Did my transmission come with a G-Box?

Since I’ve owned my 996.2 for a year now I’ve had it pop out of gear a few times. I ordered a GBox Detent months ago but it hadn’t popped out of gear since about August. Well it popped out again a couple of times yesterday so I decided to finally swap it out today. Does anyone know if the GBox detent looks like the factory detent? Both of mine look earily similar: Is it just the tolerances that are different, or the design? I'm just wondering if I'm going to have a slightly used GBox for sale and a transmission that will need repair soon.

It is visually similar, but the depth from top of the part to the bottom of the roller is longer/deeper on the GBox part. Out of curiosity, was it difficult to remove the plug holding it in? I tried (after removing the bolt that blocks it) and I can�t get that cap to budge. Not a lot of room to work in there. Did you lower or remove the transmission? Any tips or tricks you can share would be greatly appreciated.

Ok, thanks. I�m about to take the car for a test drive. I�ll post some tips (pics of the tools I used) when I get back. You�re right it is tight in there. It took the longest time to figure out how to reach the bolt and plug. Most of it had to be done by feel. I didn�t drop the transmission, but I thought I might have to.

Is it popping out of first or all gears?

Even though you said you got the bolt off, I figured I'd start with that for anyone else who might attempt this job. In order to reach everything you'll need the car up on jack stands and you'll have to remove the right rear wheel. I also removed the plastic undertray(10mm socket and 4mm Hex socket) under the transmission. Forget using pneumatic/electric tools on anything but the lug nuts and the bottom tray, there won't be room to get them in the work area! You can reach the bolt from underneath the car using the 12" (31mm) & 6" (15mm) extensions in the picture below: You'll also need the universal joint and a 13mm socket. You need to come at it from the front of the transmission and the u-joint allows you to reach it at a decent angle. Once it is loosed you can then move to the wheel well. You'll have to get inside the wheel well and go through behind the shock. You can use your fingers to loosen the bolt the rest of the way and remove it. Now you can attack the detent plug. There is no way to get an Allen head (hex) socket in there, so you'll have to use an old fashioned L shaped 8mm hex key. I made a small 8" cheater pipe out of scrap conduit. If you have to buy some conduit or pipe to use, use as small a diameter and you can that will fit over the 8mm hex. I put the cheater pipe over the long parts of the 8mm hex key. I should have made it a little longer, but instead of grabbing another piece and making a longer one I just shoved a screwdriver in the other end and used leverage. Once it breaks loose you can just use the 8mm hex key. I had to do everything left handed, and it was exhausting to turn the plug a few degrees at a time, but I finally got it loose. Then you'll need a magnet tool with a swivel. I HATE this magnet tool, the swivel has NEVER come in handy and has frustrated me. I have several magnetic tools that I much prefer, but today it was the PERFECT magnetic tool! Installation was much easier and I found that I could tighten the bolt by hand and only had to do a quick tightening from underneath. Also I used Redline assembly lube on the detent before dropping it into the hole. Check the GBox installation instructions for the correct orientation. (pin is 90� to the gearbox) I checked that it went into gear before reinstalling the bottom tray and right rear wheel. Then I took the car for a test drive. I really won't know for quite some time if it fixed my issue or not. But I was able to get it into and out of gear, so I'm happy. It's not a hard job, but you finger will be tired afterwards. Shot of most the tools I used. The wrenches wouldn't fit, so leave them in your toolbox.

It only popped out of 2nd gear a couple of times when hot.(During the last 10K miles) But most mornings when the car is still cold I have to make sure it really goes into 2nd the first time or two or else it will grind. I've never had it pop out of any other gear. Car has around 63K miles on it. It was a garage queen with few miles on it until I bought it in Sept 2017.

