I've only ever stripped a planet in my racecar. It weighs between 3360-3600 depending on ballast to run index (9.25), or flat out in the high 8 second zone. So yes I would say you had bad luck with the planetary. Still many cars using the low roller clutch (what many call the sprag) as the only means of holding the drum. Which is also how it is held in the factory transmission when D is selected. I build many hot rod and Race 727's. Usually 15-20 units a year. Never had a customer lose a low roller or a drum. Obviously correct driving technique should be used. If there has been drivetrain failure in 1st gear, the trans shoud be taken apart and checked. For what it's worth the worst beat up low roller I've repaired was in a car that had low band apply. It was shuddering pretty bad in 1st gear. I'd like to know the story on how the failure occured in post #30. It appears to be a bolt in low roller. It obiviously didn't stop any carnage. Though that failure ruined the case, if it had a good drum that was the end of any further explosion.
Doug
Thanks. My planet wasn't totally stripped, just a few splines fell out when I removed it. It was the factory 4-pinion version. Caught it when upgrading the transmission for the new bigger stroker. That is when I upgraded the sprag and drum. I wasn't planning to upgrade the planetary gear as that was an unexpected hit to the wallet.
The picture looks like the A&A Super Sprag? Hard to tell as I didn't zoom in on the photo, but has the 6-bolt holes and looks like 16 roller ramps? Just don't want readers to confuse the different "Bolt-in" sprags. There are factory style 12 element sprags that are modified to "bolt-in", but they are intended to just be a repair part for a bad case. The Performance sprags I believe have 16 rollers vs. the factory 12. The story on the blown up sprag would be interesting. maybe accidently shifted into reverse at speed?
Had a guy strip out a factory pressed in sprag trying to rock his truck out of snow by slamming the trans between forward and reverse.
Also, had a shift kit with the modification that allows first gear select at any speed. Please don't do that modification, Over-reved the engine and bent valves when down-shifting, intending to select second and grabbed first.
There seems to be some confusion on burnouts too. Many say to do burnout in second gear, but that was the instructions for a manual valve body with no low bad apply.
With a factory type forward pattern valve body, selecting second gear is the same as drive, it just keeps from shifting into third, but still starts of in low without the rear bad applied.
Selecting 1st gear (manual low) will apply the rear band which is how you want to start the burn out and then shift into second gear.
Seems this got off topic.