Tips or tricks for reassembling shift slider operating sleeve assembly?

I’m reassembling my transmission after replacing the 2nd gear synchros, and as expected, the shift slider assembly came apart, leaving me both parts of the slider, three rectangular keys, three springs, and three tiny detent ball bearings. Thankfully none were lost, but I am struggling with reassembly. I can’t get the three spring loaded pieces into place with the ball bearings. Any tips or tricks you could share to help me along? It is super fiddly and frustrating...

Wow... sounds like a real pita. I don�t think there are many here that haveactually had their tranny apart. There was a great thread a few years ago about someone who did their own rebuild. I think you need to find that thread and reach out to it�s author. Good luck and hang in there - you�ll figure it out (hopefully someone with knowledge will chime in).

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Get a tall 13 gallon kitchen garbage bag and/or can and work inside of it so that flying springs and detent ***** are not lost. Then with a large zip-tie around the inner hub load the springs, stones, and *****, then evenly slide into outer slider carefully pushing manily on the stones.. Inner hub orientation is also nessesary.

Thank you. I�m trying that over and over. This is hands down the worst job I�ve ever done as a home mechanic. So incredibly frustrating...

Still open to ideas. I spent the better part of five hours trying, and never got it. Those ***** and springs sure do launch! So frustrating.

So assuming that the picture with the springs and ***** installed is what you should end up with? I.e. pre-disassembly? - Wait EDIT: Can see you've cable tied them in place! I've had similar issues on a much smaller scale with 90's Mercedes window switches ugh anything with a spring and a ball bearing is a complete PITA... Maybe an extra set of hands can help? I.e. 4 people - 3 to do each spring and one to install the casing?

When doing trannys I use the heavy duty fiber wheel bearing grease, if and when they pop out during assembly parts will stick where ever they hit.

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Tighten up the tie-straps as much as possible, use the syncro ring that fits up against the stones to help push them in along with the inner hub, you may have to press in on the ***** a little to get them started going in..You can do it !!! Just takes a little finesse..

Thanks all, I�ll give another go tonight. Thank you for the advice and guidance!

Could a large metal hose clamp be used instead of the zip ties? I'm picturing something like a piston ring compressor setup, you know where you could then gently tap the hub out of the hose clamp and into the slider. Seems like the zip ties are deflecting a bit from the spring pressure.

Good idea. I actually tried a hose clamp yesterday, and it was great for the reason you mention, it didn't deflect and did a better job of compressing the detent ball bearings. Unfortunately, it didn't work well enough. The "stones" (as they are named in the PET - rectangular blocks with a hole in the middle) deflected upward during installation, and it made it hard to access the detent ball bearings, which is key to getting this done. I may have to combine some ideas. The addition of using the synchro as the thing used to evenly push down on it might make all the difference! I may modify the hose clamp with some small drilled holes - smaller than the detent ball so it can't fly out, but large enough to get a small tool (punch with a concave tip?) into. That way, I can get preserve the rigidity of the hose clamp, but still be able to manipulate the detents, as I push down with the synchro cone. I also have a ring compressor that I could try too if the others don't work out. I am not giving up!

Zero experience here but it looks like a fun problem. How about some thin shims between the ***** and the hose clamp to push the ***** more inward? Any chance to install the springs last?

Not sure if there's enough clearance once the two rings mate together but could you use for each block a piece of safety wire or similar, through the middle and over each end or the block, twist the wire to pull it tight?

Success!!! edit: maybe not... I need to look at the manual, but looking at the photos I posted, I may have installed the inner hub backwards. I think those smaller dimples go on the opposite side from the marks on the outer hub. Sigh... I guess the up side is that I’ve done it once, there isn’t any reason I can’t do it again. Thanks to everyone for the support, guidance and advice. I told my kids that my vision of hell would be me forced to try to assemble this thing for eternity. If I never do it again, it will be too soon. What finally worked for me was not very elegant. I held the outside ring in my left hand, with the synchro cone against the left side of the inner sliding hub, with the hub offset to the right so I could load the spring, stone, ball assemblies one at a time (using a large dimpled center punch to push the ball in). I got the first one in, centered it (like it was in Neutral), then carefully pushed it toward the first gear side as far as it could go without launching the parts, all the while I held the synchro cone against the left side to prevent the parts from launching that way. Then I put the second set in, centered it to neutral, then using the synchro cone, pushed it back toward the first gear side as far as it would go without launching bits. Then, holding everything with a vicelike grip in my left hand, I did the same with the third. I carefully pushed all three (of the spring, ball, stone) sets back to the neutral (centered in the groove) position, and quickly had my daughter throw three zip ties on the whole thing to hold it together. I sincerely hope I never have to do this again, and wish anyone else luck if they have to. My best advice is to make sure they don’t ever come apart when you dissasemble the gear stack. Huge props to the pros who do this kind of thing regularly.

