Cascade Crew

DBL_TKE · Last edited by DBL_TKE on Sun Sep 11, 2011 4:05 pm; edited 1 time in total

So I just got a '91 Z28 with an LB9 and T5. The previous owner put a new clutch in approximately 400 miles ago however it has a lot of clutch chatter. It's about as violent as wheel hop shaking the whole car. It only happens when I'm slipping the clutch between around 800-1500 RPM's. What could cause this? A non resurfaced flywheel? Loose flywheel/pressure plate bolts?

Also I just noticed that this trans likes to grind going into only 4th gear when I'm shifting at high RPM's (4k+) Otherwise it shifts perfectly into every gear under normal driving. I was thinking about doing a trans fluid flush and running synchromesh instead of ATF. Does anyone have any ideas what can cause this issue though?

chevymad · Posted: Sun Sep 11, 2011 4:05 pm Post subject:

Contamination, bad surfacing, bad clutch hub, motor mounts..

Twilightoptics · Posted: Sun Sep 11, 2011 5:44 pm Post subject:

Grinding into 4th only is a bad synchro, or a mis-aligned bellhousing.

Alphius · Posted: Sun Sep 11, 2011 6:40 pm Post subject:

Also, if by some chance the dude put in a ceramic puck clutch, that could be a lot of the chatter. Could be bad clutch hub, poor flywheel surface, warped pressure plate.

The grind into 4th could hardly be anything else except synchro trouble.

Twilightoptics · Posted: Sun Sep 11, 2011 7:37 pm Post subject:

DBL_TKE · Posted: Wed Sep 21, 2011 11:13 am Post subject:

While I had the car on the lift the other day I was taking a look at things and noticed that there is one bolt missing from the torque arm mount to the tailshaft. I wonder if that is causing enough play in the torque arm mount to vibrate like crazy? I'm also 99% this is a nothing-special stock replacement clutch. Another thing I noticed is that there is excessive bearing noise with the car is neural with the clutch out, push the clutch is and silence. Input shaft bearing?

aaron_sK · Posted: Wed Sep 21, 2011 12:47 pm Post subject:

Twilightoptics · Posted: Wed Sep 21, 2011 2:09 pm Post subject:

Alphius · Posted: Wed Sep 21, 2011 5:40 pm Post subject:

Paul is right, I have anecdotal evidence and logic:

I may have a bad input bearing, it growls on cold starts only when I park uphill but goes away when ATF gets tossed into it, the only way to shut it up is to get the clutch all the way to the floor, then you can hear it die off as the tranny stops spinning. A TOB noise should go away with moderate clutch pressure, but not necessarily all the way down.

DBL_TKE · Posted: Thu Sep 22, 2011 10:41 am Post subject:

From what you guys have been saying I've determined that it's my input shaft bearing. Noise only goes away when clutch is fully disengaged. I'll be putting my car on the lift again today to add that missing tourque arm mount bolt.

Twilightoptics · Posted: Thu Sep 22, 2011 12:17 pm Post subject:

Change the trans oil and drive it. Input bearings on t5's are weak. If you pull the trans out for any reason, change the bearings.

DBL_TKE · Posted: Thu Sep 22, 2011 10:21 pm Post subject:

Alphius · Posted: Thu Sep 22, 2011 11:05 pm Post subject:

T5s just make odd noises sometimes. It's the nature of the beast. Wink

I have a NWC T5. Unknown mileage. My input bearing has been noisy for thousands of miles. Input shaft splines are twisted where the clutch sits. Case is not straight. About 5 bolts on the tranny are heli-coiled. I beat the crap out of it (clutch drops and powershifts) and it comes back asking for more. Shifts smoooth too. Laughing

Better than my Subaru and better than my dad's short-stick T56.

Run it 'til it dies. It might surprise you. I know mine has. I do have a spare sitting in my garage for the day it dies, however.

DBL_TKE · Posted: Fri Sep 23, 2011 8:01 am Post subject:

Twilightoptics · Posted: Fri Sep 23, 2011 10:33 am Post subject:

The cases in a T5 are kinda weak. So if you torque arm wasn't held stable it could have been putting a weird load on the mainshaft, and so when you go to shift into 4th which is direct drive, the mainshaft line wasn't straight so it would grind. Same thing happens when the bellhousing is mis-aligned.

That's why alot of people including myself and Rodney, relocate the torque arm to a beefier cross member, so it's not loading the trans weird. Especially with higher HP.

T5 is only rated at 250ft/lb, but I think that is easily increased when the torque arm isn't there. There is a reason they last behind higher HP Mustangs better.

Quasi-Traction · Posted: Sat Sep 24, 2011 4:10 pm Post subject:

Quasi-Traction · Posted: Sat Sep 24, 2011 4:16 pm Post subject: