Just looking for a little advice on a problem I'm having with my transmission. The set up I have is a 915 tranny with a cable shifter system out of a Boxster. The problem I'm having is that it sometimes pops out of first gear when I start to engage the clutch. And when it happens it is hard to get it into first afterward. And it seems to be getting worse. I'm not sure if it is an adjustment needed because of the cable system or if its something internal. Any suggestions are appreciated.

We'll need images of the underside, rear and closeup of the 915 as well as the path of the cable travel...

Your clutch cable is aligned and tight?

Here are some pics. The clutch is fine. Its like it isn't fully in 1st gear when it pops out. And then there is some grinding when trying to put it in 1st afterward.

Damn, that's a lot of crap to see through - oh, that's the cable keeper;-)

Evil? You're up to bat...

Hard to say with a custom shift setup like this. IF you can completely rule out the shifter stuff, then you are having issues that are consistent with bad 1st gear dog teeth that need to be changed.

Yep...

Disconnect the cables at the tranny and force it into 1st. If it pops out = rebuild... If it doesn't pop out, = cable adjustment...

Um, that will be hard to do. You will likely only pop out under load so someone would have to be back there to put it in gear while it is running, and there is load on the tires

I see what he is trying to say, disconect the shifter and put it in first gear. Then start the car and drive it up the street in first and see if it pops out! Don't need a shifter to do that as long as you don't need to back up!

Worth a try. They usually pop out of gears either that are worn, usually fourth or fifth on a high-mileage car, or when they're not going all the way in to gear. First gears can be worn, but the first thing I'd suspect would be the linkage not letting it fully engage, so it would pop out as soon as there's load. So disconnect it to take the linkage out of the equation, then see where you are, or alternatively lengthen the cable that engages first, so it has a slightly longer throw, see if anything changes. You can do a quick check before driving by disconnecting the cable at the lever that moves the shaft in and out at the transmission, pushing the shaft to put it manually into first, and then comparing that position with where the cable leaves the shaft when it's connected and the shifter's in first.

Just go up hill and it will back up on its own

Is the lash between the clutch actuator lever correctly set (.004in) ? The 915 adjustment is more complicated than the push type clutches.