Rant: I just plain dislike my 915 transmission!

[Poohsan]

If there is one major thing I wish I could change it would be the 915 transmission. I”Ēll even go as far to say that I prefer driving my 914 with a 901 side shift. I just plan dislike my 915. It doesn't like to be rushed, and it is just not smooth going into gear.

This rant is brought to you by the fact that I once again jammed the transmission in reverse. I ran into this problem before my first week owning my SC.
Here”Ēs the link: http://forums.pelicanparts.com/showthread.php?s=&threadid=303567

I know there are gated shifters available but the price is steep. Would it be a crime to put a 901 in to my 1981SC? What are my options? I dig my SC but may eventually move into a newer or older year just to get a different transmission.

Arron

[911pcars]

"I know there are gated shifters available but the price is steep."

What's your definition of steep?

Try Swepco gear lube and adjust the shift linkage. Inspect and replace worn out shift linkage bushings if necessary. Maybe I'm used to my 915. Had a 901 before. I like my current setup.

Sherwood

[Fishcop]

Have a look at the Seine Systems gate shift kit - it adds on to your factory shifter and locks reverse out as well as placing the shifter in the 3-4 plane

http://www.seinesystems.com/GateShift-1.htm

[scottb]

Ummm, it seems to me that a gate shifter will be MUCH less expensive than a 901 transmission.

You're in Westchester, CA. If that's the Westchester down by LAX, there are a bunch of qualified Porsche mechanics in that area. You might consider having one of them do the improvements suggested by Sherwood and then install a Seine Systems shifter, Rennshift or similar assembly. My guess is you'll be much happier, and will have spent less money and effort than would be spent on a 901.

My $.02.

[Joeaksa]

Never had an issue with my 915 and been driving one on and off since 1979....

[ianc]

Everyone will tell you to rebuild it, replace the bushings, adjust the linkage, etc. etc. etc.

But the truth is that at the best of times, the 915 is just an ancient design, and is a balky recalcitrant beast. That's just the way it is.

Either learn to live with it, or look for a G50 car, which is a significant improvement. HTH,

ianc

[Poohsan]

Try Swepco gear lube and adjust the shift linkage. Inspect and replace worn out shift linkage bushings if necessary. Maybe I'm used to my 915. Had a 901 before. I like my current setup.

Sherwood [/B]

After my last round with this problem I replaced the shift lever with an OEM short shift, replaced the bushings, and adjusted the linkage. All of that did improve the shifting. But overall I am just not happy with the feel of the transmission. After I get past a top-end rebuild I'll see if I can dig up some additional funds to go thought the transmission.

Arron

[WolfeMacleod]

I know what you mean. I've owned my car since March 16th, and am still getting used to shifting. It's a very deliberate action.
Clutch
Wait
Out of gear
Neutral Pause
Into gear.

The whole process seems to take about five seconds.

You'd think that they would have put a quick-shifting transmission into a quick accelerating car, woulnd't you?

In contrast, I can whip through the gears in my 924S effortlessly, with 1 second gear changes, maybe two if I'm slow.

[Joe Bob]

If you own a 914 ...then you know what crappy bushings and cruddy oil will do to a trans....mine shifts VERY nicely.

[pwd72s]

Just perhaps your problem is that you've never shifted a GOOD 915...So many of them now have been improperly rebuilt, simply worn out, etc...

[Tim Casey]

my 915 shifts without any incident. Smooth, up and down, never an issue. I like it better than the G50 (personal preference)

[Tsunamiboy]

My 915 trans was completely rebuilt by reputable P-car mechanic and is tight and possative in its shifting.

I added a Rennshifter to my 914 with new bushings and it shifts like new. I thought of putting one in my SC but it shifts just fine so I put the money in bling instead!

[john walker's workshop]

the 914 has the same type of friction syncro system that the 915 does. yours must need work. mine shifts fine.

[304065]

The 915, and the 901, are not "just an ancient design" or a" balky recalcitrant beast." It was designed by engineers from the company with the most significant history of motorsports of the 20th Century. Properly maintained it is more than capable of doing a fine job.

Fix the gearbox, fix your technique, or fix both. The G50 in my '88 Carrera had more in common with the 1980 Toyota SR5 pickup that I learned to drive a stick in (and heel-toe, for that matter, it was a hell of a vehicle) than the 901's in both of my cars.

If you need any further convincing I humbly submit the below video of Walter Rohrl shifting a 901 box. Turn the sound down and enjoy.

http://www.youtube.com/watch?v=U0u_sWeqDwc&mode=related&search=

[dentist90]

Actually I find it shifts pretty good for a 25 yr old design. It is a bit strange having the 1-2 plane not spring loaded, so you have to have more of a feel for where you're putting the lever. Since replacing all the shift bushings and rebuilding the tranny it shifts way better. Worn tranny mounts add to the problem as well.
The only complaint I now have is that the downshift from 5 to 4 can nick reverse, especially with the factory short shift kit. The adjustment for this is very tricky.

[chrisp]

I have a WEVO shifter (but not the linkage or gated shifter in the box) and from what i know my 120k mile box hasn't been opened since it left the factory.

My car is track only and that environment encourages quick shifts. I have no problems shifting my car but I am careful with it. I have never really paused in between gears as you describe.

Sure, you can't do a no-lift-throttle upshift like you can in a Honda or other modern car but it no way do I feel that my 915 box slows me down or that it's balky. I think your box needs to be rebuilt.

Do you know how to heel toe? It's critical on these cars, even on the street.

[scottb]

Originally posted by dentist90
The only complaint I now have is that the downshift from 5 to 4 can nick reverse, especially with the factory short shift kit. The adjustment for this is very tricky.

I had the same problem after I installed the factory short-shift. It takes patience and very small coupler adjustments to get it right, but it can be done.

[DARISC]

I also disliked the 915 when I first drove my SC, "Something's wrong, this ain't right!". Well, fact is, an old Porsche ain't meant for dragging of speed shifting. The 915 is no Muncie rock crusher or Miata slick shifter.

The 915 vsrsus G50 debate goes on and on. Unfortunately, (the opinion of some) converting a 915 to a G50 is possible but not practical. Besides that, the G50, while stonger and more positive in feel (and significantly heavier and more expensive to repair than a 915) can't be shifted any quicker than a properly set up 915 driven by one who's learned to shift it properly.

A correctly functioning 915 trans is not really vague at all. The stick always causes the chosen gear to be engaged at the same position of the stick, each and every time.

True, there is not much tactile guidance offered by the transmission to the hand trying to guide the stick to the correct position where engagement occurs, but that correct position remains always the same, shift after shift. With experience and practice, the driver learns these positions, not by feel, which is admittedly lacking, as just said, but rather by muscle memory, not unlike an accomplished golfer who doesn't consciously think about his every swing but rather lets his muscle memory take over and repeat the same swing every time. When muscle memory takes over, percieved feelings of vagueness in the 915 disappear.

Similarly, for example, a guitarist's or violinist's fingers and hand motions are guided by muscle memory - no gates or guides.

I enjoy shifting my 915 and have come to feel that it has been maligned by those who have driven it briefly and declare it to be a bad piece of machinery but who wouldn't pick up a guitar for the first time and condemn the instrument because they couldn't play it.

Practice makes perfect.

[Tyson Schmidt]

FWIW, it's utterly amazing the transformation in shifting a 915 that comes with a new, properly working, properly adjusted CLUTCH.

[ljowdy]

FWIW, it's utterly amazing the transformation in shifting a 915 that comes with a new, properly working, properly adjusted CLUTCH.

And a new rod, cup and coupler bushing set