something just fell off?!?!?!?!

[Zeronight]

so i just got my 97 k1500 ext 5.7 back from the trans shop. i was driving down the hwy enjoying how it could shift between ALL the gears again and i got up to around 95 or so and i heard a loud bang. i looked in the rear view and saw something long and black fly away from my truck. my first thought was "crap i just blew out my drive shaft" but that wasent the case. it didn't cause any issues for any other drivers (none around) or any thing but when i got off the hwy and looked under the truck the only thing that looked different was the rear drive shaft, it looked cleaner and newer for some reason. was/ is there a cover of some kind on the rear driveshaft that i just lost due to speed? it has not seemed to affect drive ability, in fact it seems smoother as previously around 75-80mph i would get vibrations i dont see as strongly as now. i drove back 2 times and couldn't find what came off. please tell me im not losing my mind.
thanks

 

[TheAutumnWind]

so i just got my 97 k1500 ext 5.7 back from the trans shop. i was driving down the hwy enjoying how it could shift between ALL the gears again and i got up to around 95 or so and i heard a loud bang. i looked in the rear view and saw something long and black fly away from my truck. my first thought was "crap i just blew out my drive shaft" but that wasent the case. it didn't cause any issues for any other drivers (none around) or any thing but when i got off the hwy and looked under the truck the only thing that looked different was the rear drive shaft, it looked cleaner and newer for some reason. was/ is there a cover of some kind on the rear driveshaft that i just lost due to speed? it has not seemed to affect drive ability, in fact it seems smoother as previously around 75-80mph i would get vibrations i dont see as strongly as now. i drove back 2 times and couldn't find what came off. please tell me im not losing my mind.
thanks

Did they leave a magnetic flash light under there? I left one attached to a friends inner fender well once.

Or some other tool. I would definitely recommend that you take it back and have them look at it to confirm no damage was done.

 

[Supercharged111]

Aluminum driveshafts had a black carbon cover, sounds like yours freed itself. If the truck doesn't vibrate, I wouldn't sweat it. If it does, get the shaft balanced and you'll be good to go. If there are any chunks still sticking, pick them and the glue off. If you have the shop look at it, leave the 95mph part out of it.

 

[df2x4]

Aluminum driveshafts had a black carbon cover, sounds like yours freed itself.

Not all of the aluminum ones got the covers (at least my C1500 didn't), but this was my first thought as well.

 

[Eveready]

What about the tube that leads from the spare tire winch to near the back bumper. I don't know how easily it could come loose but it might fit your description.

 

[454cid]

If you lost the carbon fiber on your drive shaft, I'd say that driveshaft is now compromised. The carbon fiber wasn't put there for looks.

 

[Supercharged111]

If you lost the carbon fiber on your drive shaft, I'd say that driveshaft is now compromised. The carbon fiber wasn't put there for looks.

Mine got messed up when a u-joint suddenly freed itself on my 88, so we ripped it all off and I never noticed anything different. I imagine there is a reason, but I doubt any of us know beyond speculation.

 

[Zeronight]

Thank you all for your replys. like i said i just needed some reassurance. im going to lean towards Supercharged111 being correct.

 

[98chevy2500SS]

It does sound like the cover let loose. I don't know what it's purpose is, but most people remove it anyway since it seems to collect salt and other nasty stuff when it gets old. Not sure if my 97 had it or not, didn't have the cover when I bought it.

 

[alpinecrick]

According to the GM mechanic I bought my 97 from, the composite cover on the aluminum driveshafts were intended to reduce the flex in the shaft as the axle moved up and down at a high cycle rate when going over bumps at speed. Note: Flex is not the same as torsional “twisting” of the shaft under load.

And maybe more important according to the mechanic, the cover also protected the shaft from flying rock/gravel dings. I suspect even a moderate ding could unbalance the shaft.

I question the flexing part because the only cover I’ve seen off of the drive shaft appeared to be only glued in various places, not fully glued all around the shaft. I would think to be effective the cover would have to be fully glued to help reduce flexing.