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Discussion Starter · #1 · (Edited)
I am no mechanic, so I was hoping the supra community could help me figure this out.

I bought the Supra 2 years ago and it sat for a year @ Dynamic Autosports in Lake Forest California. Finally picked it up from Dynamic July 2008. Shipped it to Hawaii and finished the build. (that's a huge long thread by itself). From Jan 2008 - July 2008 - Dynamic pretty much replaced everything... Rebuilt motor @ Hiros in CA, Stroker kit, new fuel, new aem, new turbo, new BL Auto...

Car is stroked 3.4 w/ Garrett T04Z w/BL making ~ 500hp.

Monday, we drove the car to the dyno (about 5 miles away) , strapped it down to the dyno and on the 1st pass, about 6,500 rpms the trans / drive shaft broke and spit its guts out.

the dyno run : http://s724.photobucket.com/albums/ww241/anakaoka2/Dyno/?action=view&current=BeeBreak.jpg
- It broke @ ~ 6,500 rpm

has anyone seen this happen before?

Took the trans apart. Everything was free spinning up until we got to the main shaft at the back of the trans.

the problem - to try to find the problem, we took the tranmission apart and all parts were free spining except the main drive shaft at the rear of the case.

http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01576.jpg
http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01577.jpg
http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01578.jpg
http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01579.jpg

Valve Body looks ok

http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01580.jpg

other photos:
Tunnel damange and bent driveshaft - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01538.jpg
Cracked Trans - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01539.jpg
Bent shaft - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01540.jpg
cracked & bent shaft - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01541.jpg
Mid pipe damage - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01542.jpg
4" Midpipe - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01543.jpg
Drive shaft bent and broken - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01544.jpg
Drive shaft twist - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01545.jpg
Cut Trans cooler line - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01546.jpg
Drive shaft twist - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01547.jpg
Drive shaft twist - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01548.jpg
Inside trans - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01549.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01550.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01551.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01552.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01554.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01555.jpg
Cluth plates - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01558.jpg
flywheel - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01559.jpg
drive shaft twist - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01560.jpg
parts - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01561.jpg
HKS torque converter - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01562.jpg
Cracked Trans Case - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01563.jpg
Cracked Trans Case - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01564.jpg
Cracked Trans Case - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01565.jpg
Cracked Trans Case - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01566.jpg
ring looks warped - http://i209.photobucket.com/albums/bb209/anakaoka/blown trans/DSC01567.jpg


I am just trying to figure out why this happened....
 

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Every single driveshaft I have seen that broke/twisted did so because it was either bent or dented.

Was there any noise when you drove the car to the dyno session?

I would inspect the floor of the car and look to see if whatever equipment that was used to transport or move the car touched the floor which might give you evidence.
 

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Discussion Starter · #3 ·
Every single driveshaft I have seen that broke/twisted did so because it was either bent or dented.

Was there any noise when you drove the car to the dyno session?

I would inspect the floor of the car and look to see if whatever equipment that was used to transport or move the car touched the floor which might give you evidence.
no, there was no vibrations before it went.

the shaft was in there for about a month. drove ~ 150 miles on it, no vibrations detected.

launched on it once, no problems.

can you tell anything by the direction in which the metal is bent? looks like the wheels were still spinning and the trans stopped, so the shaft got bent in that direction.

I am so grateful and blessed it didn't happen on the freeway.
 

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I'm drawing a blank here since the rear mainshaft of the tranny getting serious runout at high speed could cause the driveshaft to fail but I'm leaning toward the driveshaft failure causing the tranny damage.

It may have had a stress crack that caused the driveshaft to break enough for it to twist but stay connected (for a couple of revolutions at least) while pivoting on the point that is still connected.

This would cause the driveshaft to impart huge forces on the tranny before it ultimately came apart.

Big enough forces to bend the output shaft.

I really don't see any other way the output shaft could bend like that unless it failed the way I described.
 

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I thought that for a minute but then remembered that the driveshaft beat itself against the tunnel as the rear end and wheels spun down which folded the broken ends of the driveshaft that direction.

Very tough call and still not sure of my hypothesis.

Just glad nobody got hurt.
 
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