Jeff,

I would look at the thread Randy started a few months ago because he had a similar negative experience that you are going through. If I remember it, he just bought the car and was getting up the gumption to learn to change the oil when the tranny went. The long thread whereby he rebuilt his transmission is one of the best threads on the board. Pictures are excellent and it show this board at its best. After rebulding the 915, I bet he thought changing the oil was not too intimidating.

An Oil Change???? Mere child's play!:D

Doug, I still remember a comment you made while I was doing my rebuild, "Let us have a poll... How many pieces do you think Randy will have left over when he is done putting it back together? Seriously, You got balls Randy, boy!" :eek: Believe it or not, I took those words to heart and double and triple checked all my work and the job came out perrfectly. Thanks!

Getting back to the point, rebuilding really was a lot easier than I would have imagined before attempting it. The guidance and advice given from this board was the key.

Randy

you should never , ever shift in to first while still rolling...

i'm not saying this caused the problem, but it might have contributed... dunno..

but as long as the car is still rolling , even a little bit... don't shift to first, 2nd is the gear to use...

Ingo let his girlfriend drive his 3.6 powered brown turd.....she ummm, FUBAR'd the trans....he rebuilt it in his garage at the condo before he bought his current place. Used his oven to heat up parts for easy slide on....it was fun watching.

The Condo Association wasn't too happy...but what did he care....he was a renter....:D

That is funny and so true. On my 914, I got the engine in and running in a car that I had never driven. Of course, the tranny was bad. I had no idea what it was, so I just took a chance. Pulled the motor and trans back out and went to work on the tranny. Even after only doing a 4 cyl motor, the tranny seemed easy. While I was at it, I installed shorter gears. The 914 901 is very similar to the 915 and there is a real good tech article by Pelican Red Beard on his website. If I had a 915 to rebuild, I would update his article to include any differences.

As far as shifting into 1st when rolling, I do that all the time double clutching. Usually at 5 mph or so. More than that, I just start off in 2nd.

double clutching or not... 1st gear is intended for 0mph only.
it's less important with new gearboxes ( last 15 years )

but on old ones... definately true

Ditto.

That's what the syncronizer is for. Shifting into first while rolling all the time might shorten it's life, but once in a while it's unavoidable.

If the 1st gear synchro is completely shot (like mine was), then shifting into 1st while stopped may not be possible, yes? I found I had best success when I pushed carefully into first while rolling very slowly for the last 10 feet up to the stop. If I waited until the car was fully stopped, I couldn't get into 1st at all, more often than not.

Dan

thanks for all the info guys...

I would love to take you guys up on the idea of rebuilding myself or with help, but I don't have the facility to do it right now in my apartment garage! haha.....nor do I think they would like it that much. I am also just really shaken by this and want to make sure it is taken care of....(also want to drive the car and enjoy it for more than 2 days before I dive into the engine bay.

as for downshifting into first.....the consensus that i'm getting at is to avoid it when possible and if absolutely necessary, double clutch to not wear the syncros. This should be challenging in LA traffic, but hell....makes it more fun IMO.

thanks for reasuring that I'm not a dumbfu@% and that this sortof crap can fall sometimes even with a good PPI and normal driving. I hope to be back on the road soon and maybe show my car to people.....it is so embarrasing to tell everyone who asks "where's the porsche?" that it's in the shop after 2 days.

(oh the sh%& i am taking from the girlfriend on this one!!):mad:

-jeff

Wow that's gotta hurt, having it for only two weeks and all the sudden this pops up. Since it's been rebuilt recently, you might be able to get away with a cheaper than normal partial rebuild. It still seems odd that the syncro failed so soon after a rebuild. Do you know if the first and/or second gear dog teeth were replaced on the rebuild.

FWIW, your car is beautiful. Just remember that it is 25 years old now, and not many 24 year old cars are going to be as reliable as a Porsche.

If you double clutch correctly, it's the same effect as if the car were at a standstill; the relative speed of the gears is the same during engagement .

Synchros are like brake pads. The wear out when used a lot.

Sherwood

actually I got to drive the car not even 3 full days!

yes, I am going to have it opened up and see the full extent of damage and the condition of the other syncros and dogteeth. Might only do 1st and 2nd, most likely 1-4.