I've done a GBox swap myself. It ended up not helping so I swapped the transmission for a lower mile used box. Anyway... Your question gave me an excuse to pull the GBox detent from my old transmission and compare them. Both GBox and factory are 4.5cm long top to bottom and same diameter, obviously. The depth, when measured from the roller edge to the wheel, is the difference, the GBox measures 7mm from and the factory measures 6mm. You can see the difference clearly when looking at the wheels, the GBox one is smaller. I attached a couple of photos. To answer cds72911's question... For me, removing the factory detent was a real PITA. It helped to lower the transmission slightly (service manual allows an inch or so). Also, you may have to use a torch to heat up the area around the plug so you can break it free. You might need to modify an 8mm Allen wrench to fit lengthwise. Finally, don't forget to remove the 13mm bolt on the transmission or the plug won't make it all the way out. After the plug is out, you then need a strong magnet (like a rare earth magnet) to pull the detent up and then you will likely need an angle pair of small needle nose pliers to make the final extraction. A mirror can help you see what is going on. Having removed the entire transmission later, I can say it's less work to do it while it's in the car, but in my case it was close. But your mileage may vary, my plug was a bear to get loose. If anyone has a special way to get this done, please share, because it sucked for me. GBox detent on left, factory on right. This was from a 2001 996 Cab (G96 Transmission).

Ah, that's great info. My original detent is slightly over 6mm. I did notice that the GBox detent looked like it had a smaller wheel. Hopefully this solves my issue since it doesn't pop out of gear very often. The only thing is early on cool mornings.

I think my magnet tool is from Harbor Freight...that or it's a Craftsman. It pulled both all the way out.

Thanks! I may have another go at it tomorrow. It�s up on the lift, so I have great access, but there is so little room to work. I popped the bit out of a hex socket, 8mm, I think. I used an 8mm (?) combination wrench over the bit and couldn�t get enough torque in that tight spot. I�ll try a good old fashioned L shaped Allen wrench next time, so I can possibly get a cheater extension on it. It�s a tight spot to try to apply heat, but I suspect that may be the next step.

I didn�t have to use any heat...well none other than the 90�+ garage heat. But I thought I might need to grab my heat gun, and then it broke loose.

Don't hesitate to use a heat gun or a torch. Mine simply would not budge without it. I was using a cutdown 8mm Allen and a cheater pipe kinda like TexSquirrel. I actually called the GBox guys when I was having so much trouble and they put me on to the heat trick.

Oh, and, yes it is a tight spot. I think a torch is best becuase you can put the heat right on the spot better than a heat gun would.

Reviving this for anyone else that takes on the replacement of the detent project while the transmission is in the car. A few tips: 1) Put the car in second gear so that the shift lever (that the shift cables connect to) on the side of the transmission is out of the way. The area you are working in is just fore and a bit above the lever. 2) The bolt that needs to be removed and the "cover" that holds the detent in are both visible from inside the rear passenger side wheel well. Also, I used a 10mm socket, a 6 inch and a 10 inch extension (all 3/8). I suspect that the project would be easier with 1/4" extensions/socket but 3/8th" worked. I did not use a universal joint. A trick I came across was to put the socket on the 6" extension and then from inside the wheel well, position the 6" extension and socket onto the bolt. Then, go under the car and (from the front of the transmission) put the 10" extension onto the 6" extension. Then I put a standard socket wrench onto the end of the 10" (without using a universal joint). I was then able to break the bolt loose and undo it all the way out. 3) make sure you have both a full-size 8mm hex wrench and a "stubby" 8mm hex wrench. I used the full-size wrench to break the cover loose. The stubby was needed to then undo the cover (as the clearance got smaller as the cover bolt came out). 4) I used a magnet on the end of a flexible handle to pull the old detent from down under the cover and a small, bent needle nose pliers to remove the detent. I tried to use a heat gun but I don't think I got much heat on it. The hex wrench set I bought came with an extension handle that let me get good leverage. I'm half way through this but wanted to document it. sjg1138 is online now Report Post

I have to say, I had some doubts as to the GBOX detent fixing the issue of my car slipping out of first gear. Suffice it to say, I am a very happy customer!!! The replacement completely solved the issue. It was, however, one of the most frustrating fixes I've done on this car. Turning a hex wrench a quarter turn at a time combined with the difficulty of getting the hex wrench back into the correct position to start another quarter turn, all while at the maximum extension of an arm was no fun. If you are a bit of a masochist, go ahead with this fix - with the transmission in the car. Anyway, it works!