Gearbox issue - thoughts gratefully received

I would remove the engine as a very last ditch effort, and try to find a solution from under the car.
Possibly the detent ball springs?
Linkage adjustment? Shift rod adjustment? Really difficult otherwise, without being there.
You might ask in the tech threads.

Regards, Alberto

 

I agree with Alberto. You can do quite a bit of adjusting and double checking by taking off the gearbox bottom cover while still in the car.

 

Snowy,

You may want to check the gear linkages/selector forks are aligned. After re-alignment this sorted out my problem with jumping out of first. At the bottom of the following thread are some pictures of each gear setting from inside the gear box. It's a fairly straightforward check. Only downside is having to clean/re-seal the gear box and new oil.

http://ferrarichat.com/forum/showthread.php?t=226569&highlight=Gear&page=3

Kevin

 

This is the reason why it is important to run the engine out of the car before installation, and while at it, go through the gears.
It gives peace of mind and so much more fun than pulling the whole assembly out of the car.

I have never put a motor in, but would certainly hate to take it out as it does not look like there is a lot of space and tons of work.

I think you will be able to solve things out from below.

Regards, Alberto

 

I recently had the o ring on my selector shaft replaced as there was an oil leak,the process was to put the car on the hoist remove transmission plate,remove shaft and re- instal with new seal.All sounds easy,this took about 5hrs.When I took the car there it was also jumping out of 1st gear,the car was driven around the block lost 3rd and 5th gears, back on the hoist pan removed more adjustments by someone who knows their stuff not someone who thinks they no, problem sorted.Hopefully adjustments are all you need good luck.

Johnno

 

Great info Snowy! Food for thought, and an experience well worth sharing, as now we know more.
I am glad things are looking brighter.

Regards, Alberto

 

Thank you for the information. For anyone re-building a gearbox I was told a great money saving tip.

The gearbox uses 5 synchros (one per gear) and 3 synchro hubs. Each synchro hub is 2 sided so one half takes care of one gear while the other takes care of another. As such the synchro hub that is used for 1st gear is only ever 1/2 used with the other side never seeing service. When taking the gearbox apart if you flip the 1st gear hub you will now have a brand new never used side to operate 1st gear thus saving the purchase of 1 synchro hub.

 

Great tip....
I might have to disassemble again? Oh, Noooooooooooooooooooo.
I will look in there tomorrow, it's 50/50 anyhow, really good odds.

Regards, Alberto

 

Also note that Porsche-sourced syncrhos fit, are cheaper and better.

 

Hello Tryfon, which model please? Does they fit all versions or only the late ones?

Regards, Alberto

 

Some 911 don't know which but ask any vintage Porsche mechanic, he should know or show him the part and he'll tell you. If you run into trouble I will ask. These are a direct replacement for 246E and Stratos of course. Better, stronger, cheaper. Reminds of the good old days of synchro gearbox. Dog engagement is the dog's b.... though.

 

Thank you Tryfon

Regards, Alberto

 

It all sounds familiar, I had my engine out twice for a host of reasons, and the lesson learned was that if the gears work before you take out the engine they wont necessarily work when it all goes back. If the box has been rebuilt as well then you are in for a megga session adjusting it. For the record I used superformance synchros and all was ok. After lots of frustration with gears jumping out or not going in, my solution was to sit my 16 yr old under the car with the cover off, equip him with appropriate spanners for the forks and main rod and spend hours adjusting it. My role was to sit in the drivers seat changing gears and drinking tea. The settings really are very sensitive, and every time you tighten it all it just moves enough to stop it working again! Its one of those jobs where by the time you are slick at it and could do it quickly you will hopefully never do it again. I wouldn't be at all surprised if your box is fine

 

Should have been the other way around, you under the car and the son changing gears. It's below the car the delicate work takes place.

 

Thats why I put him there. That young brain worked out how it all worked with everything upside down and back to front quicker than I could!

 

There is an 'H" shaped, very simple tool, a DIY, that is used on the bench to adjust the forks, and I have been told that it makes matters quite simple, and does not require such efforts.
Anyone use it? I made one for my series 'L' box and it appears to be very effective.
I guess when installed, we shall know.

Regards, Alberto

 

356

 

246 fork adjustment is quite easy although you do need a special tool to retain the detents and springs while the cover is off.
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Exactly. We use a similar tool for both the 3x8 cars and the Boxers. It makes life just so much easier.

 

Quite different from "L" series tool. Function, quite the same.

Regards, Alberto
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Here is a more detailed explanation of Rob & Paul's hot tip that will save you hundreds

http://dino246blog.blogspot.ca/2012/08/an-odd-issue-lets-you-get-even-with.html

Gearboxes are an area in the Dino where the cost of parts can really surprise you at how quickly they add up.

Thanks for the great tip!

Forza

 

You can reverse all synchro rings.