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

62 short step · 04-27-2007, 12:22 PM

Thinking about putting an auto in my 61 4x4, it has the sm420 with divorced t-221. How short can the jackshaft be?

1969k10stepside · 04-27-2007, 01:44 PM

Ok,what do you mean by jackshaft?Must be a different name for the same thing.Probably know what you are talking about,just dont know what your definition of a jackshaft is

**CUSTOM/10** · 04-27-2007, 01:55 PM

I believe he's talking about the shaft from the trany to the devorced transfer case.

62 short step · 04-27-2007, 02:07 PM

Quote:

Originally Posted by CUSTOM/10

I believe he's talking about the shaft from the trany to the devorced transfer case.

Yep thats it.

62 short step · 04-28-2007, 02:20 PM

ttt

1969 GMC · 04-28-2007, 03:27 PM

There are a few people over on Pirate 4x4 running a divorced t-case right up against the tranny with just one u joint, no shaft at all. I would say that is doable, as long as they are braced together, so there is no driveline flex.

Preferably, you'd want to have the two ujoints and some splines to allow for flexing of the drivetrain. So as short as you can make that combo, I'd say.

62 short step · 04-28-2007, 04:17 PM

Thanks for the info! I have heard at least a foot long, but I wanted to see if any of you had done this. Thanks for the replys, Jeremy.

04-27-2007, 12:22 PM	#1
62 short step Senior Member Join Date: Aug 2005 Location: Greenwell Springs, Louisiana Posts: 2,882	Jack shaft Thinking about putting an auto in my 61 4x4, it has the sm420 with divorced t-221. How short can the jackshaft be?

04-27-2007, 01:44 PM	#2
1969k10stepside Registered User Join Date: Mar 2006 Location: USA Posts: 21,019	Re: Jack shaft Ok,what do you mean by jackshaft?Must be a different name for the same thing.Probably know what you are talking about,just dont know what your definition of a jackshaft is Last edited by 1969k10stepside; 04-27-2007 at 01:44 PM.

04-27-2007, 01:55 PM	#3
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,854	Re: Jack shaft I believe he's talking about the shaft from the trany to the devorced transfer case. __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859

04-28-2007, 02:20 PM	#5
62 short step Senior Member Join Date: Aug 2005 Location: Greenwell Springs, Louisiana Posts: 2,882	Re: Jack shaft ttt

04-28-2007, 03:27 PM	#6
1969 GMC Registered User Join Date: Feb 2003 Location: The Rubber City Posts: 5,498	Re: Jack shaft There are a few people over on Pirate 4x4 running a divorced t-case right up against the tranny with just one u joint, no shaft at all. I would say that is doable, as long as they are braced together, so there is no driveline flex. Preferably, you'd want to have the two ujoints and some splines to allow for flexing of the drivetrain. So as short as you can make that combo, I'd say. __________________ 1969 GMC K2500 1996 Honda Accord 2007 Kawasaki KLR 650

04-28-2007, 04:17 PM	#7
62 short step Senior Member Join Date: Aug 2005 Location: Greenwell Springs, Louisiana Posts: 2,882	Re: Jack shaft Thanks for the info! I have heard at least a foot long, but I wanted to see if any of you had done this. Thanks for the replys, Jeremy.



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