Time for transmission rebuild? 120k km on the car.

Hello fellow porsche -(wo)men! I have got a 987.1 CS (manual) with 129'000 km on it. I have OEM SSK installed, which, I realize, makes shifting into 1st, 2nd a bit rough when tranny is cold. However, I think my synchro-es need replacement as I am dealing with less than perfect shift action from 1st-to-2nd with grinding noise at times even when tranny is warmed up. So, I am looking to drop the tranny, open it up to see what need attention, possibly only synchro...possibly more parts. I have searched the forum but didnt seem to find any threads on transmission rebuild. The official service manual is very detailed and seem have all of the instructions necessary to do the job. The special tools required for the job does put one off a bit from doing it at home. I though I ask here to see if anyone has taken up on transmission rebuild. How difficult is the job? Is it really necessary given the symptoms I describe above with 120k km covered on the car. Any thoughts highly valued here! Cheerz, KananMR

Time for a rebuild - 2nd gear synchro is a weak item on the tranny and goes out at about your mileage. If it has just started grinding, then you can rebuild. If it's popping out of gear, then it may be too late and better off finding a new trans. Mine got pretty rough so I opted for a low mileage replacement.

My 2008 Cayman S has 83,000 miles on the clock. This about 135,000 km. Mine still shifts well. I think it really depends on how it has been driven over the years. (Most of these weren't by me.) However, I highly commend your courage to open the transmission. I changed my own clutch and many other items. But, opening the tranny would be a bit of a stretch for me. I say go for it. If it's already broken/problem, then what can it hurt. If you do, I would love to see a write up with some close up pictures. I may need them before long. Good luck.

Hi lesmurray - Thank for your thought! Fortunately I've not experienced popping-out of gear yet; only occasional grinding. I guess my utmost motivation for doing this is that every-time I read an "save the manual" type of article on Jalopnik, 90% of the time Porsche manual gearbox is referenced at one of, if not the best. My 2007 cayman is here to stay. I think its going to be one of those situations where I am Mr. Miyagi handing the keys of my old porshce to Daniel-san (my grand kids), if we dont destroy our planet by then I never felt my gearbox shift-action operated anywhere near optimal range. I should have a good reference point; having driven an S2000 for a bit.

Hi RJD - thanks for your reply! Experience wise, I think I am in the same boat with you. I have so far tackled only clutch, RMS, waterpump/themostat, brake job etc. I have a Direct-Oil-Feed kit collecting dust that I plan on installing, which is still nowhere near as complicated as opening the transmission housing. It will be a challenging learning curve, but so was going from oil change to brake pads, then from there o waterpump/thermostat, then to clutch-job/RMS seal/ IMS outer seal removal which involved engine locking. I always work off the official service manual, which when combined with online DIYs and enough time, and a little competency with tools...gives you that feeling that the car is now running just like it should Having said that, my clutch/RMS/ IMS seal replacement kept the car on the jacks for about 7 weeks...which is fine...I consider it... personal unwinding time So, TBH, opening transmission housing does scare the heck out of me!!! considering I only know conceptually what the inside mechanics should be. But, Cayman is now my 3rd car and leaving it on a lift for a few weeks, or even months wont be an issue. If I end up doing the job myself, I will make sure it is well documented here. The service manual will be essential, but I would like to get my hands on some DIY guides as well, before I start. Anyways, thanks for the words of encouragement! If I find some DIYs, I plan starting the job sometime in May/June.

Hello KananMR, Before you try to repair the gearbox, why don't you try flushing the gear oil with fresh ( Porsche OEM) gear oil, also you may want to ensure that the clutch is operating properly, this also means properly bleeding the slave cylinder. Like the saying goes.. 'before having brain surgery, try an aspirin' Good luck!

Along with rebuilding the gearbox another thing to look at are upgrading the shifter and shift cables. The 987 shift cables are a known issue and the factory even sells an upgraded cable set. I have purchased a Numeric Racing shifter and shift cable set. The shifter is a work of art and the cables are very stout. These should give gear changes a much better feel and response.

Kananmr, I have your same viewpoint. I performed the same services to my car, in about the same timeframe. It is a weekend toy for me and time in the garage in just as enjoyable for me as time behind the wheel. I love my car more and more each time I work on it. I don't want a problematic transmission. But, if it happens, I will consider it an opportunity, rather than a burden. When it comes to the Direct Oil Feed for the IMS , I don't know how I feel about that. The kit is not all that cheap. ($800 or so, I think.) Also, LN Engineering recommends just removing the front seal and letting the engine oil lubricate it. From reading, IMS failure on the 987.1 is uncommon (even without removing the front seal). I have seen that oil starvation of rod bearings and cylinder sleeves can and does happen. This usually is to the same cylinders. (I don't remember which one.) This tends to make me think that low/lost oil pressure could be to blame. Scavenging oil pressure from the engine for the IMS worries me.

Hi lesmurray! Thanks for your feedback. The shift cable was replaced about less than a year ago, so good on that front. I have seen alot written on Numeric shifter /cable. Wondering how that would compare to OEM SSK. How would you describe it versus the factory shifter assembly? Is it more of a bolt-rifle-action (like that of S2000 )?

Hi Kananmr, I too have installed the Numeric cables (and their short shifter). I would use that rifle bolt analogy. There is much less overall "slop" in the shift mechanism. I like it. I have experienced a little bit of extra cabin noise which I have been unable to eliminate so that is the trade off (along with the cost). There are a bunch of threads here on eliminating the noise but I have so far been unsuccessful. It doesn't bother me, but I do notice it (at low speeds/rpms and more so with the top up). The sound is hard to describe. Kind of like a vibration noise (guitar string) and I believe it is transmitted from the transmission into the cabin by the "direct connection" of the cables vs. the rubber ended OEM cables which would attenuate a vibration. I would install these again in a minute but best to know what you are in for. The installation was pretty easy. The hardest part is tearing apart the center console without breaking any plastic bits. I have some pictures and found a couple of write ups. If you decided to go down this path, let me know and I can send you pointers.

