The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 03-23-2016, 10:25 PM   #1
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Clearance for 1 piece driveshaft on LWB

Just did a tremec trans swap in my 67 long bed. I have to get a new driveshaft and was hoping maybe to go to a one piece. I searched and people have done it, but I don't see anyone saying how much clearance you need between the carrier bearing crossmember and the driveshaft. Or at least how much people have and if the shaft ever hit.

The local driveshaft shop recommended a 3.5" aluminum shaft for my truck. It's lowered and I just installed the CPP crossmember. My measurements say with a 3.5" shaft I would have right about 1/2" clearance. Doesn't seem like enough to me. Really don't want to back up my brand new crossmember.

Shop was worried about the length but did caution me I would need to make sure the driveshaft didn't hit the crossmember as one snack would likely ruin the $500 shaft
Tiger Joe is offline   Reply With Quote
Old 03-23-2016, 11:49 PM   #2
Clavo106
Registered User
 
Join Date: Apr 2015
Location: Yakima, WA
Posts: 362
Re: Clearance for 1 piece driveshaft on LWB

I would think some one with drag racing experience can answer this question since they run safety loops on there drive lines.. the longer the shaft the more flex.. thats the reason for a two piece shaft with a carrier....
Clavo106 is offline   Reply With Quote
Old 03-24-2016, 07:10 AM   #3
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Re: Clearance for 1 piece driveshaft on LWB

I can't edit my post from last night but shop was NOT worried about the length, but cautioned about hitting it off something and ruining it
Tiger Joe is offline   Reply With Quote
Old 03-24-2016, 08:06 AM   #4
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Re: Clearance for 1 piece driveshaft on LWB

doing some math on my notepad at my desk here this morning.

If I only have 1/2" clearance at the carrier bearing cross member (which is just over 1/3 of the way from the trans to the rear tires) that would basically mean my rear end can only move down 1.5" till the shaft hits. doesn't seem like enough to me
Tiger Joe is offline   Reply With Quote
Old 03-24-2016, 08:25 AM   #5
Grumpy old man
Senior Member
 
Grumpy old man's Avatar
 
Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 8,545
Re: Clearance for 1 piece driveshaft on LWB

It's not enough clearance . $500.00 is a lot of $ for a drive shaft . 2 piece shafts were used just for this reason , Clearance! Unless you start making more room ( cutting the crossmember ) your not running a 1 piece shaft . Some parts just aren't made to work together without modification .
Posted via Mobile Device
Grumpy old man is offline   Reply With Quote
Old 03-24-2016, 08:56 AM   #6
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Re: Clearance for 1 piece driveshaft on LWB

yup kinda what I figured not enough room.

I'll probably just have him shorten my stock 2 piece and hope it lasts.

Im running it behind my 600hp 496 BBC.

Edit: ya I wasn't too impressed with the $500 price, BUT he is the closest driveshop to me, less than 15 min away. otherwise I have to drive like an hour.
Tiger Joe is offline   Reply With Quote
Old 03-24-2016, 09:25 AM   #7
Ironangel
Senior Member
 
Ironangel's Avatar
 
Join Date: Feb 2010
Location: Falls City, Nebraska "100 Miles From Nowhere"
Posts: 2,219
Re: Clearance for 1 piece driveshaft on LWB

The reason(s) GM used a two piece drive line are (1) Pinon angle. (2) A two piece drive shaft is stronger and will spin up more rpm before reaching maxium critical speed. They each have their pros and cons but the two piece pro's far outweigh the one piece cons of less weight and rotaing mass. A one piece shaft will deliver more instantainious response, but with more stress to the slip yoke and tail shaft bearing in the transmission as well as the pinon bearing(s) in the differential. For the cost of an aluminum shaft with an aftermarket crossmember, I could buy a case of carrier bearings and never worry about critical speeds or vibrations wiping out a bearing. Your shaft shop is correct to warn againt contact or strikes to the aluminum shaft because one slow hit on a speed bump or a racoon at 70 mph will do it in. Do some research, most all muscle cars and trucks, domestic and foreign, have two piece drive lines.~Ghostrider~
__________________
Michael of the clan Hill,
"Two Seventy Two's"
71 1-ton Dually 350 4-Speed
71 C/50 Grain Truck, 350 Split-Axle 4-Speed
02 3/4 ton Express
14 Indian Chief Vintage
1952 Ford 8N, "Only Ford Allowed On The Property"
"Be American, Buy American"
Ironangel is offline   Reply With Quote
Old 03-24-2016, 09:37 AM   #8
Grumpy old man
Senior Member
 
