Pelican Technical Article: 911 Shifting Improvements

Search our site:

Foreward by Wayne:

Here is some information on improving your shifting and shift linkage in your 911. Thanks to Dennis Kalma and Bob Tindel for donating their tips on adjustment and tweaking.

So for those who have trouble with type 915 transmissions and shifting, based on a broad statistical sample of 1....I conclude the following which is of no validity nor supportability.

Given that the synchro’s are in good shape and they are adjusted right....the suckers are not hard to shift at all. Yes they baulk on forced shifts....but that is what they are supposed to do. If you shift smoothly and crisply there are no problems...no need to run it through other gears at stop lights etc. The key is proper shift linkage adjustment.

So for those who are having problems, here is the "trick"

1. Check the bushings in your shift linkage. This includes the 2 at the coupler between the rear seats, the one under the housing which is in the hoop retained by the 2 smaller bolts on the shift housing and the cup at the bottom of the shift rod. Make sure they are in good shape, they are cheap and easy to replace.

2. Make sure that if you have a later housing, that the longitudinal pivot pin is nicely snug, not too loose. You can tell if you have this housing as it will have a lock nut on the front (visible when you peel back the rubber boot around the shift lever. Consider upgrading to the later (post ‘78) housing and factory short shift kit if you haven’t already.
3. Make sure your clutch is adjusted right. It should engage about � to 1/3 up from the floor board (IMHO) and have about 20mm of free play, measured by pulling the clutch pedal back...as there is a spring which is pressing it towards the floor board, hence the bit of tension.
4. Follow the factory shifter adjustment procedure. It is as follows:
a) Take off the cover between the rear seats which exposes the shift coupler. Pull up the shifter boot, particularly so you can see the lower part of the shifter lever where it bends from "angled back" to more vertical.
b) Loosen the retaining bolt which pinches the shift rod on to the spline on the shift coupler. Let it be very loose.
c) WITH THE TRANSMISSION IN NEUTRAL, rotate the shift coupler clockwise when viewed towards the front of the car. You should be able to feel the coupler rub against the various shift stops as you rotate it back and forth. Rotate it to the furthest clockwise position, as seen when you are facing forward. Don’t pretend you are Tarzan and turn it with huge force....lightly is all that is necessary..
d) Keep your hand on it and hold it there. Don’t let it wiggle, if it does, turn it back to the furthest clockwise position.
e) Move the shift lever so that the more vertical part of the lever is vertical (ie 90 degrees to the level...sticking straight up so to speak). Move it so that it lightly touches the side of the shifter housing which is on the 1^st/2^nd gear side.....closest to the driver. Again, gently.
f) They should now be properly aligned.....lever closest to the driver with bottom part vertical, coupler clockwise in the neutral plane.
g) Carefully tighten the pinch bolt. Make sure it is quite tight.
h) Check things out. You must be able to engage reverse clash free (give the gear a little bit of time to stop after you stomp on the clutch), shifting should get to all the gears easily when driving.....things don’t work as smoothly when stopped and lastly, there must be a little bit of rotational play when 5^th gear is selected. This is checked by shifting into 5^th, and feeling whether you can wiggle the shift coupler with your hand. It should just click back and forth slightly...not much, but clearly discernable play.
i) Assuming all is well, put all the covers back. If it is not well....my fervent suggestion is that you START OVER at b. ....I have never had any luck fiddling with the linkage.

Drive and be happy.

Dennis Kalma
kalmad@cadvision.com
‘75 911S with Kremer 3.2

Shift Linkage - Adjustment

1. Remove the cover plate on the tunnel, behind the front seats.
2. Place gearshift in neutral.
3. Loosen the shift rod clamp. Turn the shift rod (by grasping the coupler) to the right, as seen in the direction of driving.
4. Move gearshift lever to the left until it touches the stop, and move it fore-and-aft until the lower section is vertical when viewed from the side (the fore-and-aft adjustment can be modified to suit the driver, provided sufficient length of the shifter rod remains inside the clamp).
5. Lightly tighten the clamp.
6. Check if equally long travel is evident in gears 1-4, and that 5^th and reverse can be easily engaged. Correct as necessary.
7. Tighten the clamp securely.
8. Shift into 5^th gear, and check the shift rod for rotational play.
A definite (slight) amount of play must be evident.
This is also a good time to inspect the shift coupler bushings. Be aware that some fore-and-aft play in the coupler bushings is required.
Bob Tindel
btindel@gte.net

Comments and Suggestions:

Fsquad	Comments: 82 911 with 140,000 miles. i installed a short shift kit and new bushings in the coupler. With the inspection door open I hear a noise like a throw out bearing on a standard trans that I do not hear with the door closed. Bad things on the way? Thanks, Tom
July 1, 2011

mnwgilbert	Comments: I have a 1985 911 Carerra - when I shift from 4th to 5th gear, I am shifting in the same spot as always, but now it goes into 3rd gear instead of 5th. I have to really thread it through a narrow path right to get into 5th. Any quick fix suggestions?
June 22, 2011

