what is causing this
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Freshman User
Joined: Dec 2003
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thumps at takeoff
Anyone know what this is? Every once in a while when I take off from a stop I feel three or four bumps. They aren’t very loud, but they feel like something is slipping. It feels like it is coming from the rear. It also will thump loudly if I let off of the gas and then step back on it. When I am barely giving it gas while going down the highway it has a small grinding or vibrating feeling, just when I am barely pressing on the gas though. Something tells me these are all related, and I feel like something is about to go out on it. If anyone has any advice it would be greatly appreciated
Last edited by whoop09; Feb 13, 2004 at 03:31 PM.
Elder User
Joined: Dec 2003
Posts: 655
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From: Miami
Could be "U" joints starting to go. Put the truck in park and go under and grab the drive shaft and try to turn it, and see how much play you have and if you here the noise. You want to hope it is that, and not the alternative, the rear end.
She Ain't Revved Ti'll The Rods Are Thrown!
Al
She Ain't Revved Ti'll The Rods Are Thrown!
Al
Senior User
Joined: Nov 2003
Posts: 258
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From: Camden County, NC
I agree with the above reply. Please do a search on here and you should find out more info. You will get better, more responses if you title your threads like "Noise "thump" in rear or under" in stead of the general "What is this noise" type. Not trying to be jerk here just trying to be helpful. Good luck...
Lead Driver
Joined: Jul 2003
Posts: 7,404
Likes: 52
From: Wheatland, Mo
It sounds like it is the double cardon joint on the rear drive shaft. I had to replace the 2 u-joints in the yoke for the same problem. The yoke is towards the front end of the rear shaft...and while your at it...replace the far back u-joint as well.
Elder User
Joined: Apr 2002
Posts: 813
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From: NJ
what billy bob said, and definately change all three u joints. be carefull when you do the double cardon joint it has many small needle bearings, unless they are totally worn away.
you can buy a complete drive shaft from advance for about 200.00$ then you just have to remove and replace the drive shaft.
the u joints are about 13.00$ each and if the cardon joint is bad i think the rebuild kit is another 40.00$
you can buy a complete drive shaft from advance for about 200.00$ then you just have to remove and replace the drive shaft.
the u joints are about 13.00$ each and if the cardon joint is bad i think the rebuild kit is another 40.00$
Junior User
Joined: Oct 2003
Posts: 52
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Sounds like the backlash in the rearend. If the pinion and ring gear are not meshing correctly this will cause vibration as well as the clunk when you let of the gas. Jack the rear up and turn the drive line back and forth and see how much play you have in the rearend. Just a thought..
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Senior User
Joined: Dec 2002
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From: Temecula
Try greasing the slip joint to, mine was bumping upon take off and greased the slip joint and fixed it
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Freshman User
Joined: Dec 2003
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Thanks for all of the advice y'all. I got under there today and checked to the u-joints. I couldn't find any play in them, but when I looked at the dc joint and the ring in the middle (don't know what it is called) has three cracks in it. Could this be causing the problem?
I will also go ahead and grease the slip joint while at it.
How big a deal is backlash in the rearend from the ring and pinion gear not meshing correctly? Haven't checked that out yet just wondering.
I will also go ahead and grease the slip joint while at it.
How big a deal is backlash in the rearend from the ring and pinion gear not meshing correctly? Haven't checked that out yet just wondering.
5th Wheeling
Joined: Jan 2004
Posts: 31
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If you have an 8.8 differential the ring gear & pinion backlash is nonadjustable, so if the backlash reading is not within specs. then either one or more of the pinion bearings or carrier bearings are bad. You will need four special tools if your going to take the diff. apart, It takes a special tool to hold the pinion flange, a puller to remove the pinion flange, a 0-60 beam type inch pound torque wrench ( ratchet type won’t work ) to read the pinion bearing preload, a dial indicator and mounting base to check backlash and a 0-250 ft.lb. torque wrench to torque the pinion flange nut. Taking the diff. apart and putting it back together isn’t very hard, but getting the pinion preload right is a real pain. If you don’t get the preload exactly right you will wind up with a noisy rear end or a chipped tooth on the ring gear or pinion. Personally I wouldn’t tear into the differential unless I absolutely had to and was absolutely sure I knew what I was getting to.
Senior User
Joined: Dec 2002
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From: fairbanks usa
i had the exact same noise sounded like a ratchet it was the dc joint if you put it in neutral and smack the driveshaft at the joint it will make the same noise. replace the u-joints when you change the dc joint because you need to remove them anyway.