TorqueFlite Burnouts

Duane said
To me those photos and your explanation of the two distinct types of roller clutch failures are one of the best explanations I have seen.
It also explains that even a 904 while not as explosion prone, can still fail the roller clutch and you have a broken transmission.
Low band apply valve bodies and upgraded roller clutches are imho wise purchases for a performance torqueflite of either version. An aftermarket drum with a higher explosion rating is also wise just in case all else fails.
I also re read the exploding torqueflite post and noted that the drum rpm on a failed sprag is engine rpm multiplied by the first gear ratio.
So if your torqueflite has a 2.74 low gear, it is much easier to get the drum to its rpm limit. Most articles I have read claim it is engine rpm multiplied by 2.2

Thanks for the compliment Duane.

You know, it is amazing to me that all of that rotating mass inside an automatic has very little keeping it all aligned and centered. There is the slip yoke at the back (provided the bushing isnt worn and you have proper yoke engagement), the one ball bearing in the tail shaft, the direct drum suppprted by bushings on the back of the stator and the nose of the input supported in the torque converter.....provided your eng to trans alignment is good. I really am amazed that none of this vibrates.

When you load the rolling elememts into the sprag it becomes apparent how much that inner race can move around. If you twist it and push it to one side the rollers will allow if to move way off center. I believe this happens due to case distortion and the internals moving around under torque, and the rollers then jump pockets and the sprag fails...

Just my opinion though.