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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 79GMClowboy on July 10, 2009, 02:27:26 pm

Title: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: 79GMClowboy on July 10, 2009, 02:27:26 pm

I took my 2 piece driveshaft out...I was going to swap it with a 1 piece...I have a short bed with a 400 transmission...The 1 piece shaft cam out of a 78 with a 350 trans....I knew the yolk would have to be swapped over to the new shaft....No problem there...It looks like the driveshaft is 2 inches too long..The only different I could see is the yolk on the 400 bolts to the transmission output shaft...It does'nt float...Even if I get a new yolk that still is'nt going to change the fact that the driveshaft is too long....WTH? I cant understand this..The only thing I can figure is its a long tailshaft on the trans....It does not appear to be though...The yolk on the 400 says SPICER...someone help me please...

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: HAULIN IT on July 10, 2009, 03:46:27 pm

You have a mis-match of parts there...You have to have some means of a slip, either in the front (2wd TH350) or middle (2wd TH400) or the rear (some 4x4's). This is needed because as the suspension goes through it's travel up & down, the rear axle moves foreward & backward a little. Hope this helps, Lorne

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: VileZambonie on July 10, 2009, 03:54:40 pm

(http://www.parade.com/export/sites/default/food/recipe-tips/kitchen/images/refimages/eggs/hardcooked.jpg)

Couldn't resist. Look at this shaft....
(http://i6.photobucket.com/albums/y228/Sabaka454/DSC00178.jpg)


That's what you're gonna need or a 2 piece like you had.

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: 79GMClowboy on July 10, 2009, 09:35:11 pm

What if I do this...Get the driveshaft shortened 3 inches and get a yolk that will float on the output shaft...

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: HAULIN IT on July 11, 2009, 02:40:38 pm

If I'm following you correctly...That's fine (& the way I would do it), but you would have to disassemble the transmission & convert it into a "car" output shaft/tail housing. Lorne

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: VileZambonie on July 11, 2009, 06:23:55 pm

Yoke not yolk

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: 79GMClowboy on July 12, 2009, 08:48:27 am

Thanks for the correction...I've been in North Carolina so long that I'm starting to spell and talk like em..
I dont have to swap out the output shaft..I called shaftmasters and they said they counter bore the yoke so it will work in a truck application.....That was the first I've heard of that..He says they get atleast 5 calls a month on the same situation..  www.shaftmasters.com 

Title: Re: WTH? I CANT FIGURE THIS ONE OUT,,,This driveshaft swap is killing me..
Post by: HAULIN IT on July 12, 2009, 12:21:09 pm

So you install a (short?) "car" tail housing & cut off the threaded area of the output shaft? If so, that's kinda nice, it would really make the truck trannys much more desirable for other applications. Lorne