Shift Coupler Front-to-Back Adjustment
 

1981 911SC
I have the common problem of shifter "hesitation" when going from first to second gear. I recently replaced the shifter bushings with little/no change.

I've done a search, but can't find anything regarding the front-to-back adjustment of the shift coupler (maybe this is my problem?). I did the standard adjustment of turning the coupler one way and the shift linkage the other. However, I notice that there is some front-to-back play in the coupler (when disconnected from the linkage). Is there a preferred starting position front-to-back, before you adjust it by rotataing it relative to the linkage?

Have not done this myself yet, although I have all the parts waiting in the garage. I can tell you that my 915 shifts better than any of the others I drove while looking for my baby. They all (mine included) seemed to 'hesitate' or, better put, required some hesitation between all shifts. This seems to be true of all 915 tannys according to the many threads I have read.

Hope this helps a little.

Eric

There should be no "play" in the coupler in any direction. The fore and aft ajustment is a matter of preference as far as where the shift lever resides in neutral, within limits. It's possible that you could adjust the coupler so that the lever strikes the housing in one direction of the other when the gear is fully engaged. I don't think you want to adjust it quite that far. But, if you're a big person and want the gear pattern a little further forward, you can do that. And vice versa.

Here is the procedure from the tech articles on this site.

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 5th and reverse can be easily engaged. Correct as necessary.

7. Tighten the clamp securely.

8. Shift into 5th 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.

In six step procedure mentioned by Hoss3.0, at step 3, I rotate the coupler CW, but I also have the ability to move it front-to-back about 1/8" or so, before I feel any resistance in the transmission (the start of engaging a gear). I don't know if this is normal or not.

Clockwise would be the correct directiom. Assuming you are looking towards the front of the car.

Using the newer style 914 bushings, this is true. But the original 911 bushings had oblong holes, giving some built in play fore and aft. For my stock '74 shifter, it equated to about 1.5 inches if memory serves me correctly.

To the original poster, I would check to see what bushings you have if you want to remove the back and forth slop/tolerance.

As mentioned, a slight hesitation/balkiness/resistance, going from first to second, seems to be a common trait with the 915. At least mine is that way too.

I'm still not explaining the problem correctly. If I connect the coupler only to the shaft coming out of the transmission (by tightening the set screw), I can grasp the connector and move it slightly front to back (I can also rotate it side to side). Essentially, the shaft coming out of the transmission is what has the front to back play, without changing gears. Obviously, if I move this shaft significantly front to back, I'll change gears. But I can move it alittle without changing gears. Is there an optimum starting position for this front to back play (should I shove it all the way back, or all the way forward, or in the middle?)?

Personally, I like to adjust the coupler with the car in 1st gear with the lever just a "hair" back from the full up-left position. If you go to extreme on the front-back adjustment you run the risk of the linkage binding. This happened to me once, on the road, and freaked me out. I was relieved to find it was only the linkage.

OK, got it. Well, there is always a little play on the sift forks, but they really should be rather close if everything is new. You may have some fork wear, or some slider wear. Both are inside the tranny. You might want to pull the nose off the tranny and check things. Of course, you can't see much from just that, just the intermediate plate, but you can see more than you can right now.

JP911 (Jon) said:
Thanks Jon! Maybe three months ago I had all of my shifter bushings replaced in addition to the shift linkage. Normally I do my own work on the car, no matter what it is, but in this case I didn't feel like spending a bunch of my valuable time doing this job so I had a friend who owns his own shop take care of it for me. He did a good job but I have to say I wasn't totally satified with the adjustment he made to the shift coupler. The transmission was difficult to shift into reverse, the stick vibrated pretty badly in third, there was serious torsional tension when in fifth gear, and fourth gear was a hit or miss situation (usually miss). So today I decided to attempt a readjustment of the coupler myself. After using the Bently Manual's technique, as well as the procedure spelled out in this website's tech section, I was getting nowhere.

