drive shaft help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

rigon4 · 02-28-2009, 11:54 AM

Ok i think the drive shaft is to long in my 85 short step. It has a 502 with a th400 but its had three trans in it in under 10k it keeps wipping out the tail shaft bushing. I just bought it and i only want to put one trans in it. So does anyone know how long the shaft should be??

1984 swb chevy · 02-28-2009, 06:44 PM

I dont know how long it should be but I do know that your yoke should be out of the seal about an inch. If it is to long the yoke will be against the seal. if it is to short it will leak fluid under hard acceleration. I hope this helps

Rosscup · 02-28-2009, 09:50 PM

i have a 77 short box 4x4 with a TH350 and a NP208 and its drive line is 43.25 inches long but thats a 4x4 so maybe that will give you a ball park

rigon4 · 03-01-2009, 04:15 AM

with the truck on the lift i had a 1/4 inch to slide the yoke in to get to drop out the rear u joint so thats why i think its to long

*78 Chevyrado* · 03-01-2009, 04:55 AM

I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.

grinch4om · 03-01-2009, 08:39 AM

seat the yoke all the way in, pull out 1-1.5 inches, then you can look at how close the rear joint is to the saddles on the rear end...support the truck with jack stands on the suspension when you do this

rigon4 · 03-01-2009, 10:49 AM

the local drive shaft shop wants a measurement from seal to center of u joint with it on the ground. I dropped the trans pan and its junk there is chunks of aluminum.

Damien · 03-01-2009, 06:40 PM

QUOTE=78 Chevyrado;3173015]I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.[/QUOTE]

The drive shaft is too long. I'm sure you just typed it wrong.

I would crawl under the truck and measure the way your shop wants. That is the only way you can be 100% sure you have the right lenth driveshaft.

rigon4 · 03-01-2009, 07:30 PM

did gm make a short box with a big block and a th400 with a one piece drive shaft if so what year?

Cherub · 03-02-2009, 10:30 AM

+1 on getting the shop a correct measurment.

02-28-2009, 11:54 AM	#1
rigon4 Registered User Join Date: Mar 2006 Location: east syracuse ny Posts: 371	drive shaft help Ok i think the drive shaft is to long in my 85 short step. It has a 502 with a th400 but its had three trans in it in under 10k it keeps wipping out the tail shaft bushing. I just bought it and i only want to put one trans in it. So does anyone know how long the shaft should be?? __________________ 1981 K-5 Blazer 2wd 1985 C-10 Short step 1988 C-10 Suburban

02-28-2009, 06:44 PM	#2
1984 swb chevy Registered User Join Date: Nov 2007 Location: New Jersey Posts: 466	Re: drive shaft help I dont know how long it should be but I do know that your yoke should be out of the seal about an inch. If it is to long the yoke will be against the seal. if it is to short it will leak fluid under hard acceleration. I hope this helps __________________ 2010 Tahoe 1984 C10 2005 Harley FLH 1941 Willys Pickup (will never get it done) not for sale

02-28-2009, 09:50 PM	#3
Rosscup Registered User Join Date: Nov 2008 Location: Richland Wa Posts: 1	Re: drive shaft help i have a 77 short box 4x4 with a TH350 and a NP208 and its drive line is 43.25 inches long but thats a 4x4 so maybe that will give you a ball park

03-01-2009, 04:15 AM	#4
rigon4 Registered User Join Date: Mar 2006 Location: east syracuse ny Posts: 371	Re: drive shaft help with the truck on the lift i had a 1/4 inch to slide the yoke in to get to drop out the rear u joint so thats why i think its to long __________________ 1981 K-5 Blazer 2wd 1985 C-10 Short step 1988 C-10 Suburban

03-01-2009, 04:55 AM	#5
78 Chevyrado Account Suspended Join Date: Dec 2007 Location: Unnapreciative, Trollville Posts: 2,079	Re: drive shaft help I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.

03-01-2009, 08:39 AM	#6
grinch4om dang its hot Join Date: Nov 2006 Location: frankfort kentucky Posts: 1,349	Re: drive shaft help seat the yoke all the way in, pull out 1-1.5 inches, then you can look at how close the rear joint is to the saddles on the rear end...support the truck with jack stands on the suspension when you do this

03-01-2009, 10:49 AM	#7
rigon4 Registered User Join Date: Mar 2006 Location: east syracuse ny Posts: 371	Re: drive shaft help the local drive shaft shop wants a measurement from seal to center of u joint with it on the ground. I dropped the trans pan and its junk there is chunks of aluminum. __________________ 1981 K-5 Blazer 2wd 1985 C-10 Short step 1988 C-10 Suburban

03-01-2009, 06:40 PM	#8
Damien Registered User Join Date: Mar 2007 Location: Farmington, MN Posts: 928	Re: drive shaft help QUOTE=78 Chevyrado;3173015]I'm not sure how much, but from what you say it is too short. 1/4 inch is not enough. I'd think it would be like 1-1.5 inches or so, correct me if i'm wrong guys.[/QUOTE] The drive shaft is too long. I'm sure you just typed it wrong. I would crawl under the truck and measure the way your shop wants. That is the only way you can be 100% sure you have the right lenth driveshaft. __________________ I can still count my vehicles on two... wait three hands.

03-01-2009, 07:30 PM	#9
rigon4 Registered User Join Date: Mar 2006 Location: east syracuse ny Posts: 371	Re: drive shaft help did gm make a short box with a big block and a th400 with a one piece drive shaft if so what year? __________________ 1981 K-5 Blazer 2wd 1985 C-10 Short step 1988 C-10 Suburban

03-02-2009, 10:30 AM	#10
Cherub Registered User Join Date: Feb 2008 Location: Houston Posts: 970	Re: drive shaft help +1 on getting the shop a correct measurment.



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