I'm currently have my transaxle apart to replace a worn pinion shaft 4 point bearing (I'm also replacing the input shaft 4 point bearing). Given this, I have two other items I would like to address.

1. What is the updated spec for 2nd gear?
2. I don't have 2nd hear pop out issues, but the dog ring does have some wear. What are my options to replace this?

Thanks for the help.

Here's a quick picture of the entertainment.





It's not an extremely difficult project, but man is it time consuming. Once you have all the metal dust in there from the worn bearing, everything has to be cleaned, which is as timing consuming as the tear down itself. The main issue is unless you have the correct special tools, you have no prayer of attempting this project.

Here's a picture of just a few of the special tools that are needed. For reference, the smallest socket in the picture is 30MM's and the extra long socket is for 41MM nuts. Thank goodness for knowing a retired Porsche tech for tools and knowledge.



Here's a picture of the bad bearing. Interestingly, the race was chewed up, but the ***** in the bearing still looked new.

 

sorry, dont have the specs ( they may even be proprietary to porsche )..try and make friends with a master p-tech?? ),..
..

but do know the new shim placement changes ever so slightly where 4th gear placement sits in the stack. only guys with the gear stack familiarity can talk you thru that one.

worn 2nd gear dogring = r&r all 1st and 2nd gear synchro's and all associated parts, assuming the gears themselves are not in the least bit rounded. problem is, if the dogrings are rounded, owing to the triple cone synchro's used, the gears themselves may have also taken some "rounding". this would of course require new 1/2 gears.

it isn't guesswork, the parts ALL need to be inspected since once opened, one never knows the condition of the gears vs the synchros' etc. BUT if it IS only 1/2 synchros and the bearings ( all ) that need replacing? consider yourself very lucky. good luck.

 

Also cannot answer your questions but I'm Impress Steve! I have respect for people who dare

 

Don't be impressed until it's back in the car and working.

There's a very fine line between confidence and stupidity.

 

Go GT2RS 1 and 2 (mainshaft) you will thank me later lol......

 

agree! But I have faith

 

gt2 steel syncros as well

 

subscribed

 

i would replace the retaining plate to the GT3 forged version, billets shift forks from CMS are pretty cheap too. just a few things while you are in there.

 

Does anyone have the part numbers for the GT2 steel syncro's?

I'm showing the standard parts below.
996 304 061 50 guide sleeve 1st/2nd
950 304 611 20 Synchroniser ring
996 304 613 20 Cone ring
950 304 617 20 Ring

 

no part #'s on my receipt sorry. these are a few non high hp parts you will also need. there are 2 large locknuts at the front 1 time use need to replace them.

the # on my receipt for the steel syncs are 21130 and thats not a pcar #. if you can't find the # ill call the shop and see what they used

 

how much is the retaining plate? i know the shift forks are 100$ or so stock and 375 each from cms

 

There is no issue with the stock shaft, but the GT2RS has different ratios for 1st and 2nd which work better with modified cars. Basically 1st gear gets taller (which makes it more useful) and the ratios between 2nd and 3rd is tighten up.

Given the cost of this repair, the new clutch and all the maintenance items I'm doing on the engine (welded coolant pipes, new overflow reservoir, etc.), there's no more money for a new input shaft.

New four point bearings, a new 2nd gear and a new 1st/2nd guide sleeve are almost $1,500.

Later, Steve

 

Steve,

Look at the face on second gear and see if there is wear mark from the slider touching. if there is no mark you are getting full engagement. you need a center case with cut outs to see where anything lining up.



The shift forks are not adjustable so you need to shim the stack to get the throw right. You may be able to see the 1st/second gear slider through the oil fill hole in your center case. also make sure you line the the missing tooth up on the 1st/2nd slider with the oil hole on the pinion shaft. I would get the cms shift arrester

http://californiamotorsports.net/col...shift-arrester

 

great! yet another part designed to avoid shimming the gear stack placement correctly and using a part in the transmission that doesn't really belong there. if thats isn't a "stopgap" measure then i don't know what might be? gbox detents/shift arresters?. though i like the 8mm ball bearing best as it makes the most sense from what little i understand of what it arrests ( presumably movement? lol )

while roger at ca motorsports knows his stuff as well as anyone when it come to g50 boxes, why always some stopgap measure is seen as a viable "fix"? just another half assed measure, when shims are all that is needed to update the specs from old ( wrong ) to "new" ( correct ) just my .02.

but i guess it's easier to put in a ball bearing ( best yet ) or gbox's detent, while fixing it "properly" requires opening the box and changing the stack placement by shimming and that's beyond the scope of many diy'rs,.. while a detent or an 8mm ball bearing isn't. i get that part.

whatever works. i'm just glad mine is shimmed properly