Does anyone know if the inner hub is directional? Do the series of small cast in dimples on one side indicate anything meaningful about orientation (like should the small dimples face toward the 1st or 2nd gear side, for example)? The outer sliding sleeve is directional (groove faces toward 1st gear), so it has me wondering. The only manual I have doesn't mention this detail, or any other indicating orientation of the inner hub. On visual inspection, the sides appear symmetrical, I'm not sure about the grooves and teeth since they are no longer visible once installed. There are three sets of multiple dimples in the inner hub. They seem to be oriented 180 degrees from the spring/ball/stone assemblies: And just for the sake of clarity, I am not talking about these (green circled) larger dimples in the outer sleeve. These are marks to indicate where the neutral detents are in the inner circumference of the hub, and are used to orient the spring/ball/stone assemblies.

Well, that's one of the reasons tranny work is expensive to have done! You now have the experience, plus a large chunk of cash in your pocket to show for it...

In case it helps the next person: The turned groove in the shift sleeve (the part that moves) faces the loose gear wheel for 2nd gear. The side of the guide sleeve (the part pressed onto grooves in the shaft) with the large collar also faces the loose gear wheel for 2nd gear.

Sorry, I could have helped you with the orientation of the hub/slider, but I was busy with a family medical emergency.Glad you got it figured out though. Now just methodically reassemble heating the inner races hubs and end bearing to 450f and drop them one at a time onto the shaft, let cool a little then tap with a flat punch to ensure seating. NOTE be careful to locate the syncro rings tabs into the 6 gear slots and the 3 tabs into the recess for stones/ball/spring. The most frustrating part of this operation for me is not assembling the hub/slider ( although at times it is tough) but installing the cover. It has to align with all 4 shift rails and both end bearings also the shift arrestor arm, all before the silicone sets. It hardly ever goes on the first time, and rarely gets done before the silicon sets, meaning cleaning all the silicon off and applying fresh silicon and try again..lol But don't force it !! when it goes, it will drop all the way to the case with no gap..You should shift the trans into reverse to install the cover, and install a longer bolt ect, into the detent hole to hold the shift rail to keep from knocking it out of reverse while trying to install the cover. Hope this helps. Ill try to check back on your progress, your doing good..

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Hope everything's okay Porschetech3!

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Sorry to hear that you had a family emergency. I hope everything works itself out and everyone is okay. Family is the most important thing in the world, we need to take care of them. Thanks for taking the time to send this additional information. It definitely helps me, and will hopefully help others that tackle this job. I wouldn't have braved this job without your encouragement and advice. Thank you! This additional info prepares me for the next fun steps of reassembly. Putting that nosecone on is the next scary bit. I've also been distracted with a bunch of other things and haven't buttoned it up yet. Some reflection: I can see why GTGears recommend having this done by a shop. It is definitely beyond the scope of most DIYers. I've rebuilt engines, rebuilt and regeared transmissions on other cars, and I'd say this is on the more complex end of the spectrum. To do it right, I should continue to strip it down all the way to the case, replace the bearings, evaluate all of the gear health, and reshim the shaft to address the 2nd gear alignment issues Porsche had with these early transmissions. I'm doing a partial job though, since the only issue I've identified is the worn synchro - so I'm taking a calculated risk that it will fix the one issue I've experienced with the g'box. I don't think a good shop would do this kind of half measure work, since they have to stand behind it, so they'd want to make sure it was done right - replacing any potential worn bearings, and refreshing all of the synchros, etc. For me, the only cost of redoing the work is time. If I have other issues, I can always drop the transmission again and do any new/additional work (I have the other benefit of another 996 I can drive when I am working on the other). That additional labor would be prohibitive if you paid for it by the hour at a shop, so between reputational risk, and financial cost, I can see why a shop would want to do it all in the first go. This is definitely doable, but on the higher complexity side of DIY car work - and only time will tell if I am successful. Here's one way to think about it: If you can rebuild your 996 engine in your home workshop, then you can absolutely do this job, no problem. If you can't get your drain plug without stripping it, this is definitely not the job to tackle. If you are somewhere in between, you should take a good inventory of your skills, experience, risk aversion, and tool collection and make an informed decision. Have a great Friday everyone, and best of luck with the family stuff, Porschetech3.

