Is this the way a 915 operates? Or something else?

[Sicklyscott]

Hi -

I've been DD'ing my 1980 911 for the past 2 weeks while my regular car gets repaired. I've been noticing some inconsistancies in the shifting effort of the transmission plus a few grinds here and there. I'm trying to understand if this is just normal 915 operation or if I need to adjust the clutch (or something more serious!).

Here are the symptoms:

- 1st gear can sometimes be very hard to get into. When faced with this problem I usually have to let the clutch out in neutral then push it back down and pop it in first. Sometimes it slides into 1st, sometimes there's still a struggle.

- Downshift from 5th to 4th to pass on the highway always produces a grind but when cruising on the street at low speeds it'll slide in.

- Sometimes 3rd or 2nd will get stuck in gear and take a lot of effort to get the selector out of gear.

I believe there was some trans work on the car in the past with some replaced syncros but i don't remember what the service history said exactly. This car is new to me and it's the only 915 experience I have.

Any help would be appreciated!

-S

[redridge]

sounds like you have a lot of slop on the shifter... I would look at the all the shifter/coupler bushings. Driving a nice 915 is nothing like you describe.

[javadog]

The first thing I would do is adjust the clutch and measure the cable release travel.

JR

[James Brown]

i would start with the shift linkage, make sure all the bushings are in good shape and the coupler has little or no play. Adjust the shifter throw. then check that the clutch is adjusted correctly. If all is good, then yes the transmission might need rebuilding. but the inconsistencies seem to point to linkage slop/adjustments. also, transmission mounts can cause problems shifting.

[Josh D]

Are you clutching all the way to the floor before changes? Are you allowing a slight pause in nuetral when going from one gear to the next? Are these symptoms when trans is cold, or all the time? What kind of RPM do you normally shift?

Before trying to diagnose any trans problem with these cars, make sure all the shifter related bushings are in good shape, clutch cable is adjusted, and shift coupler to trans is adjusted.

Once these are ruled out, then you can start to diagnose problems with the trans.

[yelcab1]

1. Adjust clutch cable travel.
2. Adjust shift rod bushings at the tunnel access port
3. Inspect gear oil for metal pieces
4. Inspect synchros.

In that order ... less to more money ...

[redstack]

Pretty much describes all the symptoms of my new to me 84. I had expected that it was the shift linkage. So thanks for confirming my hopes.
I must say that the 5-4 downshift grind, is the most disconcerting. I sure learned to be very careful on that one.

[wannaporsche]

The upper gear behavior you're experiencing sounds odd to me, but your 1st gear sounds like it works just like mine does:

I don't know if you're moving when shifting into 1st, but in case you are not this info helped me...

I read recently (in a 915 Zimmerman (?) post -- can't find it now) that 1st gear is built to be "downshifted into"-- meaning it works best to engage the gear while you're still moving and the tranny has some spin left that can engage the synchro.

I now find that if I finesse the shifter into 1st as I slow to a stop (traveling at or below 10 MPH) it slides into 1st beautifully every time. 1st does not like it if I come to a full stop in neutral and then once stopped try to shift into 1st gear because the gear is sometimes blocked…which is really frustrating.

My 2c

[Cherry Bomb]

Coupler Whisperer, shift bushings and trans/engine mounts cured 90% of my 915's sloppy performance. I am replacing the clutch cable and related wear items next since the pedal is at the top for action. Also a pedal cluster rebush/restore and...and...and...oops I slipped!

Good luck and have fun doing it!

[porsche moose]

my 911sc did it to went with Coupler Whisperer and trans/engine mounts change trans oil i love kendal 80-90, shifs like butter

[Peter Zimmermann]

First, you should never be in 5th gear at speeds below 60 mph. The 5 to 4 downshift with a grind indicates that you have a linkage problem, either adjustment, or bushing wear, or... If you choose to do this type of work yourself there is much to know/learn, but it can be done. The remainder of your issues can be trans related, or driver technique.

To sort out the technique part always use a two-part shift (the search button is your friend), try to make the majority of your up-shifts between 3500 and 4500 rpm until you start to develop a feel for how the car likes to be driven. Don't do what upsets the car, you must adjust to it; it can't adjust to you. Another poster mentioned that he uses my preferred method of using 1st gear; I always downshift my own 915 into 1st at very low speed, less than 10 mph, and remain in gear while at a stop sign or traffic light.

