930 transmission overhaul

[diabolos88]

Aseem whats the status on your rebuild? your thread is tempting me with inspiration to try doing mine also.

[briankeithsmith]

OK, I'm tearing down my tranny today. I'm to the point where I need to remove the selector fork(s). I assume just unbolt those, and slid them off the shaft to continue disassembly?

If so, is there any reason at all to remove the selector fork shafts? I can't really see any reason to remove them, but figured I'd post the question to confirm.

Brian

[aseem]

Brian. I think the best thing is to first remove, what i believe is called the detents, seen on this picture. This way you can remove the selector fork shaft and the fork in one piece. The hole assembly can be slid off together with the shift slider.



If you take the fork off the shaft, you have to adjust the forks using a special Porsche tool (expensive). I disassebled the fork, and had to re-adjust without the tool

[briankeithsmith]

Yeah I had done all of that.

It ended up that it wasn't in neutral so I couldn't get them out.

I got it.

Brian

[aseem]

Time for an update.....

This has taken a lot longer than I expected. Mostly due to my job requiring too much attention. But finally, the case was back together and bolted to the engine a few days ago.

Thanks to David (dyerkes) I managed to separate the dogs from the gears. David send me his tools from the US to Norway , so that I could separate the dogs. I really tried to separate them without the tools, but it got me nowhere. David and I had only emailed a few times before he suggested he could lend me his tools. Thats what this forum does; bring trust and friendship among men otherwise stangers. Thank you David!!!!

I have replaced all the syncro rings of course, and also 2nd and 3rd dogteeth. The slider for 3-4th gear was also replaced, although strictly not neccessary.

When reassembling the dogs and gears, I left the gear in the freezer over night, and heated the dogs in the oven to about 150 degrees C (300 F). I then used the bench vise to press them together, but a press would have been better. Here is the completed 2nd gear:




Stacking the gears back up is quick, so cuick in fact that I forgot to mounty the shift fork and rod together with its gears (the rod and fork can not be mounted AFTER the axle has been stacked with gears). So I had to disassemble again, so that I could mount the shift fork and rod unit. Each time the end bearing was heated to about 150C/300F degrees, and slid right on the axis

I must have done something wrong this second time, because when I torqued the intermediate housing, the gears would not rotate. Opening the housing nuts, and the box is rotating again. I had to pull off the bearings for the second time during assembly, and redo the stack. I don't know what I did wrong, but I made shure to stack the grears correctly. Finally the gear stack is all right, as seen here:




The needle bearings shoul really be mounted the same direction as before dismounting, so marking the bearings is a good idea. The gear pairs (fixed and free gears) shoul have their letter markings facing the same direction. Since the free gear only mounts one way, you then know the direction of the fixed gear. On first gear fixed, the collar faces in. On reverse gear, right above, the collar faces out.

I have replaced the clutch disk and throughout bearing as well.




The engine have received some "while your'e in there" work, like cleaning, powder painting external tins, tubes, fan and fan housing etc. New original plugg wires, as well as cap and rotor. New Rennline engine crossbar and Wewo semi solid mounts was ordered from our host.





I'm also replacing all the lenses, and repainting a few parts. I'll give you all an update when the engine is back in the bay and making that sweet noice again.

To those of you contemplating whether you can do this yourself or not, I say go for it. You are probably not going to save any money, because you'll end up replacing good parts. You should double or tripple you time budget, at least if you're like me making the projects ever larger as you go (I'm now repainting the rear bumber and replacing the lower rear valance as part of this project).
The main justification for doing new things to your car is self satisfaction and gaining knowledge and experience.

[dyerkes]

Great job Arnljot! I'm glad to see it is all back together for you! I agree, rebuilding the tranny is expensive, but it is definitely satisfying and a very rewarding learning experience. Your engine looks great as well. Let me know how it drives once you get your car back on the road.

David

[aseem]

Thanks David. As you can see, i scrubbed the intermediate housing and nose cone with a nylon brush, but too many nooks and crannies in the diff-housing so I only washed it. Next time (maybe I'll need new diffs some time) I would like to strip it all the way down and have the hole case bead blasted. Funny how you get obsessed with cleaning parts when doing work like this. Thats one of the reasons things take time.....

[aseem]

Engine back home!! Put the engine back in yesterday, and had my first test run. I still need to tune the shift coupler a little bit, but shifting feels nice and smooth. I don't know if the new synchros and dogs need no wear-in a little before ultimate shifting is achieved.

It was sooo great to hear that sweet rumble of the 3.3liter turbo engine again.




All I need now before The Turbo is back in duty is to spray the rear bumber and valance, and both rockers. For this job I made myself a paintbooth. I'll post another pic tomorow with fan and "exhaust" vents. I run the booth with a slight over preassure.

[dyerkes]

Congrats Arnljot! I can't wait for the day that I have mine back on the road. I hope you enjoy many miles and years of safe and fun times in your 930!!!

David
1986 911 Turbo

[930turbo]

As indicated in the thread, replace all shifting components or the results could be less than satisfying. engagement teeth are easy to diagnose as worn but what is easily overlooked is the inside diameter of the sliders. They can look like they're in reasonably good condition but if you measure the inside diameter of one with high usage, you'll discover the bore size has increased from the original OEM specs. This can allow the engagement teeth to make contact with the gear teeth prior to complete syncronization resulting in a disconcerting crunch from your freshly renewed gearbox. There's nothing worse than spending the time and money to do it right - twice. If you're that deep, commit to all shifting components (engagement teeth, sliders, balk rings) to avoid disappointment.

[aseem]

For all of you that have followed this thread, I just want to post a follow up. I know this thread is old, but I have seen several references to it, and want to warn others to prevent them from making the same mistake I did.

I don't want to discourage any of you from rebuilding your 930 tranny, just make sure you have all the information.

This happened about a year ago: http://forums.pelicanparts.com/showthread.php?t=348628

After the 930 have been sitting in the garage for about a year, I have finally worked up the guts to go at it again. I don't have all the answers but hopefully this new thread will shed some light on things: http://forums.pelicanparts.com/showthread.php?t=417973

[David]

After following this thread and unfortunately the follow up thread, I'm looking at rebuilding my 930 tranny.

It's shifting OK, but I'd like to replace 2nd, 3rd, and 4th gears.

I can't think of any technical questions that the thread doesn't cover, but I need some sources for the new gears and I want to see what you guys have found.

[quattrorunner]

Sub

[Matt Monson]

Sub

You think he's coming back after 6 years?

[aseem]

I'm still here. Still have the same turbo, but with an upgraded engine.

[quattrorunner]

I just don't have time to read it now but need to to help me with my job.
I wanted to help myself remember this thread.
Aseem how did it all turn out?

[aseem]

Well, unfortunately as you can read in the link a few posts up, the tranny seized on me. Follow the link and read the end of the story.

[Matt Monson]

Well shut my mouth.