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- - bad monday (https://67-72chevytrucks.com/vboard/showthread.php?t=703168)

Tried my truck at wot for the first time today. All went well until tranny hit third, that's when the rear universal twisted out of the yoke. Torked the tranny so hard the case cracked, some pieces came off, driveshaft broke off tranny tail. Blew off the flexplate dust cover and took some teeth off the flex plate. Only hope the engine and rear are ok. Anyone ever heard of this severe result of losing a rear universal joint, and steps for preventing in the future. Universals were new, straps were new. I'm puzzled!

What engine/trans? Stock or modified?

Sounds like the perfect time to upgrade to an overdrive trans. You need the trans and driveshaft anyway.

Are you sure the driveshaft went first? Or did trans have spectacular failure, lock up, and take u-joint out? Not saying that's what happened, but that's a whole lot of damage to the trans caused by a u-joint.

383 stroker
700R4 tranny
2000 rpm stall converter
3:73 rear gears with locker

Heard and have witnessed and has happened to me before. People forget about what connect the front to rear and all the power/force that is being generated through the drive shaft. I myself with my new motor and trans and everything else built up have not gone WOT yet. Why? My stock drive shaft and weak ass u joints. So I dropped the coin and ordered a Dynotech 3.5" aluminum drive shaft with the Spicer 1350 u joints. It cost $575 shipped I had to pay tax. Comes with forged Spicer slip yoke also. And I ordered a forged pinon yoke also. The driveshaft setup is rated for 1000 HP and 900 TRQ. Just my opinion and what has happened to me in the past and what I would suggest you to do when you get it fixed.

My setup is...
385 stroker
PTC TH350
3500 stall
3.73 Limited Slip

I would think a u-joint would break before falling out of the yoke. Maybe it wasn't seated all the way? Definitely a bad Monday.

It may have been the space aliens messing with you.
They won't leave me alone.
Sounds like somebody slipped some made in China parts into your truck when you were not looking.

Quote:

Originally Posted by bbj3316 (Post 7548352)

Anyone ever heard of this severe result of losing a rear universal joint, and steps for preventing in the future. Universals were new, straps were new. I'm puzzled!

Lost a rear u-joint cruising down the Interstate, all new u-joint and straps. Don't know if it was a defective part or shaft. It all looked good during assembly. Big bang, shrapnel through the floor, smoke in the cab, people weaving around trying to avoid the drive shaft remnant that shot out from under the truck. It gets real interesting real quick. Output shaft was bent close to a 45* and the trans case was shredded. Found what was left of the shaft way down a ditch past the breakdown lane. It could have been a broken u-bolt, bad joint, etc - the yoke looked fine and measured out correctly. Never had that happen again but I get a little nervy with strap style u-joints - like the 14 bolt strap. Some companies make a girdled strap and there are u-bolt style conversion yokes.

I welded up the shrapnel holes in the trans tunnel and put a new transmission and spare drive shaft in it. Sold it about a year later and the new owner (friend) never had any problems. I still have no idea what gave way.