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u-joint explodes at 70 miles an hour

Kain

Kain

3/4 ton status
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Was driving back from levelland checking on a class i want to take.
Crusing at 70 no vibration no noise, just kaput
The front joint in the rear shaft decided to give up the ghost. i thought the rear blew or the transfer case by the way the truck shook and the noise it made, heard it over the exhaust and the stereo.

took out the rear shaft and drove it home in 4 high.
took the rear cover off and checked out the diff and no meatel parts no extra play in the gears no damage. so i guess the joint just failed.

Ps what kind of rear is this with the goofy clockwork peices in it?

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you can see the dents in the exhaust on both pipes but no tears or holes.
and the dent in the fram, not to mention it ripped the ebrake cable out. glad just a section of cable and some goofy clips.
 
You got lucky. A u joint explosion at 70 can do some serious damage. I had that same u joint (t case end of rear shaft) explode on my 76 but thank god the shaft didn't actually drop until I was off the highway. I drove about 20 miles down the highway. No vibes or anything funny and then I stopped for gas and as I was rolling away from the pump after filling up I heard this huge clunk and then the truck wouldn't move. I freaked. Thought I had blew something big, then look under the truck and the driveshaft is laying on the ground. I drove home in 4 high as well.
 
Kain said:
Was driving back from levelland checking on a class i want to take.
Crusing at 70 no vibration no noise, just kaput
The front joint in the rear shaft decided to give up the ghost. i thought the rear blew or the transfer case by the way the truck shook and the noise it made, heard it over the exhaust and the stereo.

took out the rear shaft and drove it home in 4 high.
took the rear cover off and checked out the diff and no meatel parts no extra play in the gears no damage. so i guess the joint just failed.

Ps what kind of rear is this with the goofy clockwork peices in it?
Click to expand...


Holy cow man glad you're safe. U joint failures at speed can be baaaaad news.

As for the gov-loc not sure how yours works in the dirt but the one in my '72 works really well, as good if not better than the one in my '04 CC.

Now, I'm off to find a new front shaft for the jimmy.:eek1:
 
76k5blazer
ya i did, i had top pull the yoke of the transfer case, what do i torque that nut at?
ive looked in the book mi have and asked some mechanics and they geuss at what it should be.

i have to get fluid, 2 u-joints,and a strap kit. to get it going. i need an ebrake cable and the two clips that atatch it to the rear.

woodchk502
thanks me too, i thought the transfer case went the way the truck bucked.
I wonder if the u-joint caps had something to do with it.
I bought the ones with the grease fitting in the cap and i found peices of the cap that grenaded where the grease fitting is.

if this thing keeps eating u-joints once a year i have to change them.
I will have to think about getting a bigger joint and a new shaft
 
Another 10 MPH and you could have put this in the "Can you drive 80 MPH +" thread.:D

Your real lucky to say the least....What makes this even worst....It was the front joint that let go. Heard about this catapulting the vehicles into the air when the shaft sticks into the ground.
 
I had a u-joint explode on a 78 GMC when I was going around 55mph. It did all manner of damage to the truck because the front of the driveshaft dropped and dug into the road. It launched the rear up about 6" or so and tore up the rear axle. Bent the shaft like a drinking straw and I'm pretty sure I soiled my armor.:eek1:
 
I had something like that happen to me with my old '76 K5. I had just pulled off the freeway after about 100 miles of interstate. I was accelerating out of the intersection and that same ujoint let go. I was hard on the gas and was running a 402 big bock at the time, so it was under some torque. When it broke, the driveshaft smacked the bottom of the truck so hard that it made the center console jump. :eek1: Fortuneatly, I coasted to a stop directly across the street from an autozone. :haha:
 
As for that nut that holds the yoke on to the t case. Think of it like an axle yoke nut. When you change a pinion seal you mark the threads where then nut is, take the nut off, remove the yoke and seal, Install new seal, put yoke back on and tighten the nut back to your mark you made, then go a little bit past it to get it nice and snug. Same thing with the yoke on the t case. Now if you didn't mark the threads when you removed your yoke then I would just tighten it till its snug, main thing is don't overtorque. Hope that helps
 
Burbdood 74 said:
I had a u-joint explode on a 78 GMC when I was going around 55mph. It did all manner of damage to the truck because the front of the driveshaft dropped and dug into the road. It launched the rear up about 6" or so and tore up the rear axle. Bent the shaft like a drinking straw and I'm pretty sure I soiled my armor.:eek1:
Click to expand...

I had the driveshaft on my '56 Chevy 3200 pickup decide to drop out when I went over some railroad tracks a bit too fast one day---the driveshaft evidently wasn't the correct one,someone stuffed one a few inches shorter in it before I got the truck I guess..

---it came out of the slip yoke at the tranny,dropped onto the railroad tracks,got caught,and the rear of the truck did a 3 foot high leap off the ground,and came crashing down hard...it bounced about 3 times as I rolled to a stop,and it happened about 200 feet from an auto body shop--the guys were all outside taking a smoke break,and I heard them all whoop and applaud..then one of them pipes up and says "that was teats man,do it again !"...talk about embarrasing..:blush:...

The manager of the body shop let me park the truck in their lot till I could come back and get it fixed somehow..the guys helped me push it..
I think my shorts got soiled too,I was glad I was only going about 35 when I went over the RR tracks..

The driveshaft actually tore off at the rear yoke and rolled to the side of the street--kinked in half and all twisted up...:doah:

I found a driveshaft out of another similar truck,a '55 GMC,at a small "junkyard" about 2 miles up the street,for 20 bucks I was very lucky--I also bought a spare 3 speed tranny from the guy for another 25 bucks..both were already out of the truck,sitting on the bench seat too!...

I wished I could have bought at least one of the half dozen trucks he had like mine--most were in better shape cab wise than mine,thought it was a shame they were just put out to pasture to rot and get cannibalized..I later found out that guy was about the only place around that kept any trucks that old too...
 
Glad you're even here to post this! I've seen a couple fatal u joint failures, front dropped and caught like Diesel said but catapulted the car into an end over end disaster.
Your thread caught my attention because I noticed a steady 'thump thump thump' in the floorboard the other day like a busted belt but don't feel it in the brake pedal or steering wheel as much as the floor. I'm headed out after my coffee to put the new front u joint in my 'burban, the rear one I changed when I swapped in the 12 bolt last summer.
 
ya i think my gardian angle needs a brake. i have everything ready to put ujoints in as soon as i can afford them allong with fluid for the rear diff.
 
this brings to light all the safty equipment we install like cages / 5 point harness / and other stuff.

the fact no one realy installs a drive shaft loop on our trucks is little crazy I think . we are asking a LOT more of our u-joints at the steeper angles we put them at and never think about it .

yes its rare but we should put at least a hoop up by the tcase end for this simple fact .

and just buy good quality u-joints over cheepy parts store name china chinsy crap .
 
well the crossmember played catch and wont let it hit , but if you guys dont have one get a saftey loop, dont want to die cause a u-joint failed......
 
well crap, i took the old u-joints out of the drive shaft today and one of the caps had needle beerings inside laying down instead of standing up. it was on the joint that fail so i think i found the cause.

There is only one thing i hate worse than diff fluid and that is u-joints.
i think ill have em put in only 40 bucks to have them installed
 
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