I have over 140,000 Kilometres on my 06 Boxster S . I have never liked the shifter, stiff when cold especially in first and second and just an overall numb feeling and not what I recall old Porsches feeling like. Porsche really has cheaped out on everything over the years in favour of the mighty dollar!! That said I decided to make some changes and installed all the Function First shifter parts (no more rubber and plastic to numb feel). I also changed the motor mount but was not happy with that, to much vibration and noise.(cant explain the extra engine noise) But the difference in feel and ease of shifting was dramatically better. Although still not as good as the old G50 trannies of days ago. I really enjoy driving a stick again, less chance of missing gears also. The kit wasn't to difficult to install, just need some patience which I have very little! I have read of Boxster /Caymens having cable breaking issues but honestly feel thats partially caused from all the plastic and rubber parts that make it harder to get in and out of gear and prematurely stresses the cables and they break. I find the gears go in and out so much easier .I dont see how the cable could be stressed now. Worth noting is that some people really force the gear changes and I find that a slow steady push is all thats required (its not a slapstick shift kit from 1970) If u want faster shifts buy a PDK car. Its all about the feel of moving the car forward and shifting in the RPM that u like without some Auto tranny doing it all for u. I would never buy a sports car with auto trans.

Having read a little more on this subject, you may find that repair/replacement parts will be hard to find.

have you done the shifter adjustment? mine was a little notchy into 2nd until I did that https://www.youtube.com/watch?v=ZnPmkXDk1r4 Porsche recently released a revised cable for the Boxster and Cayman that changes the routing to prevent the hard curves and breakage issues upgrade to that, no more Noise Vibration Harshness like Numerics and then take out the plasticy junk out of the shift box, many people modify cheap metal Ebay short shift kits and put the factory parts onto that.

I just took a "seminar" on Porsche transmissions through our local PCA club. The shop owner had several open transmissions to show/detail how each part functions. He indicated that the transmissions were actually fairly simple, and that a moderately mechanically skilled owner could do the job with only a few specialty tools. That said, I think his idea of "specialty tools" (having a fully functioning repair shop), might be very different from what the average moderately skilled Porsche owner might have.

I have rebuilt a couple Porsche manual transmissions. It was fun and not too difficult BUT the details are really important. You need to have the proper specialty tools and accurate measuring equipment. Consider your time constraints, budget, and wrenching skills. It may make more sense to pick up a used tranny from a dismantler.

In the US GBox does good rebuilds. I spoke with them before going with a used transmission. Basically, given the miles on my transmission they would have replaced the whole thing with a rebuild and use my case for scrap metal.

Manual transmission are fairly simple. If you want to do it yourself, I think you'll have more difficulty getting replacement parts and having the proper tools for the job. Special gear pullers and stuff like that are needed for that type of job. Other than that, if you are pretty good at wrenching, you ought to be alright.

Hello Kanan, I have the same problem with the secong gear, Where did you find the rebuilt kit?

There is no "rebuild kit" available for these (or any) Porsche transmissions. Porsche does not provide the documentation, service parts, or tools to service or rebuild the Cayman / Boxster G87 six-speed gearboxes. However, a few shops have cracked the code and figured it out. I am rebuilding them with the correct factory tools, parts, and tech doc. You do not want to grind gears when shifting, because replacing the dog rings is not generally an option. They are welded to the gears. The second gear dog ring can be replaced, the others cannot. So I'd recommend servicing your transmission before it goes from bad to worse. Cheers,

I really like the Numeric cables and short shifter effect on how I use the transmission. Now, I routinely downshift into 1st gear. Not so much in stop and go freeway traffic, but when it's warranted for spirited driving. I do double clutch sometimes when the tranny is cold, especially into 1st gear. If you have a LSD , like Wavetrac, then you can really open the envelope of 1st gear use. This allows you to use almost full throttle without wheel spin out of many 15-20 mph corners on back country roads.

Thanks for the info Catellus engineering. Do you know any shop where I can find the second gear parts for fix it??

California Motorsports.

Hi! Believe it or not, either I started shifting better or the problem has been less pronounced since the temps have been warmer during summer cold starts. I think the full or partial rebuild is due with the mileage on the car, but I prolly wont get to it until fall of next year, when I am planning to upgrade my garage to have the space to do it. Meanwhile, I have been taking it easy on 987 until its gets a good refresh of components, and been power sliding on the M3 which is at a less tired condition right now:

Have you tried just replacing the transmission fluid and checking clutch release as previously suggested? Those are both more likely to cause shifting issues than a worn synchro, so you want to eliminate them first.

Did you try and rebuild? Also Can I get a copy of the manual pdf?

Moondog, why don't you first try flushing the transmission oil with fresh OEM fluid..? If you want to rebuild your gearbox you will need a mega ton press plus the special tools to pull the gear cluster apart, depending on where you are I would recommend California Morosports in Lake Havazu Porsche transmissions, parts, service and manufacturing Good luck!

I bought a used Trannie to replace this one and the replacement had the same issue.

Well, on the bright side you won't have to park your car while you overhaul the transmission.. PS: To protect the gearbox during shipment, I bought a large ice chest at Walmart (+/- $50..) and got back safely from CMS