Then I tried your technique. I retightened the shift linkage clamp, engaged first gear and then loosened the clamp again. Now the transmission was in first gear. Then I put the stick up in the upper left corner and backed it off just a hair, as you suggested. I tightened the whole thing up again and was blown away by the precision of the shifter. It has never felt this good in my car! The transmision glides smoothly into all five forward gears along with reverse. There's no grinding or hanging up anywhere. The shifter has just the right amount of play in fifth, etc. It's perfect (for an old 915, I mean).

All I can say is thanks for the technique. It worked perfectly and was so easy.

For anyone who comes up on this thread during a search, try Jon's technique. It works.

:D :D

When adjusting via this 1st gear technique, do you put the lever all the way left [i.e., right up against the housing]? I've adjusted mine rather a few times and reverse is still sometimes blocked, so I think I may try again using this technique.

thanx
todd
86 coupe

Yup. After engaging first gear and then loosening the coupler, I went full left on the shifter, right up against the left edge. I held it up against the edge and then went full forward until I felt the shifter hit kind of a rubbery stop. I held it there and then pulled it back just a smidge while watching the coupler slide on the shaft. I let the coupler move just a tiny bit back up the shaft, just enough to feel some of the tension on the shifter ease up. The coupler moved maybe a millimeter. I held it there with one hand on the shifter and used the other hand and a socket wrench wedged in there to retighten the clamp. Maybe you could get someone to do that for you.

I couldn't believe the end result. Perfect.

thinking of trying this method of coupler adjustment to see if 3/4 will be a little easier to get into gear with out trying to get it to shift a few times...

question for anyone.. do you put the car in first and leave it there... then loosen the coupler pin and then keep the car in first gear but hold left and a hair back (while still in first) and tighten the coupler????

in other words I don't ever put the shifter in neutral position right, it will remain in first gear position for the entire adjustment...

thnx

I will try the normal neutral hold left on shifter to stop and rotate the coupler right (or to pass side) and tighten.. making sure the shifter stays right and is in the center of the shift pattern... if it does not help I want to try the first gear method..


Mike

Any thoughts/advice? I am getting ready to give it a go...

"I will try the normal neutral hold left on shifter to stop and rotate the coupler right (or to pass side) and tighten.. making sure the shifter stays right and is in the center of the shift pattern... if it does not help I want to try the first gear method.."

It's not as hard as it sounds. Generally, the coupler will stay oriented to the right and the shifter to the left unless they are moved. I actually sat in the drivers seat and tightened my coupler from that position. Once tight, push the clutch in and shift through the gears slowly. You should be able to engage all the gears. If it feels notchy, try shifting the shifter a little left or right to more easily find the gear. You will see people state that you may need to make minor adjustments if the default procedure doesn't produce the desired result. I actually moved my shifter back very, very slightly to the right for the best overall feel for all gears.

Again, it's not that hard. Just proceed and it should become apparent to you as you are in the midst of the process.

It's not as hard as it sounds. Generally, the coupler will stay oriented to the right and the shifter to the left unless they are moved. I actually sat in the drivers seat and tightened my coupler from that position. Once tight, push the clutch in and shift through the gears slowly. You should be able to engage all the gears. If it feels notchy, try shifting the shifter a little left or right to more easily find the gear. You will see people state that you may need to make minor adjustments if the default procedure doesn't produce the desired result. I actually moved my shifter back very, very slightly to the right for the best overall feel for all gears.

Again, it's not that hard. Just proceed and it should become apparent to you as you are in the midst of the process.

What Greg says is true. Just give it a try. It's quite easy once in there. I was able to position the shifter where it worked best as well by moving it ever so slightly after the initial set up.

I made the adjustment, to be honest I think it was already dead on as far as shifter to the left (1/2) and coupler to the right (pass side)... I may have moved the shifter a bit more to the center to get it vertical but I am sure none the less it has already been done y the shop that rebuilt the transmission... I was just hoping that it would help me not have to fight 3/4th so much but as I understand that is just like that because I need to break it in... only 150 miles since rebuild.... But it was nice to do the adjustment so next time I have an idea of what may need to be done.

thnx guy for your encouragement...