-jeff
p.s......yes it sucks bigtime:(

synchro's are not like brake pads
if you shift properly, even without doubleclutching ( which is something mostly you guys in the us seem too focus on ) , your syncro's will NOT be worn every 2 years... in fact , they should last at least 10 years... they are not a wear and tear item ...



one of the reasons for not going into 1st when even doing slow speeds, is the high amount of stress this puts on the tranny , while in 2nd , the amount is a lot less...

1st gear is a high torque , low speed gear, designed only for getting the big lump of metal to overcome zero mph... optimal gears to have the most amount of torque at extremely low speed.. that is what it's for

if your decellerating, and aren't going to compe to a complete stop... you shouldn't go to 1st... you can do it.. but it's not a good thing...

i've never had my synchro's go broken on any of my cars..
clutch.. sure after years and years of abuse.... but i'de rather do a clutch job than a tranny rebuild...

think about what 1st gear does : high torque for starting..
if you do it the oposite, you have lot's of stress , the opposite way... your axles are turning,

unless you can actually match it so it doesn't decellerate beyond where it is.. yep , but you can't, because the rev rage is so narrow, all you can do is pop the clutch and make sure it's accelerating... in which case... why did you go to 1st anyway... 2nd gear is longer , and will give you a better range...

I have been interested in this thread as I want to keep my tranny going for as long as I can. So far it seems fine, but once in a while it's hard to find first. Usually I can feel it go into first, but other times I can't and have to let clutch out a little to make sure it is in gear. Maybe 10% of these it isn't in gear and I wiggle it around in neutral and go back to first and it goes in. I've gotten in the habit of putting it in first while going to a stop with the clutch in. Is this bad? Saves me the worry of whether I will find it when I stop before person behind me gets annoyed. Will be putting new swepco in and new bushings soon which I hope will make finding gears easier. Car drives fine. Also, what is double clutching? Thanks.

I just had my tranny rebuilt about 2 months ago. I had my mech replaced all of the items that can give me trouble in the future. Dogs, syncros, sliders bearnings and etc. It is just a pain to have to go in there again when you try to save a couple hundred bucks now and pay later. No fun to have a breakdrown in the bad areas of LA with a nice Porsche. As for going into first while moving, just to have to match rpm with the gas. It shouldn't hurt anything. No grinding takes place? Anybody like to shed a light on that. Maybe I need to stop doing that. Sometime coming out of a turn is too fast for 1st and too slow for 2nd. What do you guys do? If left on second, doesn't it put too much stress on the motor, "working it". bad for the crank shaft? much more to replace then a tranny?

if your to slow to keep 2nd on ... pop clutch in till you can accelerate again...

now somebody will probably start saying that this will wear out your clutch... but yeah , that's what it's for... in any case, you want your clutch to wear out , not your tranny , not your engine...

that's what a clutch does... it's there to save your engine and tranny from stress...

My definition of double clutching is (correct me if i'm wrong) to up or downshift by depressing clutch once, move to neutral pos. and let clutch out and then press in a second time before selecting the next gear. This syncronizes the gearbox with the engine speed without the use of the syncros in the tranny.

also regarding downshifting into first on the roll.....I always try to coast along in 2nd as long as possible leaving lots of space in front of me to the next car (which is a good idea anyways) and the only time I move into first is on the way to a stop and I only let out the clutch in first when I am at a standstill. So i guess i never truly downshift into first....not sure if that makes sense.

anyways gonna find out when the car might be ready again today....

mostly on downshifting, upshifts don't need it at all
personally i think it's over the top ... the synchro's are there and i use em... i've never had a broken tranny in any of my cars...

hey could someone also explain rev matching and when it is needed? i did a search but didn't find a good definition.

rev matching is the process of blipping the throttle , in the doubleclutching so your engine is up in revs when the lower gear is engaged

again , i use my synchro's for that , also it's a big drag in an early 911 since you need to heel and toe to do that... and the brake pedal on my car is to hard to squeeze it with half my foot on it , and the other half on my gaz pedal...

big discussion on the thread before. search engine will yield enough results on that