915 Tranny shift technique? Whats yours?

[Dana_Drury]

Hi gang,

Occasionally I see the inevitable discussing regarding some the 915 transmissions less than fantastic points - i.e. its shifting action. Often I know this is attributed to worn out bushings, or incorrect adjustment, but once you have gone through all those things and gotten the 915 back to as close to good as it can be. What is your shifting technique?

The reason I ask is that I was watching Duke's "Porsche: The legendary cars" DVD and I noticed the footage on the 1970's 911's, and I noticed one of the drivers really driving the gear stick home when changing gears...

I have always been told that you should be slow and deliberate with the 915 transmission (and I still have the occasional trouble of getting it into first gear) but this guy was really giving it some firm action when changing gears.

I guess that speed and ability comes with practice. He didn't seem to be thrashing the car for the sake of it.

[island911]

Assuming the gearbox is in good condition, I've noticed the 915 shifts fast when under load (on it! ) Puttzen around town, you may need to take your time a bit more.
YMMV

[stevej37]

Mine pretty much shifts smoothly either fast or slowly....except for occasionally from first to second. Sometimes need to pause a full second or so before it will enter second gear. I'm not sure why, but I guess I can live with it.

[stuttgart]

I do both .. so it really depends on the type of driving I am doing.. So i vote for (c)


Eric Mckenna
78SC

[Doug E]

Depends on the revs - if high I can be a little quicker but if low then I need to be slow.

[hilandscott]

Breaking in my fresh tranny after the rebuild I came to the same conclusion: slow around town driving means careful and deliberate, but punch it and take the revs up and I can shift much faster and without resistance.

First to second, and occasionally third to fourth still require pausing or a double clutch.

[autobonrun]

Around town, I shift slowly because that's all that's required. On fast runs, I shift quickly with no problems.

The only problem I ever have going into first is at a light after stopping. This problem goes away if you always shift into second then to first. No problem downshifting into first from second with the car moving.

79SC

[glenndeweirdt]

I like to shift slow and smooth below 3500RPM or so, but I still get a lot of gear groaning, above 4000 I am more deliberate with my shifts and the 915 seems to cut me a little slack. Just my two cents worth.

[targa911man]

Mine's sticky from 1-2 at low revs and 2-1 any time. Other than that, it will shift up or down as fast as you want, although I generally don't push it. Fast downshifts are more frequent, and, I think, more critical in terms of the performance and handling of the car.

[JavaBrewer]

I've found that the ligher I am with the shifter the easier it goes. Work/commuting traffic no problems (except the occasional 1-2 balky shift). I experience the most problems when trying to drive fast and find myself jamming on the shifter. Hopefully more experience and a few DE's will teach me to be smooth and "relaxed" with the controls.

As a daily driver I have to say that the 915 is the worst shifting transmission I've ever experienced bar none. Heck my 77 Datsun truck was better than this.

David

[Phoenix]

My only problems are when shifting from 5th to 4th. Sometimes it takes a good 10-15 secs. to get it in. Makes you really plan those passing maneuvers.

[Dana_Drury]

10-15 Seconds!!! Thats a very long time. I might get that shifting from first to second if I am being ultra careful but I find that shifting from 3rd to 4th to 5th sweet as!

[IMONBOOST]

The guy you saw on the legendary video was probably a very experienced driver. To put things in perspective, in the past, the preferred transmission was with no synchromesh. Experinced drivers would shift faster by double declutching and matching revs than by single declutching using a synchromesh transmission. What I am trying to say is that it is not just about clutch down and move gears, but it also has to do with the engine speed and shaft speed and the drivers ability to do this. I do agree that the synchros take long to match when shifting 1-2.

[Kemo]

ive noticed that my 915 shifts alot better when im on the gas up in the higher RPM range. When i say better, I mean I can shift quickly without any balking or grinding. On the other end of the spectrum, I have never been able to get into 1st gear without first going to 2nd. And, I always have this 'resistance' going from 1st to 2nd. If i keep constant pressure on the knob, it eventually slides in. 3rd, 4th and 5th are really nice, and down shifting from 3rd to 2nd is never a problem either. I have a Jacked Up 95' Jeep Wrangler 130K miles and it shifts like a dream compared to my 911. For some reason, I can't help but think that someone would have come up with a fix for these things by now. Maybe the answer is a G50.

[Sean Hamilton]

like rowing a boat, but with a wee pause mid way thru....... after all, she's a lady! deserving of TLC.
If I attempt to hurry her along, she just balks...... hmmm, THAT's familiar!

[NapTownSpeedy]

To put things in perspective, in the past, the preferred transmission was with no synchromesh. Experinced drivers would shift faster by double declutching and matching revs than by single declutching using a synchromesh transmission.

You can really get the feel for this if you know how to drive a Semi Tractor. I drove one for four years and none of them have synchros. By being able to match rpm with transmission speed you then know how to drive.

That said, driving with traffic is deliberatly kind of slow. When I am really on it and going quickly, everthing matches up better and I can shift with some verve.

For all of you making the 3-2 downshift. Use heel toe. No matter what road speed you should not feel the car jerk when you let out on the clutch in 2nd. It should be a smooth transition with the engine now at a much higher rev.

My .02