Danizio

So, I've owned my car for over a year and a half so far and ever since I bought it it's had a chipped 1st gear. I've recently gotten into autocross and it's really been a hindrance grannying it in 1st gear then immediately shifting into 2nd. I'm planning on changing out the clutch over the winter and figured what the hell let's dig myself into a deeper hole and change out this first gear. My only problem is I don't know where to buy a new gear set or just 1st gear in general. Anyone have any experience with this? A link to one would be amazing..

Coopduc

sb3

Have you opened the gearbox up yet? It may just be the syncro/dog teeth on the gears which need replacing.

dporto

These guys may be able to help you... http://www.gboxweb.com/product.html

cds72911

I can't speak from experience, but I am about to do a similar project (I need to go one step further, pulling 2nd gear to replace the 2nd gear synchros). The advice I've gotten (from people much more experienced than me) is that it isn't a huge project if you are mechanically inclined. Drain and drop the transmission, put it up on end, remove the housing retaining bolts, pull off the housing, use a 8" gear puller to pull the gear stack off. Heat the replacement gears and drop them on. I'm sure I've dramatically oversimplified, since I haven't actually done it, but that is the gist of it. The one thing I wonder about (for my job) is whether I need to take off the shift fork by driving out the roll pin before pressing off the gear stack.

GTgears

This is what happens to the gears those guys weld new teeth onto. I would suggest getting a new mainshaft kit, especially if the car is being raced. One can't get 1st gear by itself, so it's a new mainshaft with 1&2. Expect about $2k for the mainshaft and another $1-2k in labor and other needed parts.

GTgears

For a 996 Carrera gearbox a 40 ton press is required to get the gears off. They are press fit, and not splined like the GT3 gears. No 8" puller will get those gears off.

Coopduc

cds72911

I haven't tried it, and you've done lots of them, so I guess that leaves it pretty clear who people should listen to.

That being said, this guy did it with a puller: https://rennlist.com/forums/996-foru...ement-diy.html

GTgears

From his write up...
"This is as far as I was able to break down the transmission myself. Gears 3-6 on this shaft take over 30 T of force to remove, so I brought it to a local automotive machine shop with the new pinion bearing. Although difficult, they were able to press the gears off, replace the bearing, then heat the gears to re shrink onto the counter shaft."

sb3

There is also a special tool needed with the press to remove the dog-teeth correctly, but I have only done this on a 901 and 915 gearbox.

cds72911

Thanks for the clarification.

I thought the OP was trying to get to first (and I'm trying to get to the second gear synchros). If I understood the diagrams, those are on the end that can be pressed off with a puller. No?

Working from the nose/front of the transmission, doesn't it go R, 1, 2, 5, 6, 3, 4? Pulling off the first two gears on the stack would pull R and 1, wouldn't it?

Danizio

Right? I might just go this route if I'm spending $1k-$2k on a main shaft.. That'll save me some headaches!

Porschetech3

That's correct, the "loose" gear R 1 2, and associated syncro's can be removed with an 8" puller
.
The OP has a chipped gear on 1st (large drive teeth) that has probably damaged the "fixed" 1st gear that is part of the input shaft and cannot be removed, the complete input shaft will need to be replaced. To replace the input shaft, the "loose" gears 5-6 3-4 and associated synco's and input bearing will have to be pressed off. While it doesn't require 40 tons to remove these a press is require due to very long reach.

If the "fixed" 5-6 3-4 gears need to come off the output shaft to be replaced OR to get to the pinion output bearing THAT'S where the 40 ton press is needed. Once these gears are pressed off, they go back on with a little less force and can only be removed 4 times as the fit will be too loose. Anytime the gears are pressed off a "R" should be stamped at the serial number indication how many times they have been off.

cds72911