2 piece driveshaft conversion to a 1? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

SnS C10 · 06-02-2009, 12:35 PM

on my 73 c10 with 454 bbc it originally came with the two piece driveshaft. since i lowered the rear im having problems with the pinion angle. it looks to me if i had a single driveshaft this problem would be eliminated. does this sound right? is it ok to put a single driveshaft with the th400 and 454? is the only thing i would have to do is remove the carrier bearing support and bolt in the new driveshaft?

kris's66lwb · 06-02-2009, 01:04 PM

yea its fine i like the 1 peice better all you have to do is the carrier bering removal and you shuld be golden you migt still need to shim your rear end

SnS C10 · 06-02-2009, 01:05 PM

will a driveshaft for a th350 fit in a th400 as far as splines go?

SnS C10 · 06-02-2009, 01:08 PM

also will the length of the driveshaft for a th350 and a th400 be different assuming the differentials are the same

Keith Seymore · 06-02-2009, 02:42 PM

Does your trans currently have a "fixed yoke"? You have to have some "slip" in the system somewhere to take up suspension jounce and I think that currently takes place in the center support bearing.

Other than that you should be ok.

The reason the factory had a two piece drive shaft in the first place is because they didn't want you to exceed the "prop shaft critical speed", that is, the drive shaft rpm at which it starts to bend and swing like a jump rope. Since that's a function of length and shaft rpm the two piece shaft takes care of the critical speed concern (trading it for an increase in cost, complexity and part count).

As long as you choose or create the right shaft (material, diameter and rpm) it should not be an issue.

K

Driveway Dreams · 06-02-2009, 04:00 PM

Wow, what an explanation. Thank you Keith. I always wondered why we had those 2 piece shafts.

Wild83C10 · 06-02-2009, 07:25 PM

Depending on how low you are, the driveline angles will always be tough with a one piece driveshaft.

SnS C10 · 06-02-2009, 07:42 PM

here are a few pictures so you guys can see the drastic angle of the driveshaft. this is three leafs on either side and thats the only modification. im going to add one leaf and see if that will correct this.

ElGracho · 06-02-2009, 09:53 PM

Why not just lower the carrier bearing?

SnS C10 · 06-03-2009, 01:25 AM

i would need to raise the carrier bearing to fix the angle. im going to add one leaf back in tomorrow to see if it helps. i will post pictures

heavychevy79 · 06-03-2009, 01:37 AM

I'd say don't raise it up, but it looks like you're ridin on the bumpstops anyway.
I don't think I've seen you're truck before, can you post some pics of it.

bharrison1 · 05-30-2010, 01:55 PM

just saw this .did you raise your carrier bearing
?did it help?

boatpuller · 05-30-2010, 07:31 PM

cheapest and easiest way to go........ is cut the original carrier bearing perch out and weld a flat plate in...... then bolt the bearing too it.(raising) it.i did this about 4-5 years ago and never had a problem.here's a pic of how it look's.

OleBlue79 · 05-31-2010, 12:14 AM

Quote:

Originally Posted by Shaun23a11en

will a driveshaft for a th350 fit in a th400 as far as splines go?

No. The output shaft on the 400 is larger in diameter. You can buy u-joints that are made with 400 ears on one side and 350 ears on the other side. So you can mix and match shafts and yokes and rear ends. As for the driveshaft lengths, the 400 transmissions are normally longer than the 350s even if the 350 has the 9 inch tailshaft.
Hope this helps.

westofb · 05-31-2010, 01:21 AM

Quote:

Originally Posted by Shaun23a11en

will a driveshaft for a th350 fit in a th400 as far as splines go?

No, the 400 has a much larger in diameter tailshaft!

06-02-2009, 12:35 PM	#1
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	2 piece driveshaft conversion to a 1? on my 73 c10 with 454 bbc it originally came with the two piece driveshaft. since i lowered the rear im having problems with the pinion angle. it looks to me if i had a single driveshaft this problem would be eliminated. does this sound right? is it ok to put a single driveshaft with the th400 and 454? is the only thing i would have to do is remove the carrier bearing support and bolt in the new driveshaft?

06-02-2009, 01:04 PM	#2
kris's66lwb resident wrencher Join Date: Dec 2006 Location: ramona california Posts: 720	Re: 2 piece driveshaft conversion to a 1? yea its fine i like the 1 peice better all you have to do is the carrier bering removal and you shuld be golden you migt still need to shim your rear end

06-02-2009, 01:05 PM	#3
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	Re: 2 piece driveshaft conversion to a 1? will a driveshaft for a th350 fit in a th400 as far as splines go?

