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Discussion Starter · #1 ·
So lately I noticed when I let my foot off the gas and nothing on the brake but just slowing down with the weight of the truck there sounds like a rotational bumps or grinding(bump bump bump bump rapidly) coming from the rear somewhere so I removed the tailgate and it still does it any thoughts or tests y'all got for me to help me find it out or narrow it down atleast and it won't do it the hole time like that once I step on the brakes it goes away... Haven't been under it yet to check it out... 93 d250 lwb club cab le 269xxx
 

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Discussion Starter · #3 ·
Alright and I went and got under it and was able to move the driveshaft around with some pressure but wasn't able to move it much is it okay for the carrier bearing to have that much slack?
 

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It's mounted in rubber so it will have some movement. How about the "U" joints, block the wheels and put in neutral and check them.

Also if there are teeth broken on the ring and pinion it will make noise.
 

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Discussion Starter · #5 ·
10-4! And I know it's not the ring and pinion teeth because 2 weeks ago I popped the diff cover and changed the fluid and examined everything
 

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Check diff fluid level.
 

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Take the truck for a 5 mile drive. Then crawl under it and touch each U-joint. If any feel warm or hot. Replace them.

Checking them for slack a lot of times will not find a bad U-joint. They could be rusted up or needle groves worn into the crosses.
 

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The giveaway here is the noise goes away when you step on the brake. Time to pull the drums and have a look. May just be a rust ridge on the drum or broken hardware.

Loose lug nuts are possible too, especially on a dually.
 

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Definitely u-joints. If you haven't replaced them in a couple years, just do it to rule them out. Easy and cheap to do and they do go bad, so might as well get it done. I would much rather change that than start with my diff and that nasty 80/90 that was just changed
 

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does it do it in any gear? what about in neutral or with the clutch in?

a bad U joint will also often show up as a a clunk when getting on and off the throttle.. The frequency of the noise is a good indicator too... at cruising speeds the driveshaft (and thus U joints and pinion gear) turn at about 3000 RPM, or close to 50 times a second.. that would sound like a growl... issues involving the wheels and ring gear will be rotating at about 6-10 times per second, that would be more of a clunk or repetitive thudding
 
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