veee8

iTrader: (40)

Well the story goes.....
I left NC to go on a road trip. All was well cruising in sixth on the highway, as I pulled off the highway to come into my grandmothers town at 1 am, the transmission started grinding when attempting to downshift into second. I thought "that's weird", but it didn't go away, and did it every time I tried selecting second, upshift or downshift. Being 1500 miles from home, I drove around for a week, by starting in second, and carefully not selecting that gear when the car was moving. Major pain in the ***, and bummer, since the 1-2 shift is so much fun!
So I called in some help in Detroit, enlisting my good buddy Brian Tashman to get this thing fixed. I figured it was just the synchros. I went to Gearbox Transmission Inc for the parts, which they happened to be right down the street from where I was staying.
I picked up a custom Stage 2 kit for the T56, V specific. There are some differences that I wasn't aware of. The V uses the triple synchro setup, like the GTO and Vette. Which unfortunately about doubles the price of the kit! My V also had the upgraded viper steel 3-4 shift fork from the factory.
The kit consisted of
* Upgraded 1-6 carbon fiber/kevlar blocker / synchronizer rings
* Reverse synchronizer ring
* Bronze fork pads for the 1-2 & 3-4
* Billet keys for the 3-4 with upgraded springs
* Billet keys for the 1-2 with upgraded springs
* Bronze shifter bushing / isolator cup
* 1-2 synchronizer assembly
* 3-4 synchronizer assembly
* Snap ring kit
* Stock 5-6 & reverse fork pads
* Stock 5-6 & reverse keys & springs
* front & rear seals

Unfortunately, after tearing the trans down, we found more carnage. Which was a shock, the trans didn't make any noise, and outside of the new second gear grind, had been fine up until then.
The reverse gear had a ton of shaft play, was quite loose. The caged bearing was toast, and the spacer was ground right into the gear. The 5-6 driven gear slid right off the shaft, the splines were toast. The manishaft splines were also wore about in half. The CTS-V mainshaft is specific, due to the bolt on prop shaft yoke. That was the only part that had to ordered. I'm still sore after the shipping on that one. Next day air, Saturday delivery!
I had exactly $1500 in parts alone, and I'm in the industry with connections. Thank goodness I have contacts all over the world in the LS community.
Upon recommendation, from others, I ditched the Royal Purple ATF, I was running, for around 4000 miles, to good old Valvoline Dex/Merc non synthetic.
Everything is working good, and the trans is now good for 650hp/tq. So I'm good for a while!

So here are some photos........

Some teardown and carnage...







5-6 driven gear splines



Mainshaft splines







Here are some of the new parts....




Cleaning and reassembly...





The viper steel 3-4 shift fork







The carbon fiber synchros getting an overnight ATF bath











The brand new CTS-V mainshaft























All buttoned up and ready for re-installation.

VmanUSA

iTrader: (1)

does this include an upgraded/hardened output shaft? This is what I am going to need next for my ride I think. thanks for the info!!

ColeGraham

iTrader: (8)

I am thinking about doing this after i get my new clutch. looks very nice.

9 and a Stage 2 tranny...you are going to be having some real fun with the V now.

raven154

iTrader: (14)

How much to rebuild mine? lol

veee8

iTrader: (40)

It is a stock Tremec mainshaft (output shaft). That is all that is available, other then having it Mikronited or chryogenically treated.

The rebuild was very straight forward, and actually easier in some areas the old Muncie 4 speeds. The modular design makes it quite easy to service. Expect to pay $2K+ for this.

killernoodle

A little more than that is a new or almost new TR6060 from a camaro or a G8. Externally, they look identical to the V tranny, I'm pretty sure they would bolt up. They have the linkage shifter and the triangular output shafts as well.

veee8

iTrader: (40)

I had a 2010 0 mile 6060 sitting at the shop, I have looked them over, they do appear to be quite similar, the shifter setup is a bit different though.
But.....the 6060's have a lot worse sychro problems then late model T56's. The 6060 went back to a double system.

raven154

iTrader: (14)

Hey I was wondering if you could get me a few part numbers? I have a local guy that has done all the work on my trans but I buy the parts. He only charges me 200 labor to do everything so thats not to bad.

I know I need part numbers for the input shaft, 3rd gear, 3-4 syncro and blocker rings. I have billet keys, bronze fork pads, but I would also like the bronze shift cup if you could provide any info on that as well! Also, the trans has 95k miles and is still on the original bearings for the most part. Anything I should look out for? Anything I should replace with this many miles?

Any help you can provide I would appreciate!

Bobby

veee8

iTrader: (40)

Here is where I got all the parts from. He has everything you want right there. Just give him a call. Ask for Kevin.

http://www.thegearbox.org/T56_corvette.html

They say the bearings are not recommended to be changed untill something like 150,000 miles if needed. They are high quality Timken from the factory. I had the reverse roller bearing fail, but so was the gear, shaft, and 5-6 gear.
Apparently it is fairly common to have that stuff go bad. It is in the extreme rear of the unit, lubrication is important. Especially lots of assembly lube when you rebuild. It takes a little while to get the fluid in all the spots. The 5-6 driven gear, does not have a lot of spline material on the shaft, they should have extended the splines further, the gear is like 4 inches long, but the splines are like 1.5 inches or so.