theandrewo

Did a 1-2 speed shift the other day and it locked me out and ground hard. Since that day, I can’t shift 1-2 over 4k rpm or it’ll lock me out and grind. This happens on upshift or downshift (rev matching). Clutch fully depressed. Shifts fine under 4k rpm. All other gears shift fine at high RPM. 1st/reverse slide in easily. Clutch does not slip under load.

Car:
’08 z51 6spd
41k miles (purchased at 33k)
TMODD short shifter
Tick Clutch Master Cyl (just installed)
Fresh Lucas dot4 synthetic clutch fluid
Amsoil Torque drive transmission fluid (changed about 5k ago and looked good)

History:
Never had any 1-2 grinding issues. I always warm up the transmission before shifting hard. Never no-lift shift. Rarely if every missed a 1-2 shift. Historically, I HAVE had a sticky/falling clutch pedal when after doing a couple hard pulls. Which is why I just installed a Tick master, but my grinding symptoms did not change. Prior to installing the Tick master I flushed the fluid regularly (Ranger method), due to the sticky pedal under load.

Could it be something other than the synchros?

Dano523

Burnt/worn out synchro in the trans, as well as some gear wear as well.

Short version, you first have clutch material of the syncro that will speed match the gears as you go to shift.
The next one after the speeds have been matched, the gear has to arrow tooth to arrow tooth match to allow it to go into gear. Some times it the points of the arrow type teeth that are worn enough that it will not allow engagement, while other times its the inner slots and tabs that peen/wear too wide, that allows the arrow point gears to over rotate on each other (tip to tip) and will not allow them to final engage isntead.


Bottom line, either wrong lube used in the trans to cause the clutch pack disc to wear to fast/ not speed match the gears fast enough, or sling shot shift to the point that the clutch pack can not speed match the gears in the first place (the initial grind noise), to cause the wear to the grooves/tabs, or arrow gear to arrow gears tip wear that will not allow the gear to final engage.

Note, T6060 trans is a T-56 magnum trans, so video below will cover both trans in regards to syncros.

Bottom line, trans has to come apart, to be serviced/worn out parts replaced.

Dano523

Again, T56 and T6060 synchro clutch material is designed to be use with a specific lube for the longest life of the sychro clutch type materials (blocker rings).
Lubes that are thicker, or slicker, may not allow the clutch synchro to grab fast enough on fast shifts to speed match the gears, and will cause the arrow gear tip to tip mashing, as well as slot to tab wear/peening as well.
Note, rear diff has clutch packs as well, and wrong lubes used here that are either thicker or slicker, will end up with peg leg burn outs when the Diff LDS clutch packs are not holding to 100ftlb break away values.

So my suggestion, if you don't want to use the GM recommended lube in the trans, then when you are replacing the sychro in the trans (blocker rings), they get replaced with ones that will work well for the lube your going to be using instead.
https://www.tickperformance.com/trem...60-t56-magnum/


As for the Tick(clinton) Clutch Master Cyl (just installed), make sure you have it adjusted correctly.
Hence it will allow over throw of the clutch since it moves more volume of fluid per stroke than the oem cylinder (even with the pedal rod post moved on the pedal), and should have between 1/2'~3/4" free movement slop at the top of the pedal stroke. Down and dirty, adjust more free slop to the top of stroke to begin with (1" pedal top downward movement until you start to feel the cylinder start to build pressure), and decrease the top pedal slop just enough that you can just shift into reverse cleanly with the pedal fully depressed and the motor running.

https://www.tickperformance.com/tick...te-c6-z06-zr1/

Spaceme1117

I think you have some internal transmission damage. And the only way to figure that out is to pull the transmission and take it apart.

theandrewo

I was afraid of this answer, but after my own research and your response here it sounds like the blocker rings are likely to be the culprit. I'm guessing it was the slingshot shift. Countless other members here are running Torque Drive trans fluid in their TR6060 with positive reviews. What makes you suggest the potential for gear wear as well?

These look like a good option for replacement.

I think I got it adjusted about right. I wish Tick provided more information on adjustment. I've got about 3/4-1" pedal slop, and the pedal is about 1" below the brake pedal (prior to depressing). 1st/reverse slide in nicely. The rod is adjusted most of the way in, and the clutch engages close to the bottom of the pedal. Gonna take some getting used to.

How will these synchros affect the daily drivability? As long as I avoid high RPM/quick shifts from 1-2, can I continue to drive around? This trans problem is ill-timed, as the transmission went out in my daily driver about 4 days ago, so the vette is now my daily.

Dano523

The problem when the locker rings do not get the gears speed matched fast enough, you start to peen the hell out of the tabs and slots, ending up with the arrow tip to tip gears over rotating against each other, and this causes the arrow gear tip to tip wear as well.
So what used to be a little over rotation and the tips not even tip to tip to allow back rotation to slip into gear, end up with the arrow gears tip to tip instead. As the arrow tips grind down against each other to widen the tips (or channel spines bur as well), tip to tip off set alignment gets worse as they become duller/peen to hell against each other, and will block out more since they can not even be forced to back rotate to allow engagement instead.



Simply put, if you want to sling shot shift with a manual trans, instead of allowing the locker rings enough time to speed match the gears at shift for smooth shifts, then it time for a sequential transmission isntead. The engine will blip on the shifter handle pulls, you don't use the clutch, and blip is enough time/enough pressure off the U locks to making lighting fast shifts isntead. The down side (over that fact that that trans is around $28K), is most sequential transmission for the C6's are straight cut gears, so loud as hell in regards to whine.
________________________________________ _______________________
Or just keep sling shot shifting and plan on more trans tear downs to keep replacing worn out parts from it.

theandrewo

Thank you Dano523, you've provided some very valuable and educational information here.

When you say "sling shot shifting," what exactly are you referencing? Quick shifts?

Dano523

Your shift should be about the count of "One and Two", from the time you pop it out of the first gear, and put it into the next gear.
Not just a huge rip out of one gear, and rammed into the next in less than a 1/32 of a second; before the lock ring can get the gears to speed match for a clean engagement isntead.