Does your driveshaft run uphill or downhill to the rear?
If you really wanna get anel about setting angles, you check it with the pilot sitting in the cockpit.

 

Under Vibration Diagnosis and Correction, 2002 Chevrolet Camaro | Camaro, Firebird (VIN F) Service Manual | Document ID: 751544 Driveline Working Angles Measurement (One-Piece)",
GM SI says:

"Compare the front and rear working angles. The angles should be equal to each other within ½ degree to provide effective cancellation of the U-joints.

If the difference between the front and rear working angles exceeds ½ degree, the angles require adjustment. Refer to Driveline Working Angles Adjustment .

If the working angles are equal to zero, the angles require adjustment. 0 degree working angles will cause premature U-joint wear due to lack of rotation of the U-joint bearings. Refer to Driveline Working Angles Adjustment .

If the working angles exceed 4 degrees, the angles require adjustment. Refer to Driveline Working Angles Adjustment . "

 

Stock rear LCAs and my Moog 1LE bushing upgrade did not improve or degrade the vibration issue further. Torque Arm bushing looks fine (only one, in the front) and is still original I believe -- might be worth replacing? What about the welding subframe connectors when the suspension was not at rest? Koni SA shocks on all fours, Strano sways, stock SS springs.

 

This is what I was taught, The whole pinion angle thing is not something we normally adjust in stock cars. I think if you are fabricating you set the pinion angle to make sure the working angle is not over stressed under launch. Once you get the pinion angle the way you want then adjust the trans to get the working angles better then 1/2 deg. I have fixed vibrations in a lot of cars and I never changed a pinion angle.

Working angles of zero causing the U-joint to be damaged is pretty well known even by younger mechanics. The 1/2 deg compared working angles is less known. The 4 deg max will never be an issue in a Camaro, that is more of a truck thing. At 4 degs the Camaro driveshaft would be either digging in the road or spinning in the back seat

Now if you really want to have some fun figure it out when you have 4 sections of drive shaft, 8 U-joints and 2 carrier bearing and a vibration under load after the utility bed is install. That a work order that makes you want to just punch out and go home.

Have you checked your angles? all you need is a angle gage, The new digital ones are nice but I just use my choke angle gage, (ha I am showing my age again). I like it because it is small enough I do not have to use a socket for a spacer.

 

My trans mount was replaced with an OEM style one a few years back and is still in good shape, motor mounts were replaced with OEM ones last year. This vibrations existed before both mount changes, however.

 

Will have to check, and plan to return to Suburban Driveline to discuss the pinion angle, etc. and see the measurements, which were not noted on my work order.

 

I have another theory, after talking to a auto parts guy who used to be GM Service Manger, and talking with another transmission repair specialist that this could be related to the torque converter clutch getting too hot, creating a noise/vibration like going over rumble strips, which is one way I could describe my issue.

Dr. Tranny Instant Shudder Fixx

 

Its a thought, however you said you were getting the shudder with the old and the new converter. Have you tried driving with the shifter in third and not putting it in fourth/overdrive/lockup?

 

True, I had it with both old and new converters.

I will try that. It was suggested today that it could be a 3/4 solenoid -- the screen could be clogged -- however those were replaced during the build...

 

Well, the Shudder fix did nothing... Next idea?