Gary	Comments: Shifting can be hard going into 1st and 3rd. Sometime I have to double clutch first. Is this a linkage problem?
December 28, 2010
	Followup from the Pelican Staff: I typically like to start with the things that are easiest to fix. In this case, yes, that would be shift linkage. Go through the linkage and replace all of the bushings that may be worn, including the coupler underneath the car in front of the rear seats. Then, you can accurately evaluate the shifting, and focus on the transmission if the problem still persists. - Wayne at Pelican Parts

Gary	Comments: What type of oil do you recommend for an 85" carrera 3.2L with 132,000 miles? Should I use a synthetic?
December 28, 2010
	Followup from the Pelican Staff: This is an age-old question. I like to recommend not using synthetic in older cars, as it tends to increase the chances that the car will start leaking oil. If you try to switch back from synthetic after a leak has begun, then it tends to continue to leak. I like running heavier oils in the summer, and lighter-weight formulas in the winter. Recently, the oil formulations were changed and a lot of zinc has been removed from the oil (due to the theory that the zinc residue in the exhaust was harming and shortening the life of the catalytic converter). As a result, the absence of zinc (which is an anti-wear component) has been causing more wear in these cars. So, I recommend either adding a zinc-based additive, or use an older formulated oil. - Wayne at Pelican Parts

jr	Comments: I will give that a shot and with any luck that will be all that needs to be done. When I have repaired that I have a few driveability questions I think I got my hand spanked on this purchase
September 18, 2010

jr	Comments: Hello I have a 1986 930 and it's my first porsche. The vehicle is equipped with a 4 speed and I can not for the life of me get it to go in reverse no matter what I do HELP ?
September 17, 2010
	Followup from the Pelican Staff: There's a lockout mechanism on the shifter that may be stuck. I would pull up the boot and take a closer look at it as you try to shift between the gears. - Wayne at Pelican Parts

Pmancat	Comments: I have an 87 turbo-look cab that has a problem when the car has been driven in heavy traffic. The clutch seems to disengage and once it cools it engages as if there is nothing wrong until it heats up again. The clutch has been recently replaced and has had a major tuneup. Any suggestions as to what may be causing this? Thanks, Raul
August 28, 2010
	Followup from the Pelican Staff: This is somewhat standard behavior for a clutch that is getting hot and overheated. I would hazard to guess that you're probably riding your clutch a bit too much in traffic and need to use the clutch a bit less? - Wayne at Pelican Parts

W Bergman	Comments: I applied Bob Tindel's procedure for "911 Shifting Improvements" and now suspect it was written for later post '71 911's? Step 3 & 4 "turn the shift rod to the right," which moves the gearshift lever to the left, before tightening the clamp under the tunnel cover plate in the rear. My 1st and reverse now could not be engaged. The solution was reverse things: turn the shift rod to the LEFT, and thus the gearshift lever to the RIGHT before tightening the clamp. Now all gears engage, and a test drive confirmed the adjustment.
May 17, 2010
	Followup from the Pelican Staff: That's correct, on the early 901 cars, the shift pattern is different than the 915s, so the procedure would be backwards. Thanks for the helpful followup! - Wayne at Pelican Parts

Dabo	Comments: How do I get new bushings in the shift coupler? It looks like its molded together.
May 9, 2010
	Followup from the Pelican Staff: The pin on the inside is pressed in to the coupler. This is documented in the 101 Projects book. - Wayne at Pelican Parts

Jef	Comments: Eureka, made up one out of a wall fitting for a cloth hanging bar. Fitted it to a drill are ground it down to fit the shift rod bracket. The material revealing itself as brass or bronze, i cant tell. Has about 2-3mm clearance total. The longer construction gave it more stability. Better shifting consistency finally.
November 1, 2009

Jef	Comments: The Shift Rod Bushing in the Tunnel Behind the Shifter fails easiest in my car. 4 years after replacement, and it has gone to bits. Hardened and brittle. Wondering if a bronze or other metal type would be better.
October 27, 2009
	Followup from the Pelican Staff: I've tried bronze ones before - I don't like them too much, as they have looser clearances than the rubber / plastic ones. Be sure that you install the bushing with some white lithium grease, and it should last a bit longer. - Wayne at Pelican Parts

geigez	Comments: Wayne, my guess is the coupler would be the same I just wanted to know if there was a chance it could be the wrong part. It's a RUF transmission in this 930 but from the shifter to the back plate I'm guessing it's the same. thanks much
September 15, 2009

Geigez	Comments: I have a 5 speed RUF. Reverse on the left up position. My nylon bushing is shot and need to be replaced can't get Reverse or 1st does this method still apply? where can I view a diagram for replacing the bushings under the plate?
September 14, 2009
	Followup from the Pelican Staff: I'm not familiar with that particular car and whether or not it has a stock shifter? - Wayne at Pelican Parts

Search our site:

Guest Technical Article:

911 Shifting Improvements