U joints

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Sep 1, 2002 | 06:14 PM

hippi97

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Joined: Sep 2001

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From: cohutta usa

U joints

I have a 79 f100 with a 460/C-6 and i`m haveing trouble with rear u-joints. I changed them less than 200 miles ago and the rear ( closest to the pumpkin ) has already got slack. Anyone else had this problem?
If so whats the fix?

Sep 1, 2002 | 08:52 PM

Torque1st

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U joints

You have to have the angle of both ends of the driveshaft the same. I have seen a lot of trucks that have the pumpkin pointed right at the end of the driveshaft and other strange things. Modern U-Joints should last 100,000 miles.

Sep 2, 2002 | 08:04 AM

garypettengill

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Joined: Jul 2002

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From: USA

U joints

I've got a '77 short bed 4x4 and the most rear u-joint has always been a bone of contention. 200 mi. is way to fast to get sloppy but I normally had to change mine about once a year when I was using the truck daily and towing things. I changed the joints in the fwd. end of the shaft about 5 years ago, just because they hadn't been changed in 15 years. It has a double croyden on the front of the shaft. Pay for the best joints you can. Lift kits and big tires aggravate the problem.
Gary

Sep 3, 2002 | 09:42 AM

Scot

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From: 15 miles west of Venus

U joints

You may well be frying the u-joints with the hp/torque the mighty 460 is making. My '75 highboy would go 10K or so between ujoints on the entire driveline.

Sep 3, 2002 | 12:27 PM

Franklin2

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From: Virginia

U joints

Here's an article on the subject. Sounds like the driveshaft angle cannot be very much to last a long time.

http://www.drivetrain.com/driveline_angle_problem.html

Sep 3, 2002 | 03:38 PM

Torque1st

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U joints

That is a good article. There is one paragraph that is not real clear that could take some more explanation or a drawing. But everything else is great!

All bearings have a service life that is detewrmined by the load and rpm's. In a U-joint the bearings themselves don't revolve but they do have a frequency of oscillation that translates into the speed of rollers moving over a surface.

Properly set up and maintained, even the U-joints on a 460 should last 50,000 miles. Abuse like shock loading will shorten that life. Larger U-joints can sometimes be obtained by selecting the proper input and output shaft yokes.

Sep 6, 2002 | 02:05 PM

dfisher1

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Joined: Jul 2001

Posts: 1,613

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From: Gainesville, FL

U joints

All,
Let's not get to carried away here.
Your driveshaft is either too straight or too crooked.
Which is it?
Your not factory, are you?
GM offset their motors 8mm to the passenger side to get the U-joints some offset. Such fine adjustments seem unrealistic.
Tell us what you've done and we'll tell you what to do next.
KingFisher