Grumpy old man's Avatar
 
Join Date: Dec 2013
Location: Gods country East,Tn
Posts: 8,545
most all muscle cars have 2 piece driveshafts ??? Which ones ? I don't remember ANY muscle car using a 2 piece drive shaft with a carrier bearing midline ?
Posted via Mobile Device
Grumpy old man is offline   Reply With Quote
Old 03-24-2016, 10:03 AM   #9
67 chevelle
Registered User
 
67 chevelle's Avatar
 
Join Date: May 2013
Location: WEST PALM FLORIDA
Posts: 1,174
Re: Clearance for 1 piece driveshaft on LWB

I think you just need your stock shaft shortened [don't let it go to your head] , that's what I did with mine , frame cut and stock 4 speed to 2004r , cost me 100 bucks
__________________
68 Long Fleet , ly6 , turbo 350 , 3-5 drop , original paint , front discs
67 Small window , 7 foot bed , tweaked 6.0 LSX 2004R Medium Olive
58 Apache fleet , 235 , offy intake , dual exhaust , 4 on the floor , red/white
69 Long Fleet , Custom , 6.0, 4l60 , AC , Medium Olive
67 chevelle is offline   Reply With Quote
Old 03-24-2016, 04:09 PM   #10
NC_John
Registered User
 
NC_John's Avatar
 
Join Date: Jul 2013
Location: Rockwell, NC
Posts: 1,639
Re: Clearance for 1 piece driveshaft on LWB

Quote:
Originally Posted by Tiger Joe View Post
yup kinda what I figured not enough room.

I'll probably just have him shorten my stock 2 piece and hope it lasts.

Im running it behind my 600hp 496 BBC.
When I put the tremec in my long bed I just had the driveshaft shortened and balanced. Also had these guys

http://www.driveshaftshop.com/

Put solid u-joints in it to make a bit stronger.

I doubt you are hooking up with 600 hp. Mine just spins, even with posi, so at least its easier on parts and I haven't broken anything yet.
__________________
1970 C-10 LWB "Blu"

Instagram (current build pictures) 70_nc_c10
NC_John is offline   Reply With Quote
Old 03-24-2016, 09:28 PM   #11
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Re: Clearance for 1 piece driveshaft on LWB

I've snapped a weak u joint in half on a hard 1-2 shift when the truck hooked. Blew the super T-10 apart twice too. I never broken the actual shaft even at 6500 rpm shifts so I think it will live on.

Two piece is shortened and already installed. Shop said there was slop between the two shafts which he fixed, so I should be good to go.
Tiger Joe is offline   Reply With Quote
Old 03-25-2016, 06:42 AM   #12
NC_John
Registered User
 
NC_John's Avatar
 
Join Date: Jul 2013
Location: Rockwell, NC
Posts: 1,639
Re: Clearance for 1 piece driveshaft on LWB

I remember the guy at the machine shop telling me the two-piece driveshaft was going to be the "fuse" in my setup. My transmission is way overbuilt for my current engine build (had it overbuilt to handle the next few engine stages) and the 12 bolt rear-end should be plenty strong. I have only 350 hp but ought not have any problems until I get some real tires out back instead of the skinny white-line radials.
__________________
1970 C-10 LWB "Blu"

Instagram (current build pictures) 70_nc_c10
NC_John is offline   Reply With Quote
Old 03-25-2016, 08:37 PM   #13
stsalvage
Scrapper 1
 
stsalvage's Avatar
 
Join Date: Jan 2007
Location: Riverside Calif
Posts: 1,649
Re: Clearance for 1 piece driveshaft on LWB

I thought the new DOT law was nothing over 61 or 66 inches.Drive shaft places bare the responsibility if something goes wrong.And most Drive shaft places won't Do it.

You ever seen a drive shaft come undone under a truck i have 1977 1972 longhorn Pogo stick at 55 mph it was not pretty
stsalvage is offline   Reply With Quote
Old 03-25-2016, 08:57 PM   #14
Tiger Joe
Registered User
 
Join Date: Mar 2015
Location: South of Pittsburgh
Posts: 428
Re: Clearance for 1 piece driveshaft on LWB

Shop said 1 piece shaft was not an issue for the length I wanted in 3.5" aluminum. My issue was my clearance to my trailing arm crossmember.

Never heard of any law for driveshaft length. GM puts some pretty long driveshafts on some of the trucks from the factory nowadays.
Tiger Joe is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 08:17 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com