RADEoN

iTrader: (12)

Well as some of you may have read in the past, I've been having a ton of trouble with my 04 CTS-V and grinding into 1st and 2nd, as evidenced in this video:

http://www.youtube.com/watch?v=RtNQEpZGjIc





Well, it started out occasionally grinding into 1st gear when rolling to a stop sign, I'd stop, and it would slide right into 1st gear, no problem. It later progressed and got worse and worse, and I eventually had to go from 4th into 1st.

People argued whether or not it was a dragging clutch, or the syncros. I finally settled on dragging clutch, and PISNUOFF/07CTS-V put an LS7 slave, clutch, pressure plate, flywheel, and bleeder extension in. After all this, the issue persisted. Oh well, time for synchronizers.

I drove the car and ground into gear as little as I could, after all it was getting harder to get it into 2nd gear.

A mechanic at a shop I deliver told me it sounds like I didn't get a good bleed on it, and that there's air somewhere in the system. I figured he wasn't sure what I was talking about, and it was still the syncros. Well, I held onto a shred of hope, and while researching new master cylinders, I saw how to bleed one with a mighty vac.

There was a ton of air coming out. I jammed the hose and needle into the fill port hole, put some fluid so it didn't suck air when I pulled it out, and this is what I saw:

http://www.youtube.com/watch?v=Tt438ek38z8


Wow, there's a lot of air to be had! I did that two days in a row, and there was a lot of air both times (but it seems to have been gone immediately after).

Well, my pedal was engaging halfway to the floor, which sucked, but it wasn't grinding nearly as much.

Tonight, I was driving, and I went to put it in 1st gear, and it wasn't working at all, no matter what I'd do I couldn't get it into gear. I'd push with the power of thor, but alas, nothing. Clutch in, clutch out, car on, or car off.

I figured my syncros were finally spent, and I drove the car to my garage to store it until I felt like pulling the trans. While I was there I decided to bleed it from the bleeder extension. I jacked the back half of the car up (is the fluid movement like this relevant?) Man, there was a lot of air to come out of it. I had a friend hold the pedal down, I'd open the bleeder, get a spray (is the spray normal? or should it drip and ooze?), and we did that a few times, and wow, my car not only can go into 1st sometimes now, but it doesn't grind into either 1st or 2nd, but it's a complete bitch to get it into 1st.

So after all this long winded bullshit that you probably didn't want to read, what do you think? Do I yank the transmission, or do I go with a master cylinder?

.Houdini.

iTrader: (1)

I have a motive power bleeder that works VERY well at bleeding the clutch properly. I wonder how your 'mighty vac' works in terms of a comparable/quality bleed? Are you pretty confident that you got a good bleed with all of the air out?

armyboyatc

iTrader: (29)

Since you cant get the car into 1st with the car off, im callin it the transmission.

When you crack the bleeder, you said that it was a "spray". When you say spray, do you mean like air and fluid spray or like a straight stream of fluid that shot out but no air?

GulfM3

iTrader: (14)

Try bleeding it again traditionally.

After my clutch swap I bled the clutch manually and have had no issues.

Can you describe the Mityvac process more clearly. I've never used one. But it looks to me that your mityvac hose is fitted into the line at the bottom of your clutch fluid reservoir, So the idea is to suck all the air out of the system from the top side. Is this correct? Do you have a bottle and hose of new clutch fluid attached to the bleeder screw on the transmission, when the mityvac draws vaccum on the clutch system it should suck all the used clutch fluid and air out of the top side and fresh fluid into the bleeder screw.

punishmentcycle

iTrader: (6)

trying to suck air from the res is always bad news... hook the hose up to the bleeder nipple.. have someone add fluid to the res as u suck the fluid from the bleeder.. once u have clean fluid flowing to the vac. close the bleeder and i always do a couple manual bleeds just to get any trapped pockets of air.. top off the res and go

TexVette

iTrader: (2)

Mightyvac method has worked very well for me for years. You don't want to pull much more than 10 mg/hg of vac or that might cause problems.

Have you checked for visual fluid leaks along the hydraulic line under the car? If air bubbles are appearing like that, means fluid is escaping somewhere.

