Drivetrain Resonance and other possibilities? 1st gens blowing gearboxes

[gtlegacy]

mean deal and stronger

[Drunkenmonkey]

yeah the local guys give us really good deals got a 230mm sti clutch doubt it had been used $100

[Jase]

 boostin said:

Sorry guys, but I did go through all the 'normal' possibilities before I arrived at this, I just don't think its anything simple, and it still doesnt explain the way the vibrations build and subside in a wave...

This is interesting. On a V8SC a fairly common failure is caused by the 2-piece driveshaft being assembled out of phase. It's easy to do since the centre bearing is near-solid mounted in the chassis and is a 6-bolt ball type CV joint. You bolt the front half to the rear half, but it lines up every 60deg. We always had letters punched in things and lined them up, then the helpful volunteers couldn't bugger it up (much). The result is a small bind every half turn - try putting two univerals from socket sets between 3 extensions and then trying again with one 90deg out.

Obviously the yoke that goes in the back of a Subaru gearbox is splined, and it won't matter how this is indexed.

But, the propshaft bolts together in the middle - can this be assembled 90deg out? (180deg out won't matter)

How it bolts to the rear diff won't make a difference either, but I recall a rectangular bolt pattern on the flange and am now wondering why this is...

Jase.

[edit fixed quote]

[Wiretap]

The flange cannot be assembled 90 degrees out as it is off-square, its actually a rectangular bolt pattern...

[Guest boostcut]

the flange has a rectangular bolt pattern as the yoke at the diff flange end has the two bits for the UJ hanging off it. its just the way its made.