915 third gear problem - expert opinion needed (long)

[ischmitz]

I need some expert opinion about my 915/06 third gear problem. A couple of days ago I all of a sudden lost third gear after a friend drove my car briefly. The symptom was that it would not go into third all the way and pop immediately back to Neutral upon releasing the clutch. Gently pushing the gear lever forward to prevent it from popping back to Neutral while releasing the clutch resulted in a horrible grind.

Now that the tranny is out of the car all cleaned up on an engine stand I tried to shift through the gears by pulling and pushing the input shaft. Here is what I found:

The shift pattern seems to be distorted as shown in the right picture. While in the car there was no way to get it into third gear due to the lockout in the shift housing. Now by using the nick to the right in the middle I can get it into third fine.

When I feel around with the input shaft in the neutral position without putting it into any gear I can tell that the initial gates of first and third are really close together as opposed to the gates for second and forth.

My questions are:

- What exactly defines the H pattern inside the tranny? Is it the guide fork?
- What would be my next step considering that I would rather avoid a full tranny rebuild?
- Could it be something as simple as a bad guide fork?
- What exactly can I access by removing the cover plate with the guide fork?
- Could something like a selector fork or something else bolted to the 1st/2nd rod or 3rd/4th rod being out of alignment.


Hope someone can give me some good news short of a full rebuild
Ingo

[surflvr911sc]

Couldn't an F*ed-up or maladjusted shift coupler cause this?

[ischmitz]

That was the first guess, too. But the pattern I am talking abpout is when I push/pull the selector shaft on the tranny out of the car. There is no coupler involved anymore....

Ingo

[ischmitz]

Anyone????

[john walker's workshop]

i don't know about the odd shiftgate thing, but usually when you loose a gear, or it pops right back out, and there's no problem with the linkage, then it's internal, like damaged dog teeth. so finish tearing it down and report what you found.

[POVI]

Hi,

I had a problem similar to yours , where the car wouldnt go into 3rd ..

The problem was there is a couple of sliders guides that look like 3 pointed stars with flat pieces on the end of each leg , that the gear sliders move on.What happend was one of the ends of the 3 stars had broken off .. so that the gear selector could not move the forward enough to engage 3rd gear. if not all 3 ends are in place the slider will not move freely forward and back.

Its easy to find out ...

just unbolt all the bolts on the nose piece , pull that off then
take off the 2 lage nuts and associated gears in front of intermidiate housing then the bolts that hold that on to the rear diff. section and slide the whole intermidiate section forward , and you will have your input and output shafts exposed with all the gears on the shafts.. and you can take a look and see your self .. only takes less than a hr ..

Joe