llafro

I am having trouble shifting my T56 LS1 GTO. It only appears near redline and full load. Shifting from first to second or second to third is essentially blocked until the RPM drops. It comes out of gear normally, but won't go into the next gear.

Normal driving is not affected. It shifts the same way it always has. The car has an LS7 clutch setup that was installed about 60k ago. It's a daily driver. I wouldn't be surprised that it needs a new clutch, but is there anything else to check first?

Chris Paveglio

iTrader: (2)

If you search more, you will probably find that there is something with the self-adjusters on the (assuming stock) clutch that IIRC dont allow for full disengagement at top RPM.

stoverz28

iTrader: (8)

Is the master adjusted properly?

gesto

If those don't help, try bleeding it.

llafro

The master cylinder is a stock non-adjustable type. I will have to try bleeding it. It has a remote bleeder on it that makes it a lot easier. It's also got a noise shifting 1-2 and 2-3 that sounds a lot like synchros (slight whining/whirring). It's getting up there in miles (105k).

The engagement point is the same place it has always been, towards the top of the travel (last 1/3 or so). There is no drag on the trans from it not releasing. I put it in first gear and revved it to over 5,000, and no motion forward with the clutch released.

llafro

The transmission has a whining noise in first, second and third. It gets louder when shifting. The noise is gone in fourth gear. From what I have seen, it sounds like a bearing problem, combined with worn synchros.

Here is a Youtube video of the sound. It's hard to film and shift at the same time. I had the phone in my hand while shifting. But, it's the sound that's important...

HioSSilver

iTrader: (8)

It's probably your pressure plate op.

ls7 clutch is a overweight pile of poo.

llafro

HioSSilver

iTrader: (8)

I had a t56 that whined but was fine. But there could be a issue there. More times than not high rpm shift issues is the pressure plate.

92rslt1

Did you ever find out the cause? Mine does the same exact things. Hard to shift hot and whines like yours.

AMP-D

If your transmission is whining in 1st-3rd, goes silent in 4th and develops noise in 5th-6th, most likely it is your input shaft and counter shaft that is worn.

As for the lock out at high RPMs, it very well could be the pressure plate creating this issue by not being able to overcome the centrifugal forces being applied at those RPMs. It could also be that the hydraulic cylinders (either one) isn't apply enough movement to the release bearing to completely unload the pressure plate at high RPMs. I would go with the pressure plate being the issue if I had to choose.

Stampede4ever

What do you guys recommend for a stock replacement clutch? I've heard good and bad about the ls7 clutch that was my plan for a clutch a good stock replace type clutch that could handle 500 hp and that wad affordable.

Thanks