DBJoe996

One will find it very tricky to keep track of all the parts and reassembly. I would check with GBox about a rebuild or a rebuilt unit. http://www.gboxweb.com/

billh1963

Or, you could just buy a rebuilt transmission from GBox with their proprietary upgrades and be done with it.

Imo000

And that`s exactly what you want to do when the economy is collapsing.

Noz1974

Great thanks!

yelcab

At 175,000 miles, the gearbox has lived a good life. It's time for a rebuild.

I agree that the gear set is toast. The pitting is the sure sign. It would be very surprising to me if the second gear is the only one with issues during a rebuild.

DukeTJ8

I agree it’s probably due for a rebuild. I would really like to know more about the 2nd gear pop out. I would hate to rebuild it just to have it still pop out of 2nd. I doubt that it does this from the factory all the way through the warranty period. Does anyone specifically know what causes the pop out to start? Worn synchros, worn gears, detent issues, abusive driving...

cds72911

I hope this isn't too harsh for you, but I'd highly recommend some searching here on Rennlist and reading historical posts, as well as spending a little time with Google. This is not a new issue, and lots of smart people have posted all kinds of great information about the topic that it'd be worthwhile to dig up, rather than trying to rehash it here. Do the research, then ask any unanswered questions.

Here is one particularly informative post from a former Porsche Master Technician that is active on this board: https://rennlist.com/forums/996-foru...l#post15000899

"As for 2nd gear grinding it can occure for two reasons, one being the syncro not letting the slide engage the dog teeth on the loose 2nd gear, or the slide engaged, but then pops out slightly causing the grind.Sometimes it is hard to tell which is happening.

2nd gear gets the most abuse, and the factory admittently got the positioning of the 2nd gear ideal position off by 0.015. The factory fix for pop -out is to adjust the shim stack to move the second gear 0.015 further forward allowing the slide to engage further.

The g-box detent allows further engagement of ALL the gears , but this isn't a problem.

The CMS (California Motorsports) has a modified shift arrester that does the same thing but only to 2nd, 4th, and 6th gear, and requires the rear case to be removed to install.

The loose 2nd gear "dog teeth" are "V" shaped to allow fast and easy engagement. every time a grind occures, the tip of the V is ground or rounded. If too much of the Dog teeth are ground off the slide will no longer stay engaged and/or be very difficult to engage."

DukeTJ8

I have watched about every YouTube video that I could find about this problem. Thanks for the info about Porsche having the second gear out of the correct position. So even if 2nd gear is not in the correct position but everything is new and the synchros/dog teeth aren’t worn the shift sleeve will engage correctly. If the synchros were worn or you have hard shifting into 2nd the dog teeth get ground down and they won’t stay engaged. My plan is to replace 2nd gear, the synchro, and the shift sleeve. At that point I will install the gbox detent to get the shift sleeve to get a better engagement. Please correct me if I’m wrong or you see a problem with my plan. Thanks.

yelcab

I am not a Porsche fan boy, but I find it hard to blame the factory design for something that has gone 175,000 miles before it … pops out.

Imo000

Sounds like a good plan, go for it!

DukeTJ8

I just got the car and it had this problem. I’m not sure when it first started or how it was driven. I’m not knocking the design. I just wanted to figure out what exactly was going on so I could figure out how to fix it.

Imo000

This has been going on for a very long time with this transmission. It didn't just happen 5K miles ago. Most of the time when the first signs of an issue starting to show, the driver will start to adapt their shifting habits to keep the problem from getting worse. They they will start doing other things to drag it on like, change the oil, change the engine and transmission mounts and so on. AND only after all this they will start excepting that this is a problem and just live with it until the car becomes undrivable or they sell it and becomes the next owner's problem. This includes not using 2nd gear at all. Just rev the engine a little higher in 1st and they shift directly into 3rd. You can nurse a transmission with an issue like this for 50K before it becomes undrivabel.

Brian_C

Maybe off topic but I have to share - I had a 05 997S I bought with 20k miles back in 2012 and 2nd gear would pop out occasionally. I recall it was a fairly common issue. Seems Porsche didn’t get around too quickly to address the issue. My .02.