2 or 1 Piece driveshaft why???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**texassquarebodies** · 06-04-2010, 09:19 PM

Why did GM use 1 piece and 2 piece driveshafts in long beds??? Is one stronger than the other? I never new why?

cableguy0 · 06-04-2010, 10:51 PM

Its all about driveshaft length and critical mass. At a certain speed the driveshaft will vibrate. The speed lowers with the length of the shaft. Generally in a long bed your better off with a two piece that has a slip yoke in the rear shaft. it allows full suspension movement and will reduce the risk of bad stuff happening due to vibrations.

**texassquarebodies** · 06-05-2010, 12:16 AM

I am just wondering why GM did a 1 or a 2 piece drive shaft on a long bed.

*87 chevy silverado* · 06-05-2010, 01:21 AM

i saw a short bed a the junk yard a few month ago that had a two peice

SBTork · 06-05-2010, 01:42 AM

Quote:

Originally Posted by 87 chevy silverado

i saw a short bed a the junk yard a few month ago that had a two peice

I can confirm that. The frame for my project was from an 85 shortbed and it also had a two piece shaft, I also thought that was very odd.

**78 Big10 454** · 06-05-2010, 01:47 AM

My Big 10 SWB has a factory two-piece driveshaft.

79gmcc15 · 06-05-2010, 02:19 AM

Their was a post not that long ago that Keith said why. I just can't think of it.

Edit, I did a search and didn't find what I was looking for. so maybe I was imagining things lol.

Copytech · 06-05-2010, 08:25 AM

Quote:

Originally Posted by 79gmcc15

Their was a post not that long ago that Keith said why. I just can't think of it.

Edit, I did a search and didn't find what I was looking for. so maybe I was imagining things lol.

It is this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=346688

**texassquarebodies** · 06-05-2010, 10:35 AM

Thanks...I was just curious.

boatpuller · 06-05-2010, 12:19 PM

yup,when i first got mine.i thought it was kinda rare.not really that rare at all in a short box.mine was a diesel.it does cause poroblems when you lower them.you get some funky angles.

Pyrotechnic · 06-05-2010, 04:04 PM

I have a one piece in my long bed (the light duty trucks came with them) and at around 100+ MPH I get a pretty bad vibration, and i'm pretty sure it's the drive shaft whipping.

Now that it's due for some new u joints, I'm looking at having the original 2 piece shaft redone and balanced with new u joints and a carrier bearing. 2 short shafts are much stronger than 1 long shaft. I just used the 1 piece because I already had it, and it was freshly redone with new u joints and balanced so I thought I'd give it a try.

06-04-2010, 09:19 PM	#1
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	2 or 1 Piece driveshaft why???? Why did GM use 1 piece and 2 piece driveshafts in long beds??? Is one stronger than the other? I never new why? __________________ Tony Kee Texas Square Bodies

06-04-2010, 10:51 PM	#2
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,948	Re: 2 or 1 Piece driveshaft why???? Its all about driveshaft length and critical mass. At a certain speed the driveshaft will vibrate. The speed lowers with the length of the shaft. Generally in a long bed your better off with a two piece that has a slip yoke in the rear shaft. it allows full suspension movement and will reduce the risk of bad stuff happening due to vibrations. __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

06-05-2010, 12:16 AM	#3
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	Re: 2 or 1 Piece driveshaft why???? I am just wondering why GM did a 1 or a 2 piece drive shaft on a long bed. __________________ Tony Kee Texas Square Bodies

06-05-2010, 01:21 AM	#4
87 chevy silverado Account Suspended Join Date: Apr 2009 Location: lexington South Carolina Posts: 2,124	Re: 2 or 1 Piece driveshaft why???? i saw a short bed a the junk yard a few month ago that had a two peice

06-05-2010, 01:47 AM	#6
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 839	Re: 2 or 1 Piece driveshaft why???? My Big 10 SWB has a factory two-piece driveshaft. Last edited by 78 Big10 454; 06-05-2010 at 01:48 AM.

06-05-2010, 02:19 AM	#7
79gmcc15 Gettin It One Pice At A Time Join Date: Oct 2004 Location: everett, washington Posts: 2,688	Re: 2 or 1 Piece driveshaft why???? Their was a post not that long ago that Keith said why. I just can't think of it. Edit, I did a search and didn't find what I was looking for. so maybe I was imagining things lol. __________________ RIP ELJAY Work In Progress 1979 GMC C1500 Trailering Special. Getting the truck done, one piece at a time. “You can tell a lot about a fellow’s character by his way of eating jellybeans.”Ronald Reagan “I don’t know the key to success but I know the key to failure is trying to please everybody.” Bill Cosby Last edited by 79gmcc15; 06-05-2010 at 05:04 AM.

06-05-2010, 10:35 AM	#9
texassquarebodies Truck Nut Join Date: Jun 2007 Location: Wills Point, Texas Posts: 407	Re: 2 or 1 Piece driveshaft why???? Thanks...I was just curious. __________________ Tony Kee Texas Square Bodies

06-05-2010, 12:19 PM	#10
boatpuller Registered User Join Date: Sep 2005 Location: Sun City West, Az Posts: 3,822	Re: 2 or 1 Piece driveshaft why???? yup,when i first got mine.i thought it was kinda rare.not really that rare at all in a short box.mine was a diesel.it does cause poroblems when you lower them.you get some funky angles. __________________ " Never look up a dead dogs butt."

06-05-2010, 04:04 PM	#11
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: 2 or 1 Piece driveshaft why???? I have a one piece in my long bed (the light duty trucks came with them) and at around 100+ MPH I get a pretty bad vibration, and i'm pretty sure it's the drive shaft whipping. Now that it's due for some new u joints, I'm looking at having the original 2 piece shaft redone and balanced with new u joints and a carrier bearing. 2 short shafts are much stronger than 1 long shaft. I just used the 1 piece because I already had it, and it was freshly redone with new u joints and balanced so I thought I'd give it a try. __________________ 1977 GMC Sierra Grande Last edited by Pyrotechnic; 06-05-2010 at 04:05 PM.

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