I wonder who could balance my shaft out here in Louisiana...?Anybody?

 

Thats terrible but at least no one was hurt and the rest of the truck is unscathed.

I was at my clubs anual GM vs Ford EFI (kinda) shootout and my buddy has a 98' Formula with a 408 carb setup with a 9" and a Rosler T-350. His first pass in the car in nearly 2yrs of work and his first ever with a T-Brake and the damn driveshaft let go at the U-Joint and wedged itself stuck and blasted his new T-350 to pieces. It literally broke through the trans housing and dropped internals and fluid all over under the car. I think he moved a total of about 2" on that launch. Expensive combo and he relied on the stock steel driveshaft which everyone though would be fine. Sometimes overkill is a good thing

Which is why I had "Lex" installed on my overkill beast lol

 

Well went by to see how bad the damage was. When I grabbed the output shaft of the transmission I could move it up and down about an inch, those little springs that are in there all the way around, about 1/2 of em were gone. Quality. The transmission mount on the transmission had broken off, so it dropped down and was sitting on the frame. Sweet. So I have a couple options. 1) Get a standard core trans with X miles on it and get that in or B) the guy who owns the shop can get me a decent built trans from RPM transmissions (http://www.rpmtransmissions.com/index_015.htm). I've read nothing but good things about them on LS1Tech, and for a couple hundred more, it puts my mind that much more at ease, so I think that's the way to go as it comes out cheaper than the price listed for a brand new 4L60E on partszoneonline.com. Whatcha think?

The thing that's bothering me now is using that link Blown posted earlier, with a 72" driveshaft, 5" in diameter, .080 thick, I'm getting a critical speed of ~6200. So either my 1.5" leveling shackle had more of an effect than one would think, or I just ran into some bad luck. I mean 4100 RPM is waaay lower than 6200?! I will definitely be making sure my angles at the trans and diff are the same. Problem now is getting someone to build a 72" driveshaft taht will do the job(i still want to get dynoed). But that 4100 vs 6200 just bothers me

Here are some pics of the parts. The back part of the driveshaft was brought to the dealer for an oh **** factor.

Extension housing

Part of the driveshaft. That's paint from where it punctured the floorboard in 2 places.

Female end of the DS

Clean break on the weld

more weld

and more

 

Man what a clean break. That sucks man. Glad to see you have access to another trans!
What kind of driveshaft did you decide to go with?

Jim

 

What are the stock ones made from?Just wondering...

 

One-piece shaft= aluminum. Two piece shaft=steel.

Jim

 

sounds like many of us reading this thread shoudl be lookin into drive shafts to avoid this carnage

 

Actually, I'm confident that had I (1) corrected the pinion angle issue after the drop, and (2) balanced my driveshaft upon receipt of the vehicle, I would have had no problems whatsoever.

 

Jim, great question. I'm not sure yet. I know when this happened to TBSS he couldn't find anyone to make a 72" long driveshaft better than GM. I'm going to call around to see what i can find, but like TBSS said, if the angles are good (I'm stull surprised a 1.5" drop shackle would mess that up) and the shaft is high speed balanced, there shouldn't be a problem. But it sure would be nice to have a shaft with more than an .080" thick wall. I guess steel is another option.

Andrew

 

Just a quick update. Went back to the shop today to pull teh interior so I could pound the metal back into place where it punched through the floor. Took a look at teh dyno information again. I was actually running at 5000RPM/124MPH when it let go. Makes me feel better than the 100MPH I originally thought it was. Only was getting 254TQ/207HP out of a Nelson tune. AFR was a little rich though, around 12.3-12.5. Hopefully I can send Allen the info and get updated accordingly.