First Generation Firebird-L Mailing List ......................................................................... I took a look at the dimensions of the TH400 compared to the other automatic options and it's about 5" longer as best I can tell without knowing the specific tailshafts used on each application. I would assume that it's even more then 5" longer then the manual transmission option. the longer the transmission, the shorter the driveshaft would be. the shorter the driveshaft, the greater the angle's at the ends of the driveshaft, assuming all the axle and engine centerlines are at the same angle for teh various options. So with the greater angle for the TH400 cars that extra angle might have created enough extra torsonal load to take care of the alleged vibration. That would be why only the TH400 cars has the in-phase yokes and the others had the slightly out of phase yokes.
________________________________ From: S Sterchi <[email protected]> To: [email protected] Sent: Thursday, February 12, 2009 10:56:34 PM Subject: RE: [FGF] Driveshaft First Generation Firebird-L Mailing List ......................................................................... Lots of talk on this issue on the Camaro threads but no definitive answer regarding why. I think my driveshaft guy was right that this was GM's attempt to resolve a harmonic vibration issue with 1st Gen FB/Camaros. Some on the site seem to think it might have been for getting these cars into Trans Am racing but I think that's pretty far fetched. http://www.camaros.org/forum/index.php?topic=914.0;all Also confirmed on a different site re: diff offset 1/2" towards P-side. Looks like I will be doing some adjusting since I set my shifter to center like a dumb ass when it should have been 1/2" towards P-side (Tremec shifter sits dead center). I gave the tranny a big push but had to take out a motor mount to get the necessary play. Got the transmission just about right (still 1/16" to 1/8" off) but now the motor mnt bolt won't go back in. I'll be getting my crane out and possibly loosening up the motor mount plates to get the adjustment. Total pain in the arse. Sheen > My recollection is that the stock is in phase. Out of phase will definately > be hard on the u-joints. > > >> > .........................................................................> > > I'm having a driveshaft built for my Tremec/81'TA rearend set up using a new > 3" shaft and all Spicer parts. My driveshaft guy wants to build it in-phase, > i.e. differential weld-yolk and trans weld-yolk on the same plane, as opposed > to out of phase. My original, or at least the one I had on my car, is about > 30* out of phase. Is this the way they came stock? He explained to me that > there are a few 60's cars that came with out of phase driveshafts to counter > a harmonic problem with the car, but, building it in-phase is the way to go > for strength and u-joint durability. Any thoughts?> > Thanks,> SHeen _________________________________________________________________ More than messages–check out the rest of the Windows Live™. http://www.microsoft.com/windows/windowslive/ ------------------------------------------------------------------------ Submissions to Firebird-L: <[email protected]> Unsubscribe from Firebird-L: <[email protected]> Help: <http://FirstGenFirebird.org/firebird/Firebird-L.html> Classifieds: <http://FirstGenFirebird.org/ubb/> Owner Pictures: <http://FirstGenFirebird.org/show/> Donations: <http://FirstGenFirebird.org/store/cart.mv?999999> FGF Merchandise: <http://FirstGenFirebird.org/store> ------------------------------------------------------------------------ Submissions to Firebird-L: <[email protected]> Unsubscribe from Firebird-L: <[email protected]> Help: <http://FirstGenFirebird.org/firebird/Firebird-L.html> Classifieds: <http://FirstGenFirebird.org/ubb/> Owner Pictures: <http://FirstGenFirebird.org/show/> Donations: <http://FirstGenFirebird.org/store/cart.mv?999999> FGF Merchandise: <http://FirstGenFirebird.org/store>
