seggy

when shifting from 1st to 2nd, but not when shifting from 3rd (or higher) gear.

I had assumed that the synchro is worn out and bought a synchro ring but our attempt to change it failed when we couldn't get those dowel sleeves out from the tranny ... I guess dismantling the tranny isn't for beginners <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />

Any tips on the sleeves? And is it normal behavior, when the 2nd gear synchro wears out, that the gear grinds when shifting quickly from 1st but not from 3rd??

wa944

Having never torn apart a 944 trans, I can't help with the sleeves. But as far as the synchros go, there is typically a sychro in between each set of gears. The 1-2 wearing out before the others isn't uncommon for 2 reasons: a) it's the gear change most often made, and b)1st and 2nd gears have the highest torque multiplication and the largest rpm speed differential to match. Hope this sheds some light.

wa944

Sorry didn't mean for the second one. Hit the back button. Oops! <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" /> Any way, The synchros normally use a cone type clutch. Once this friction material wears off, it may no longer be able to slow down the shafts quick enough. When this happens, the dog clutches will grind as the collar trys to force force it's way over the inner "ring" portion. Figured I'd try to expand over the last one since I can't delete it. I wish you the best of luck.

David Salama

I recently had my transmission rebuilt when I had my LSD installed. The shop told me my number two synchro was fine, and did not recommend replacement. I have never been able to shift quickly between 1st and 2nd gears without grinding. I think personally that the transmission design does not allow for this. On down shifts from 3 to 2, I have no grinding even without matching revs which confirms the synchro ring is functional. I believe you simply have to take your time shifting. How is everyone elses shifting from 1 to 2 ?? I especially run into problems when the transmission is cold and the boost is just hitting when I decide to shift. Hope this info is helpful.

art

I'm doing this now, getting the trans apart is involved, and getting to the 2nd gear synchro is very involved. If you have some experience, good tools and can think it through it is not impossible.

Mine is not back together yet, but I will report when it is as there is no chatter on this stuff at all. I had a bad pinion bearing, and the syncros are cheap and easy to change when doing other major work. The risk is that the gear itself is also worn and replacing just the syncro may not work or will only work for a while. Based on my measurements I think I will be OK.

Art

NerfRacing

my tranny is quirky like that too, if i shift into 4th too fast it will grind, but downshifting is no problem. oh well, i guess its one of those things you've just gotta deal with.

Jeff928S4

Mine grinds going into second only when the car is extremely cold.

944S Boyeee

seb928s

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by 944S Boyeee:
<strong>Mine grinds going into second only when the car is extremely cold.

944S Boyeee</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Mine is the same and I just changed the oil to Swepco it seemed to help it out a bit I have this problem when shifting at any rate when it's really cold it will grind a bit if I don't do it really slow. It's always on the first shift to second when the car is cold after that I have no problem. If it's warm I can shift it fast without anything.

jimbo1111

I would bleed the slave cylinder on the clutch or replace it. sound like the pressure plate is not 100% releasing from the disc when shifting.

seggy

weird.....mine actually grinds when warm, not when cold! When I just got the car it use to grind as and when it likes, regardless of cold or warm, but after the failed attempt to take the tranny apart, I put in Redline MTL and now it only happens some of the time when warm, but very seldom when cold.

wa944, thanks a lot for your detailed explanation. If there is a set of synchros for each set of gear change, how come the synchro rings sell by which gear, not gearchange? Not doubting your explanation, just eager to learn something new

pedro951

mine grinds any time im not gentle or dont match revs up to 2nd or down to 2nd. ive always assumed it was the synchro.

wjk_glynn

</font><blockquote><font size="1" face="Verdana,Tahoma,Arial,Helvetica,Geneva">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">Originally posted by David Salama:
<strong>I recently had my transmission rebuilt when I had my LSD installed. </strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Arial,Helvetica,Geneva">I plan to install a LSD in my transaxle as well. I was wondering how much you were charged for parts & labor.

Thanks.

Karl.

IanM

Mine also grinds when shifting from 1st to 2nd when cold. After about a minute of driving it's not a problem.

seb928s

I think this is normal when it grinds from 1st to 2nd when cold all the Porsches I drove have done that even the 911s with the 915 gearbox, but once it gets warm it's fine not a problem like Ian said after a minute.