T56 expert help needed

[matt_w]

So I finally got my v8 Z put together and running, and everything seems ok when driving around town. However, I noticed that if I put it in 5th/6th gear, there is a terrible squealing sound coming from up front (not sure on the exact location). The sound starts not when you put it in gear, but when you apply the gas. I noticed that the bellhousing was contacting the transmission tunnel in a spot, so I bent that area back and now there is about 1/2" clearance between the trans and tunnel. I put it in 5th gear under a few conditions after fixing this issue and this is what happened:

 

1: Doing ~40mph, put it in 5th, no sound

2: Doing ~ 45mph, put it in 5th and stomped the gas, no squeal

3: Doing about 35-40mph later in the evening, after about 5 seconds in 5th, it starts to squeal.

 

My original theory was that due to the ratio of 5th/6th, shifting into them at low speed was causing a large amount of vibration as the engine got loaded down. I guess this could still be the case (if it's contacting in an area that I don

't see). I do know that the 5th/6th share a synchro, so I fear it may be the transmission.

 

I rebuilt the tranmission myself, and I guess it's possible I messed something up. I wouldn't know where to start looking though if I tore the trans apart.

 

Also, if anyone cares, here is a vid of my freshly put together z!:

Edited August 16, 2011 by matt_w

[Blown77Z]

So I finally got my v8 Z put together and running, and everything seems ok when driving around town. However, I noticed that if I put it in 5th/6th gear, there is a terrible squealing sound coming from up front (not sure on the exact location). The sound starts not when you put it in gear, but when you apply the gas. I noticed that the bellhousing was contacting the transmission tunnel in a spot, so I bent that area back and now there is about 1/2" clearance between the trans and tunnel. I put it in 5th gear under a few conditions after fixing this issue and this is what happened:

 

1: Doing ~40mph, put it in 5th, no sound

2: Doing ~ 45mph, put it in 5th and stomped the gas, no squeal

3: Doing about 35-40mph later in the evening, after about 5 seconds in 5th, it starts to squeal.

 

My original theory was that due to the ratio of 5th/6th, shifting into them at low speed was causing a large amount of vibration as the engine got loaded down. I guess this could still be the case (if it's contacting in an area that I don

't see). I do know that the 5th/6th share a synchro, so I fear it may be the transmission.

 

I rebuilt the tranmission myself, and I guess it's possible I messed something up. I wouldn't know where to start looking though if I tore the trans apart.

 

Also, if anyone cares, here is a vid of my freshly put together z!:

 

 

What RPM is the engine at in 5th gear @ 35 mph? My LS1+T56 has a terrible bog in 6th gear if the RPM is @ 1.5k or lower.

 

Have you checked for any squeals while the tranny is in neutral? Try running the RPMs up and down while in neutral.

Edited August 16, 2011 by Blown77Z

[matt_w]

I was a little over 2200RPM in 4th before I switched to 5th I think.

 

I forgot, I also had the car up on jack stands with the engine running and put it in 5th/6th and there was no squealing sound.

 

There are no squeals or sounds when the tranny is in neutral. Just the normal throwout bearing faint rattling sound.

Edited August 16, 2011 by matt_w

[matt_w]

Well, looking back through the T56 schematics, looks like 5th/6th gear both ride on the same shaft. I guess that means I have a bad bearing somewhere.

 

Looks like I'll be doing T56 rebuild #2 pretty soon