Broken Transaxle Casing/bellhousing

[bigpatofpa]

First off please check out the pics and thanks in advance.

93 tsi awd manual 6 bolt, 14b, 2.5 o2 housing, 2.5 inch downpipe to muffler no cat. energy suspension motor(3) trans(1) mount inserts. Act 2600 clutch/pressure plate, act lightweight flywheel, oem throwout brg(aftermarket ones are noisy) all new parts installed 8k ago.
I was driving, stopped at a stop sign, first gear pulled away , shift to second and no clutch. it was soft and woulnd't disengage. I thought i had a fluid issue, there were no leaks , had it towed.
I start tearing into it and i see this broken piece of casting between the clutch fork and block, the cutout for fork is intact except for a small crack. I think this was caused after the big chunk broke and weakened the structure.
The case is also cracked at the next bolt ccw, between the 2 serial no. plates. the backing plate behind the flywheel is broken in 2.
see pictures

Engine/trans swapped from a 97,000mi donor. Mounts, clutch and exhaust were installed at this time.
The car has a vibration/ slight shudder around 2.0k til about 2.5k rpm. The vibration really transfers thru body and interior. I read alot of threads about the poly mounts and no cat can amplify the noise. So i wasn't real concerned. Still running balance shafts. I don't beat on her.

I know how how to fix it. I was hoping that somebody might have some insight as to what caused it. I'm not completely convinced that vibration broke the case like that.
Could it be caused by the pivot bolt not being spaced out, stock slave cyl rod?? Maybe a bad casting?? I don't want to fix the parts and not cure the problem.

 

[NeMiZiS]

Wow that looks bad, time for a new tranny.
I would like to know how you did that, with out beating on it.

 

[crusada]

I agree id like to know how with out beating on it or hitting something that nuts dude. I also agree time for a new trans. I honestly dont know what would have caused that. Unless something wasnt tightend down right when it was swapped and it possibly vibrated enough and violet enough that over time it broke it heck i dunno.

 

[bullet99]

The fly wheel and clutch are in one piece? Maybe a bad cast and the heat finely did it in or to much TQ. Are all the mounts tq to spec?

 

[starfish]

I know sometimes when installing a trans if you dont have everything lined up right and you start drawing in the bolts too fast (specially with air tools) you can crack the aluminum casing without noticing it.It then spreads like a windshield crack and before you know it,it shatters in a bunch of pieces.Or its possible your starter was loose or needed shims.Was your starter making any funny sounds

 

[talondave]

Did you have the two dial pins in the block? Not having those installed will cause the trans to twist no matter how tight you have the bolts, resulting in the case craking/ breaking!!

 

[miguelmcv]

Wow.
I would like to know what happen as well.
The GSX That I just Bought, had the Plate Broken as well.
Looking at your broken plate I would say that is my broken plate, (Broke from the same area and the same figure).

Sorry for the Tranny.

 

[bigpatofpa]

Both dowel pins are there. When i installed the tranny she slid right in tight to the block. I don't use air tools on cast or aluminum. Torqued to spec? I didn't use a torque wrench, i did use a fairly short 3/8 wratchet. Definitely not under torqued, good possibility they are over. I have a suspended license, i drive like an old lady. The car was launched once about 1k after the clutch was installed other than that i'm pretty gentle. I do have 2 spares in the garage so dont feel too bad. Ican just swap that part of the case. I just hate fixing something only to have it happen again. Thanks again for the feedback