06-02-2009, 01:08 PM	#4
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	Re: 2 piece driveshaft conversion to a 1? also will the length of the driveshaft for a th350 and a th400 be different assuming the differentials are the same

06-02-2009, 02:42 PM	#5
Keith Seymore Registered User Join Date: May 2009 Location: Motor City Posts: 9,229	Re: 2 piece driveshaft conversion to a 1? Does your trans currently have a "fixed yoke"? You have to have some "slip" in the system somewhere to take up suspension jounce and I think that currently takes place in the center support bearing. Other than that you should be ok. The reason the factory had a two piece drive shaft in the first place is because they didn't want you to exceed the "prop shaft critical speed", that is, the drive shaft rpm at which it starts to bend and swing like a jump rope. Since that's a function of length and shaft rpm the two piece shaft takes care of the critical speed concern (trading it for an increase in cost, complexity and part count). As long as you choose or create the right shaft (material, diameter and rpm) it should not be an issue. K __________________ Chevrolet Flint Assembly 1979-1986 GM Full Size Truck Engineering 1986 - 2019 Intro from an Old Assembly Guy: http://67-72chevytrucks.com/vboard/s...d.php?t=342926 My Pontiac story: http://forums.maxperformanceinc.com/...d.php?t=560524 Chevelle intro: http://www.superchevy.com/features/s...hevy-chevelle/ Last edited by Keith Seymore; 06-02-2009 at 02:43 PM.

06-02-2009, 04:00 PM	#6
Driveway Dreams I have car A.D.D. Join Date: Feb 2009 Location: Greeley, Northern Colorado Posts: 4,147	Re: 2 piece driveshaft conversion to a 1? Wow, what an explanation. Thank you Keith. I always wondered why we had those 2 piece shafts. __________________ -Gerald Building vehicles in memory of the first "car guy" I ever knew, my Grandpa. Bob Dunham 1935-2009. Rest in peace. 61 GMC Suburban SOLD The 86 build thread SOLD Are you a Colorado member?Click here.

06-02-2009, 07:25 PM	#7
Wild83C10 Registered User Join Date: May 2002 Location: NJ Posts: 910	Re: 2 piece driveshaft conversion to a 1? Depending on how low you are, the driveline angles will always be tough with a one piece driveshaft. __________________ 83 C10 Stepside (SOLD, it was a blast!) 383 MASS-FLO EFI/TKO II 600/3.90 Posi 10 bolt S475 and C4 DM running, fine tuning turbo= Douchebag Racing: Runs Fine all the Time

06-02-2009, 07:42 PM	#8
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	Re: 2 piece driveshaft conversion to a 1? here are a few pictures so you guys can see the drastic angle of the driveshaft. this is three leafs on either side and thats the only modification. im going to add one leaf and see if that will correct this. Attached Images

06-02-2009, 09:53 PM	#9
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,553	Re: 2 piece driveshaft conversion to a 1? Why not just lower the carrier bearing? __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

06-03-2009, 01:25 AM	#10
SnS C10 Registered User Join Date: Jul 2004 Location: Lomita, Ca Posts: 1,225	Re: 2 piece driveshaft conversion to a 1? i would need to raise the carrier bearing to fix the angle. im going to add one leaf back in tomorrow to see if it helps. i will post pictures

06-03-2009, 01:37 AM	#11
heavychevy79 Cheyenne Super Join Date: Nov 2008 Location: Dallas Texas Posts: 545	Re: 2 piece driveshaft conversion to a 1? I'd say don't raise it up, but it looks like you're ridin on the bumpstops anyway. I don't think I've seen you're truck before, can you post some pics of it.

05-30-2010, 01:55 PM	#12
bharrison1 Registered User Join Date: Jan 2010 Location: haysville,kansas Posts: 524	Re: 2 piece driveshaft conversion to a 1? just saw this .did you raise your carrier bearing ?did it help?

05-30-2010, 07:31 PM	#13
boatpuller Registered User Join Date: Sep 2005 Location: Sun City West, Az Posts: 3,822	Re: 2 piece driveshaft conversion to a 1? cheapest and easiest way to go........ is cut the original carrier bearing perch out and weld a flat plate in...... then bolt the bearing too it.(raising) it.i did this about 4-5 years ago and never had a problem.here's a pic of how it look's. Attached Images __________________ " Never look up a dead dogs butt."



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.