This is a valuable thread. Thank you for sharing, and thanks to contributors.

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Thanks for the kind words and well wishes. My youngest son who is 34yo and has had type 1 Diabetes for 25 years ( diagnosed at 9yo) has had a massive heart attack and was in Hospital for a month and a stent was installed, has been at home for a month and had gotten much better, was able to drive and do pretty much anything he wanted, has had a set-back. The prognosis is not good, but he is getting slightly better every day. He is at home on Hospice Care. He has never been overweight and was a great athlete at all sports as a teenager, and was even ranked nationally 14th in BMX racing at 13yo. But 25 years of Diabetes had weakened his heart even before the heart attack. Diabetes is a terrible disease and can do damage in so many ways even if you consider every calorie you eat, drink, or burn in energy. If you are the praying type, every little bit helps ! Thank you.

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Thanks for sharing Porschetech3 -​​​​​ thoughts and prayers are with you and your family.

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So, the assembly flew apart again (twice!) and I found a better way to get it bak together. My tips for anyone who tries this in the future: I found the easiest way to install the tiny parts was using a cheap plastic ball point pen with a retractable tip. With the pen retracted, the opening was perfect for pressing on the tiny ball bearings to push them into place, and the tip out was great for adjusting the spring location. The second thing that helped was changing the way I was working. Instead of holding the multi-part slider in my hands, I placed it flat on my workbench. This freed up both of my hands to deal with those pesky little parts. The third thing was to have the assembly supported underneath by the 2nd gear, and three part synchro assembly from the 2nd gear side. With second gear flat on the bench, and the second gear synchro parts in place, the back side is both supported and provided a positive stop so the spring/stone/ball didn�t fly out the back side. Once you do this, it limits the number of dimensions you are dealing with and lets you use both hands. With the above setup, I was able to put the slider pieces in place on top, install all three spring/stones, and then one at a time use the tip of the pen to tilt the end of the spring up enough that I could insert the ball into the stone with my other hand. Then, I�d click the pen closed, and with my right hand, use the concave opening in the tip of the pen to press the ball into the hole in the stone and at the same time (with my index finger on my left hand) press the stone in (down) into place until it clicked into the groove inside the slider. Once the ball is in the groove inside the slider it is secure. Do the remaining two spring/stone/ball assemblies the same way. Once they are all in place, they aren�t going anywhere, but as added insurance, put the 1st gear synchro parts on top. Once I figured this out, this became a 10 minute or less job, after spending hours and hours trying different techniques and chasing launched ball bearings and springs around my shop. I wish I�d taken pictures, but it happened so fast once it all came together that I didn�t think to do it. Hopefully this can help the next person. Oh yeah, a toaster oven makes a great small parts heater for reassembly. I got one free from a neighbor who had it collecting dust. Much better than risking the wrath of my wife if I use the house oven... Oh, and a cheap infrared thermometer makes it easy to know when your parts are warm enough to install... If anyone has a blown up transmission and wants to send me these parts, I�ll make a quick video for the community.

Have you given your 2nd gear syncro fix the "all clear" yet? Had a chance for a proper road test yet?

Nope, we STILL have snow on the ground here in Vermont... Soon though! I�ll report back.

Success. IMSB replaced, transmission installed, 100 mile test drive.

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Great job Congratulations !!! Not many have the ***** to tackle this endeavor.....

Thank you for the help, advice, support and encouragement. You are a huge asset to this community, and a helluva nice guy!

Thanks for the write up. I'm in the middle of figuring out how to put those ***** back into their place. Going to try your method in the next few days.

Got the ***** back in their place. Used your method but slightly different tools. Took 4-5 tries before it finally went together without anything popping out. You are right, the last try took 10 minutes. The factory must have some tool to get this done super fast. Thanks for the write up.

There is a comprehensive You Tube video series that shows the rebuild of the transmission. You Tube The 5:25 mark shows how this guy got the ball installed. This should help anyone that is planning to do any internal transmission work.