What are the symptoms of syncros going out?

**grandkodiak** · 02-09-2006, 08:02 PM

What symptoms would exist at the time where your syncros would be goin on thier way out...?

**Danger731** · 02-09-2006, 08:36 PM

grinding into gear even at low loads..

**lrader99** · 02-11-2006, 06:47 PM

agreed. most common is the 3-4 syncro gives out....between the damned factory paper blocker ring linings and the stamped strut keys... its easy....down shift from 4th into 3rd at about 130.....it will snap em almost every time....both times i snapped the fucking keys it was doing a hard mash em session down a long straight stretch and right before i hit the corner i was goin 160...so i downshifted 5th - 4th no problem then when i went to downshift from 4th to 3rd it wouldnt go out of gear...strut keys will snap and both times it happened to me the bits of keys got stuck between the blocker rings and the syncro assembly not allowing it do disengauge the gear...after all the little bits of keys finally got collected up by the magnets it stopped whining, but then whenever you upshift from 2-3 or 3-4 it will grind... if you upshift from 2-5 then dont release the clutch and drop it back into 4th, most of the times it will line up the syncro... the problem is this....4th gear is part of the input shaft....it doesnt come off...so if you destroy the clutching teeth or mar up the gear you will have to completely disassemble the trans cause guess what...the input shaft is the VERY last thing to take out... the gears are ordered like this in a T-56 from input to output:
i(nput shaft 4)(main shaft 3-2-R-1-5-6) plus theres also a counter shaft and the reverse shaft and idler gears.....so in other words......DONT DRIVE YOUR T-56 for very long if you syncros start to go bad......if they do buy the master rebuild kit with billet strut keys and kevlar blocker rings....make sure the clutching teeth are still pointed...if they are rounded what you will do is you will imediately start wearing out the blocker rings and yet again fry another syncro assembly....once you install lthe new blocker rings and check the blocker ring to gear cone clearance....the gear has a cone shaped race the the blocker ring sits on ...what happens is that as the blocker ring slide onto the gear and grabs and speeds up the assembly so that you have smooth engagement and dont grind...when you dont have the apropriate clearanceI(the blocker ring sits too close to the gear) the syncro has a hard time lining up and it can/will cause gear clash and or fry the syncro or the dog teeth on the blocker ring

HOPE this has been a help

**grandkodiak** · 02-12-2006, 02:41 PM

Definatly has, it sounds like mine are ok and its nearly entirely just a bad clutch issue. i've savin that tidbit though, great info to be able to reference later. i know little about transmissions, something i frequently overlook...

**eb52hill** · 02-12-2006, 03:43 PM

Judging by what you are saying, I think my sync is shot. I'll be pulling the tranny to swap clutches sometime next month. This may sound like a stupid question but where can I pick up the rebuild kit spoken of? I might as well fix everything while I got the bottom torn out. Thanks.

**lrader99** · 02-12-2006, 06:46 PM

ebay...t-56 master rebuild kit
tools needed:
pilot bearing puller
snap ring plier(2 kinds, 1 for the eyelet type 1 pair for the bearing style snap rings)
gear puller that is capable of pulling from 20" +
without these tools you will not be able to disassemble your trans....on top of that...you will have to press on all that you pulled off