that spring loaded part ...anyone know what that is?

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No, but I think Porsche realised that as the arm the detent pin slots onto also gets a bit of wear, the BB give the spring a bit more pressure and takes away a bit of play and stops that 2nd gear from popping out. I made a short video showing the play before swapping out the spring detent and adding an 8mm BB. Part numbers in video description.

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clearly not a happy chappy when all the springs fly out everywhere, i can only guess what he says in Japanese

I know them as a ‘pingahf&£kit’ job..

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I don’t know what that is, I need to watch it again. He’s got quite a few good strip rebuild videos. I noticed a while ago hes got an index finger missing!

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It's a tricky but doable job. I moved the drivers seat as far back as possible and with the door open wide I was able to lay backward into the footwell. With a forehead-mounted and other static torches in place I was able to remove the piston and spring from the plastic cannister. You can leave the cannister in situ if you use the standard strength spring. The uprated spring is harder to work into place inside the cannister and to get it to bottom out, so I ended up removing the cannister from the vehicle. For this there is a small circlip that you can ping off (and probably lose!) to slide out the through-pin. It wasn't actually too bad oversll once you have wiggled yourself into place. Despite a new Sachs clutch wirh a smooth bite (fitted by the previous owner) my clutch still felt too heavy. My booster spring came out in three pieces so I replaced it with the standard spring. I still wasn't happy so I fitted the uprated one I list above, and am the result is very satisfactory.

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Are you putting a midweight/lightweight flywheel on it? Looked at different gear ratios but none are made anymore, you can put a 997 transmission in with a few modifications which has slightly sportier ratios and is stronger than the Getrag

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I have tried taking mine out to test the feeling (Americans claim without the spring it's better), and even after watching and reading how I still couldn't do it. In the end I put a pin through the retaining hole to simulate not having a spring and quickly realised it's rubbish. When I had my HU out I accidentally found that the gap in the centre console gives you access to the booster spring as well

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I think it must be possible as there is a kit for sale on ebay with everything needed, plus i have come across a few in the states that have been converted whilst researching about the 996. I'd say converting a 997.1 tip would be easier than a PDK car.

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Re watched video, it’s the synchro hub.

2nd part of build , I don’t waste my evenings

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Yes, about the LWFW, along with an experimental LSD. I was going to put a post up about the ratios and mods yesterday but then deleted it because it's not my IP (or my thread) and it's in the experimental stages with a US company that are making bits to test. I'll post up in my build thread once I've got something to say, but people are starting to take interest in 996/7 modifications that previously they might not have, I think people are realising that the 996 might be the next platform for some special cars.

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I'm tempted to fit a mid weight flywheel /or try and lighten a dual mass flywheel DIY style. i'm trying to find out if anyone has tried doing it. As the crankshaft balances the engine it should be possible to lighten one. I think they sound great.

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Yes! From 14.5Kg in the stock one to 5.8Kg in the aluminium one is too big a jump for me, the 8kg midweight one seems like a great option. I have an aluminium LWFW in the FD2 Type R curtesy of a previous owner, and it is all "go", soon as you step off the throttle there's very little inertia to keep you going. I imagine it's not to everyone's taste when you decide to sell the car as well. But midweights sound like they can definitely enhance how much fun you can have on track and in twisty roads, while not compromising comfort too much. This guy on youtube is a big proponent, maybe you've seen his videos https://www.youtube.com/@DasCayman As to DIY, err it sounds impossible to shave off 6.5Kg safely but what do I know. But if you buy an Aasco midweight flywheel to use as a model to lighten yours, I'll happily take the aasco off your hands afterwards

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I didn't know the 997 box has different (shorter?) ratios, that's really interesting.

Another step forward today as a brake pedal has arrived which completes the pedal assembly now, and a big thanks to Pernickety Bert for sending me his old shifter mechanism and another thanks to 911uk forum for making it possible.

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996: Oil capacity: 2.7L API classification GL5 75/90 Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel Gear Ratios: 1st gear 3.818 2nd gear 2.20 3rd gear 1.516 4th gear 1.216 5th gear 1.024 6th gear 0.841 Final drive 3.444 997: Oil capacity: 2.9L API classification GL4.5 75/90 Mobilube PTX Clutch System: Hydraulically-assisted push-style pressure plate, 240mm unsprung clutch disc, dual-mass flywheel Gear Ratios: 1st Gear: 3.91 2nd Gear: 2.32 3rd Gear: 1.61 4th Gear: 1.28 5th Gear: 1.08 6th Gear: 0.88 Final Drive: 3.44 Courtesy of FCP Euro for those wondering: https://www.fcpeuro.com/blog/the-definitive-guide-to-porsche-996-transmissions https://www.fcpeuro.com/blog/the-definitive-guide-to-porsche-997-transmissions

I got a decent low mileage drive shaft the other day so I’ve cleaned it ready. G/box starting to look better , I still need shifter cables yet and another drive shaft before I start. Getting closer

I see that they are converting a supercharged tip to a manual on the AutoAlex YouTube channel so will be interesting to see how they get on.

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Yes i've been watching that, but their work is way to slap dash for me,butchers they are.

A mate sent me the mechanic bloke they work with doing a 996 ? I wanted to fall on my sword after 4 minutes I dunno how people watch it …

They are quite annoying. Top dead centre are much better less overt bodging

Right then I’ve sorn the car off the rd now as it’s the end of the month, so it begins I have started to drop the engine and box again same as this time last year. The conversion should be easy hopefully. Car raised to the magic number 35 inches from the floor to clear the engine drop.