Getting "stuck" in gear is extremely unusual, and could be oil related. It could also be a problem related to the last trans work. It would be very helpful if you can find your service records so we can see what's been done to the car; i.e. clutch cable replacement, trans oil change/oil type/viscosity/dino or synthetic, etc. It would also help to know if the car has been professionally maintained.

When you drive the car try to not let the revs drop below about 2600-2800, and don't use more than about 4500 for steady speeds. Take your time and learn the car. If it's possible, locate a shop in your area that understands the 911SC, and have their tech drive the car and evaluate it regarding your concerns. And find those service records!

[911pcars]

80% of the 901/915 gearbox issues fall on the previous owner who may not have shifted properly. Porsche synchromesh isn't as durable as in other vehicles/later Porsches. Learning and/or practicing double clutching will extend the remaining synchro life.

Sherwood

[strikee]

I have just replaced my rear shift linkage (eds) / tunnel and cup bushings.

I also replaced the engine and trans mounts.

After an exact adjustment the shifting is much improved.

If you are grinding 5th to 4th you are catching reverse (i think). Again this is an adjustment problem.

I still shift into 1st on the roll up to lights and its slots in nicely.

I am learning to not rush 1st to 2nd but its hard when you are showing off the awesomeness of acceleration.
Ed

[TargaHenry]

I have an 84 with a 915, and I find the above posters to be right on. My car shifts like velvet, and now that I know the car a little better, I know how little accelerator it takes to make the shift perfectly smooth, with a nice earthy power pouring out of each successive gear. Frankly, after the other sticks I have owned, I am surprised by just how smoothly this car shifts.

[Sicklyscott]

Sounds like I'm driving this car all wrong! Many of my up shifts are before 3000 rpms!

During regular driving however it up shifts fine, I do take my time with it and never slam it in.

I'll take a look at my records tonight and report back.

[Sicklyscott]

Ok, here's what I can find/read:

- clutch cable done in 3/2012
- Rennshift purchased in 3/2011
- 1st and 2nd syncros replaced 12/2002
- weltmeister short shift kit installed 12/2002
- clutch replaced 7/2002

What I do not see in all the paperwork is trans fluid replacement, even with all the oil changes. And I don't see anything about bushings.

I can estimate that I 2002 when a lot of the work was done the car had 46k miles on it. It now has 80k miles.

I guess first thing is first, change the trans fluid. While under there ill check for slop in the linkage.

[rbogh901]

Originally Posted by Peter Zimmermann

I always downshift my own 915 into 1st at very low speed, less than 10 mph, and remain in gear while at a stop sign or traffic light.

I find I do this easily and butter smooth just before stopping, like 2mph. The POs of my car probably did not so I prefer to go real easy on the 2-1 shift, no angry shifts are ever likely necessary into first. Once in first and at a complete stop I can easily go into neutral and let the clutch out until time to slip back into gear. As long as the car does not move the transmission will go in and out of gear as many times as necessary and I do not have to keep the clutch depressed through painfully long waits.

[javadog]

Check the clutch adjustment and travel first. Then have a look at all of the shifter bushings, in the tunnel, not under the car. Consider losing the Weltmeister kit. Then you can worry about the trans fluid. It's not the problem.

JR

[boyt911sc]

Originally Posted by Sicklyscott

Sounds like I'm driving this car all wrong! Many of my up shifts are before 3000 rpms!

During regular driving however it up shifts fine, I do take my time with it and never slam it in.

I'll take a look at my records tonight and report back.

Sickly,

A fellow PP member came to visit me requesting assistance for a transmission work because he was having the things you're experiencing with his 915 transmission. He replaced all the linkage bushings and shift coupler to no avail. I took the car for a drive and noticed the difficulties shifting gears and grinding during down shift. Asked him to leave the car and did the following:
1). Re-adjusted the clutch cable travel.
2). Re-align the transmission coupler setting.
3). Drained gear oil and put in Swepco 101.

A week later he came to test drive the car and noticed the big improvement. He thought I replaced the synchros and did some transmission rebuild!!!! Told him just adjustment and maintenance were needed plus learn to drive a Porsche. He was shifting like driving a Honda Civic and advised him to rev much higher to 3000 plus or higher RPM during up shifting and a short pause in between gears.

Tony

[mcfadyenpb]

I would look at the all the shifter/coupler bushings