Details on the "bleeder extension"? Not sure you'd want to use one of those in conjunction with a mightyvac.

May want to pull the shifter boot and visually inspect everything where the shifter mounts as an extra precaution to make sure everything is tight and not causing misalignment going into gear.

I want to vote transmission, because I am sure you'll find problems there, but I feel you're also having a hydraulic issue as well.

DMM

Yeah, vacuuming the clutch hydraulics does not work right. The best way to bleed our clutch systems is to have a person crack the bleeder and have someone slowly depress the clutch pedal and close the bleeder before hitting the floor.

Very, very slow process since the slave cyl doesn't push much fluid at all. This is about the only way to completely evacuate the system of air.

RADEoN

iTrader: (12)

TexVette: the bleeder extension is a hydraulic line that lets us with ls7 slaves bleed our clutches without pulling the trans.

Last night I thought I was bleeding it properly. I had a friend push the clutch the whole way down, I would crack the bleeder, and he would let it back up and I'd close it. Wrong?

Armyboy: I'm able to get it into 1st now, but it can be very difficult, and usually is.

The initial spray of the cracked bleeder looks to spray like an air filled mist.

RADEoN

iTrader: (12)

No edit button on mobile site.

1, I was told that there can be stubborn air in the master that doesn't come out until I use a motive pb or mity vac. True or false?

2, Is there a guide to master cylinder installation?

3, Is it possible my car sitting with the *** end jacked up is part of the reason why it goes into 1st gear better now? I wonder if I have a stuck syncro rather than damaged.

4. Would it be worth it to spray some pb blaster inside the transmission, let it ooze around in there, then drain the fluid?

RADEoN

iTrader: (12)

Just mity vacced the bleeder for good measure, after an entire 30 oz (I think) container of brake fluid, I gave up. So many little bubbles it looked like milk, and so many big bubbles it became discouraging.

There looks to be stains under the master cylinder.

On the plus side, I'm able to go through all 6 gears again with no problem while the car is off. I wonder if this has anything to do with the angle of the car?

I think there's a leak in the master and its sucking air in through it.

85MikeTPI

iTrader: (9)

NOOOOOoooooooo. Never put anything in the transmission but ATF. The blocker rings can absorb contaminants/fluids and you'll have no choice but to rebuild the transmission for $1000+++

Did you ever replace the master as suggested before?

TDP

iTrader: (23)

On a handful of occasions, I've seen very similar problems with the M12 style T56. The root cause wound up being a broken snap ring which holds the 1-2 synchro assembly onto the mainshaft, causing the synchro hub to shift out of position. This will result in engagement/grinding issues with 1st and 2nd gears. On one particular occasion, I saw this happen with a GTO T56 with only 20k miles. The customer had tried repeatedly to get it warrantied at the dealer, only to be shoved out the door with the all-too-familiar "No trouble found" or "Normal operation" diagnosis.
This will eventually cause the blocker rings to crack leading to additional damage.
I'd be willing to bet this is your problem. Either way, it looks like it's time to pull the transmission and get it built. If you are willing to ship it, we'd be glad to get you going. It runs about $75-95 to ship each way.
The tranny already has the steel 3-4 shift fork, but it would still need the billet keys for 3-4. I could go thru and freshen it up with all new rings, keys, springs, fork pads, seals, and upgrade to the billet 3-4 keys. This would run $800 total parts and labor. If any other gears or synchro assemblies need to be replaced, just add the cost of the parts.

Good luck with it and let me know if I can help!

85MikeTPI

iTrader: (9)

Isn't this exactly the problem that you're re-introducing on your 32-spline modifications, by undoing the upgraded 3-piece synchro lock that GM engineered on the late model M12/M10 T56s?

TDP

iTrader: (23)

The answer to this question is NO. I'm sure you know the 1-2 snap ring doesn't just randomly break like this. If you've built a lot of T56s, which I assume you have, you'd know that it's very rare to find a broken snap ring, or a snap ring that has walked out of it's groove.

Being a very uncommon problem, I've only seen it happen maybe 3-4 times. Every one of these had low miles, and it had been an issue since it was new. So it had to be a mistake during the assembly at the factory. My only conclusion is that the snap ring was never seated properly, which led to the other problems.