Broken Gearbox

First of all sorry for my English.I have a Cayman s,i bought the car 3 month s ago.My car has 9000km.Yesterday i against with my friends M3 E46 who i won at the past.When i start my car with 2800 rpm,few seconds later when my car had 5500-6000rpm i heard a noise and my gearbox broke!I went direct to the dealer but i will know on Monday which piece broke.I believe that is the differential gear,because i can but all the gears but is like a have neutral! When i start the car with 2800-3000rpm my car jump like crazy for a few metres.Have anybody else the same problem and what i can do for that?Maybe my gearbox broke for that reason because the transmission accepts big forces with the small jumps.I have 19"whells.Please i need help..

I don't know if this is the same issue or not but read: http://www.planet-9.com/showthread.php?t=8181

No,my car has another problem..i can put all the gears but is not moving.

athens - It could be any number of things from a broken differential, snapped CV joints, something internal in the transmission, you name it. Trying to figure something like this out on a Web forum is like trying to diagnose a very sick person over the phone. Take the car into the dealer and have them diagnose and fix the problem. I'm assuming the car is under warranty, I don't understand why you need our help. while we can all feel your pain, in the end there's really nothing anyone on here can do - it's best to have someone who's qualified take a look at it. brad

Perhaps he is looking for help with Cayman drag racing techniques? My advice would be "don't".

I m afraid that all these bounces(jumps of the car at the 0-30km) make deterioration in the parts of the gearbox.I don t know how i can limit these jumps.

No I'm not Santa Fe.I m afraid that maybe is going to happen again,for that reason i wrote all these.Has anyone problem with the gearbox?

The gearboxes are very solid. I would also recommend that you go see your dealer and once they fix your car take a drive with your service manager and show him these "hops" or "jumps" you refer to and ask him how to make it stop and I'm sure he will get rid of the problem one way or another.

I will K-man,thanks.Your car had the same problem?

Athens, haven't seen anything here quite like that. Please do report back when you dealer gets a look at your Cayman. Curious as to what broke and what is causing your "hops". Although I thought I read that you where starting off with 2800 rpms which suggests you are holding the brake and acclerating from a stop. Is that right or am I mis-reading?

No I'm not holding the brake,but I am acclerating from a stop.My car is manual with short shift.

Errr, I guess the "jumps" are rear axel hop. Try accelerating once you're fully in gear.

Like beez said, it's real hard to diagnose something like this on a web forum. And like K-Man S said, the gearboxes are pretty tough. I would venture to say that the weakest link in the power train is probably the clutch. I've blown 7 manual transmissions, so I am pretty familiar with the consequences. The only way you would do this to the transmission is if you 1. Dumped the clutch (and I mean hard, allowing the engine to rev very high and then coming fully off the clutch instantly), 2. Slammed the gears while shifting (again, dropping the clutch very hard between shifts with the engine spinning wildly) 3. By spinning the wheels violently - leading to wheel hop - and then having them catch traction while bouncing. Option 3 would be pretty much impossible unless you disabled PSM. If you do break the transmission, the gear in which you broke it will be missing teeth. It is still possible to drive the car in the OTHER gears, but the broken teeth that are floating around in the oil will keep getting caught in the other spinning gears which will let out incredibly loud and nasty snapping and popping noises. Trying to drive in the broken gear will be nearly impossible and just further destroy the broken gear. There would be no doubt that you broke the transmission and normal operation of the car would be pretty much impossible.

Finally,my differential gear broke.Now I am waiting for a new gearbox from Germany.Another week without my CS!

Wow.... Holy cow.... That's the first I've heard of that. As someone who has broken a few gears in my time (never a differential) I can't even begin to imagine what you were doing to your car when that happened. Care to share?

Nothing,only a fast start with 2.800rpm.Then i heard a strong noise at 45-50km/h and the car stop few metres later.

Maybe it was a defect. Now would be a good time to install a Limited Slip Differential.....