It’s out again, I’m getting quite quick at this now although it’s still a faff with only a small trolley jack and some blocks of wood. I left the exhaust on this time but it takes up too much space now

Good excuse to give the engine a good clean now too best of luck mate.

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Great photo Hooner. It's given me a better insight on showing the oil pressure switch and wiring along with other components. I plan to change mine during the winter.

Keep up the good work…..looking forward to the end results

Hooner collected his wife early from work on Wednesday, he needed to get home to remove the engine from his Porsche. (Love the trolley jack and wood set up, these blokes with their fancy transmission tables)

Does anyone know if manual engines have this vacuum device at the rear near the bell housing has a port providing vacuum to the tip box, which I can just block if that’s the case.

Nope, well mine didn't anyway

Mine neither

Thanks guys

I'm probably a bit late (if I haven't already posted this, my memory is shot) but MLR are doing exactly this on my build as the donor car was a Tip. If you can get hold of Marc he'd be able to answer anything. If I remember correctly he's putting a C4S gearbox on because it's stronger?? As always it's information overload in there and within minutes I've forgotten 90% of everything but he did explain it all to me. I once tried to explain how an industrial chiller works to our CFO at an event where I drew it on a napkin, after five tries I gave up, it's a bit like that when he's explaining stuff to me

Nice project OP. Great work Regrettably, you don't appear to have a fully equipped workshop : Unlike Uncle Monty who does ... Impact engineering rules. If in doubt, give it clout. And if all else fails, remember there's nothing that brute force and ignorance can't shift Though lord only knows what he's doing with that wood chisel ...

Yes I’m also fitting a .2 gearbox because yes they are stronger c2 and c4s are the same apart from the shaft sticks out the back on the 4s

Time to fit some new parts, I’ve got a new spigot bearing for the flywheel because that’s a good used one but it can have a new bearing, I have a new sachs clutch plate and release bearing plus new flywheel bolts to fasten it on

New rear main seal I fitted last time has held up well no signs of leaking

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Chuck a new release bearing fork pivot in whilst you're in there too.

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Aren't some of the individual gears stronger in the C4 gearbox, 1st gear maybe, because it's 4wd, or have I imaged that?

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Yep I’ve fitted a new one of those, old one here

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I don’t think so. All information I’ve seen says the same .

Job on hold , I need to order a FAG spigot bearing the one I have is rubbish quality, I can’t fit that

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Stronger diff and an additional input shaft bearing on the 996.2 'boxes. Everything else the same in the 996.2 2WD and 4WD 'boxes

Drive shafts being swapped out, manual ones much longer

I love this sort of stuff

Could anyone take a pic of where and which way the clutch master fits under the pedals ,and where the plastic pipe that goes to it routes.

I’ve sorted that now and fitted the pedals, but I’m unsure of how the clutch helper spring works , it looks ok but when the pedal is depressed it stays stuck to the floor, if wondering if it’s because there’s no fluid in the system yet. Any one shed any light on this?

The last pic is the spring, when you’ve fitted it the nail can be removed to release the spring.

Yes when there's no clutch fluid or air in the system the pedal goes to the floor. Well mine does anyway

Being stuck to the floor is normal if it's not fully bled, well mine did that anyway.

Ok i think it's good then they feel right, i must say what a nightmare that job is there's no room to get your arms in at all, it's taken longer to fit the pedals and master cylinder as it did to get the engine out. So next is make up some brake line for the clutch fluid to run to the slave cylinder. I'll fit the gearstick assembly and gear cables then the interior can go back together.

Pedal box area is truly an awful place to work on a car, I always find new ways to curse Well done mate

Bit more done, gear cables and shifter fitted.

I,m on the lookout for a black gear stick if anyone has one. or the horse shoe bit that clips in the centre console .

So the wires going to the multi function switch on the side of the tip box, the 4 wires that are needed are Black/orange Black/blue These two go to the reverse switch on the manual box polarity doesn’t matter. Blue/white strip, Blue/black stripe Wire these two together to start the car. They could go to the clutch pedal switch but I’m not bothered about that. The rest do nothing now. This will only be the case for a 996.1 1999 model without cruise control. 996.2 are totally different. That’s it for wiring

On with fitting the new spigot bearing and new clutch plate , flywheel on and torqued up

Time to fill gear box with new oil and fit new thrust bearing, I little bit of grease on the pivots for the clutch fork, new slave cylinder on as well

gearbox going on so close then DOH school boy error, locating pins in both engine and gearbox bell housing bummer

A derp was bound to happen. Keep going, this is great stuff

Which one is going to be the female? Looking really good Hooner. This is awesome work.

LGbtranaxle talk going on there?

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I've removed the one from the gearbox bell housing , so i'll hopefully get it bolted together now.

Great project. What is the plan for the dials or have I missed that bit please?

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i have a manual set, mentioned previously

Right it’s back together but before I put it back in a remembered i had these new tensioners, so if fitted them while it’s easier access. The old one is covered in wear marks as you can see

I’ve pulled the loom back inside the car now as it’s better than just having it tied up. It’s now back in the loom track under the rear seat with just the reverse wires going back to the gearbox. sorry this is a before pic, the 2 wires now go back though that hole and the bung has been replaced in the hole.

Engine and new box together and in place ready for the reunion with the car

Ok the car starts on the key and is back running again, the reverse lights are working! I'm waiting for a flaring tool to arrive now as the set i have for brakes is not big enough for the new clutch line which is a bigger diameter pipe. DOH!