I roadrace my car regularly at HPDE's, and I've already replaced the synchros once already, but now I've come across a different problem. The tranny will not shift at all in high rpm, anything over 5k I can't get it out of gear, and once it finally does come out (after 3 seconds or so) it won't go into the next gear. And while applying pressure to get it into the the next gear, i can hear a winding noise (not grinding). I doubt its the clutch, it doesn't creep or anything unusual while the clutch is engaged. I've rebuild again yesterday, using a rebuild kit, which replaces all the synchros and most of the major bearings (on the outer ends of the shafts), but the problem is still there!! The only thing I can now think of is that the kit did not come w/ the needle bearings (in between the gears and the shafts). Could this be the problem? anyone w/ any info would be greatly appreciated. Thanks in advance!


Modified by Drive01 at 8:05 AM 8/12/2006

 

does the car creep forward or idle low with the clutch disengaged while in first gear at a stop?

sound like it is the clutch and its not disengaging all the way.

 

no, it doesn't creep, and it goes into all the gears just fine while stopped. This only happens when i drive at high rpm. normal driving the car shifts fine.

 

what clutch and lubricant are you using?

does it do this on upshifts to all gears?

downshifts okay?

the winding noise to me suggests the synchros are being way overworked and are having trouble slowing the mainshaft down to the desired speed during an upshift.

when you are applying pressure to the next gear as you said, do you hear the wind and then it subsides before slipping into gear?

[e] You said this problem only arose AFTER you put in the new synchros??? If so I'd bet somthing in the installation must be amiss. are the symptoms the same when the tranny is hot and cold?

 

^^^^ Reading ownz joo...


Did you replace the syncro sleeves while you were in there? More often than not, the sleeves are what needs replacing, and not the syncros them selves... Not always but its more common... (From what I've seen)


What was your torque reading when you re-installed the two shift-rod ball bearings? That is also another problem you could be having.... You need to drop your tranny and take another peak inside. Check your needle bearing races to see if there is any abnormal where... Did you make sure and place the syncro springs back correctly? I've done this before...Not correctly installing the syncro spring... Tranny did some great things... sigh...

LMK

 

Does the mainshaft spin freely in and out of gear when rotating it by hand (transmission on bench)?

 

you might want to check the clutch. i just had a cm fx700 that had 100miles on it and after it got hot i was unable to shift in or out of gears. another thing to try is to check all clearances