I will next time when i will out of garantee.Now i think because i will speak with my dealer tomorrow the are going to change my gearbox for free.

Sounds like there is a history of fast/hard starts there. Repeated, let’s call it "abuse" for lack of a better word, may be the cause. Does a "fast start" mean revving it up to 2800 and then quickly letting out the clutch while accelerating under full throttle?

You have to do that if you want to start fast.I m not revving up to 4-5000rpm because i know that is dangerous.It is not allowed to break the differential gear with only 2800rpm.I did it less than 20 times in 3 months!

All of that force has to go somewhere. If the tires provide too much traction, then either the differential gear, cv joints, or the clutch is going to take the pain.

I've definitely experienced wheel hop in my CS with PSM on. I've broken a diff in a miata too.

My wheels hop also with PSM off.

I got serious tramp last night. The more I buried it the worse it went, so had no choice but to lift, let it settle then nail it again. Otherwise I’m sure I’d have ripped a driveshaft clean out of the diff.....(It was damp) The Quaife diff should be in the car later this month, so lets see if that solves the problem.

Autocross Start So . . . K-Man you're probably the most experienced with this . . . what's the proper procedure (mucho rapido, minimum abuse) for an autocross start?

The dealer told that our cars have something like a black box with all the driving information like max speed of the car and max rpm for each gear...So'the sent all the information of my car to Germany and they will answer on Monday if the car is in guarantee.My car is only 3 months old!!

Personally, and please don't take this the wrong way, I think you beat the hell out of your car and that's why it broke. However, I also think that Porsche should fix it for free. Common sense here: If you're going to build a $60K+ sports car with 295 hp, 265mm wide rear tires and an open rear end , you better budget for some broken gearboxes due to wheel hop. I don't condone it, but they should expect people to launch these cars hard. Maybe when they get tired of fixing them they will wise up and put an LSD in it.

Gator i did not make anything wrong!Have you ever start a car with 2,800rpm?It is not allow to break the differential gear with only 2'800rpm!I really love my car but i don t want to afraid if i press the accelerator pedal a little more with 1st gear!I paid 100.000euros in Greece for the car=131.000usd!!I have requirements from the car.

I agree. You paid a lot for the car and it is reasonable that you expect to be able to launch it like it's a sports car. Well, I hate to be the one to break this to you, but Porsches simply are not designed for this kind of treatment. I am sort of surprised you got 20 of those starts before it broke. I simply wouldn't do this to my car because I know it can't take it. Porsches have too much traction to start spinning the wheels. When you have that kind of traction, breaking the wheels loose means that the power train must undergo extreme amounts of torque. It can handle the torque. What it can't handle is wild changes in the torque that result from dumping the clutch or wheel hop. Here's what we know: At 2,800 RPM, the Cayman Engine is making ~210 ft.-lbs of torque (310Nm) 1st gear has a ratio of 3.31:1 The differential has a ratio of 3.88:1 So if you dump your clutch at 2,800 RPMs in 1st gear, you are instantly transmitting 2,697 ft.lbs. (3,981 Nm) to the ring gear in the differential (if the tires don't spin). My man, cast iron is only so strong. If you were driving a Mustang, all would be good because that solid rear axle with little weight on it and with slippery tires connected to it (slippery compared to the Cayman's tires) would start spinning long before the torque reached that point. The Cayman on the other hand has it's engine back there pressing down on some of the stickiest tires made by man held my a suspension system that is designed to put the power to the pavement. If the wheels start hopping and biting, you are going from 0 to 2,697 ft.-lbs and back to 0 over and over. My point, if this was my car, and I did launch it like that, as soon as I felt any wheel hop I would let off that throttle.

If this is the case, it often breaks the axle before the diff. I would think that the ringand pinion were not set properly casue the premature failure. If you have a chance, go to take a look at the ring and pinion, look for metal shaving and wear on the ring and pinion. HTH.