I just had another thought...Is it possible for the T-case damper and the Crank Damper to get Out of Phase and set up a vibration? Probably not...
If it were me, I think the first thing I would do is make DAMN sure the harmonic balancer on the engine is in good shape. They can wear out...I might actually call these guys.
http://www.atiracing.com/products/dampers/
They already make a tunable harmonic balancer. No need to reinvent the wheel.
Then, I'd start looking at the T-case damper. Make sure its in good shape. As far as how to "fix" the issue...Still not sure if adding weight is the right answer. It might be a matter of allowing more movement, so you need more rubber.
Something that has been bugging me. You guys are finding that you're getting the vibs after a regear. When you regear, you're increasing engine speed, right? Then you come back and say turning off OD makes the problem go away...Which probably increases RPM yet again. How come these Vibs don't happen at stock RPM? That is slow...and in my mind, it should be present, if its present at the low RPM after a re-gear. I realize this isn't making much sense...I'll need to edit later and try to clean up the language.
It must be entirely related to driveshaft RPM if that is the case.
Another Theory. Does anyone know what the OD switch actually does? Does it put the transmission in Third Gear, or does it just prevent the Torque converter from Locking out. If its preventing the Converter from locking out, THAT is the real answer. You've now added a giant viscous coupler into the system and allowed for the vibrations to be absorbed by ATF, essentially.
If it were me, I think the first thing I would do is make DAMN sure the harmonic balancer on the engine is in good shape. They can wear out...I might actually call these guys.
http://www.atiracing.com/products/dampers/
They already make a tunable harmonic balancer. No need to reinvent the wheel.
Then, I'd start looking at the T-case damper. Make sure its in good shape. As far as how to "fix" the issue...Still not sure if adding weight is the right answer. It might be a matter of allowing more movement, so you need more rubber.
Something that has been bugging me. You guys are finding that you're getting the vibs after a regear. When you regear, you're increasing engine speed, right? Then you come back and say turning off OD makes the problem go away...Which probably increases RPM yet again. How come these Vibs don't happen at stock RPM? That is slow...and in my mind, it should be present, if its present at the low RPM after a re-gear. I realize this isn't making much sense...I'll need to edit later and try to clean up the language.
It must be entirely related to driveshaft RPM if that is the case.
Another Theory. Does anyone know what the OD switch actually does? Does it put the transmission in Third Gear, or does it just prevent the Torque converter from Locking out. If its preventing the Converter from locking out, THAT is the real answer. You've now added a giant viscous coupler into the system and allowed for the vibrations to be absorbed by ATF, essentially.