^ Agree ^

The crabby "elders" who run the "CF sewing circle" typically have no technical response, just a lot of rules that are easy to impose on newbees.
Expect to be admonished for:

1. Bringing up old threads when you've done your research and found threads relating to your issue
2. NOT using the search feature if you make the mistake to just start a new thread with your issue
3. Not reading your manual where your issue is obviously described in detail on page blahblahblah; paragraph yadayadayada.

As said, ignore these who have no answers for you under any circumstance. Believe me, more members roll their eyes over these members' posts than they do you as a newbee.

I, for one, agree with Dano. His post is (and are) comprehensive, technically accurate and complete. I'll add that, given the age of the C6, CAGS has usually been eliminated by now, but you're not describing a CAGS issue. You're more describing a 2nd gear synchro issue. Tremec transmissions use a fiber lining on synchros these linings are sensitive to trans fluids and can be impacted when owners experiment with aftermarket fluids. More likely that you have a problem in the synchro than other places.

 

Yes, no, maybe,

When you have problems with the friction disc on the synchro not speed matching the gears, the trans ends up grinding as your trying to shift into gear.

When the trans has been forced sling shot into gear isntead (not allowing the syncro the needed time to lock the gear down to align match them).
This causes wear/peen'g to the inner synchro slots and the gear tabs it rides again to hold it in place, and the two gears end up going to point to point as the slider is trying lock in place, to block out the clean back bump mesh isntead.

So a lot of people get hung up on this peen'g,


But that problem an after math of the alignment u slot of the ring begin peen open/damaged, and/or the gear tab the U alignment slot it rides on being peened narrower to allow the gear to over rotate in the first place from slam shifting.


So the most we want the tips to move against each other is this far,



So when the slots and tabs wear to allow over rotation of gear tip to slider tip, it allow the tooth tips to go tip to tip, and this causes the block out.

So again, grinding into gear is the friction disc worn and not locking up the synchro gears for the slider to move cleanly into the gear.

Block out alone comes from the gear to slider tips over rotating after the synchro has locked up the gears togheter, and you get no grinding noise instead.


So if the problem is not a CAGE problem that is blocking out the shift, or the clutch not fully disengaging to allow a clean shift, and your not having problems of say shifting into 4th with the shifter coupler bolt loose~shifter/shifter box not indexed correctly, then bank that is time to pull the tans apart to rebuild it. AND, learn how to shift correctly (allow the synchro enough time to do there thing instead of slam shifting into gear) so your not tearing the hell out of the trans and having to keep rebuilding it over and over again!!!