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Thump in my drivetrain at stop?

sled_dog

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I know this is a little bit of a ghost that I can't see just tracking down but worth a shot. Recently when I come to a complete stop at a stop light, I hear and feel the slightest little thump. Kind of like when something slides forward in your bed and hits the front of it. But its much more faint and not nearly as violent. I don't notice it if I'm just going like a few mph and then stop but if I'm doing like 25 and slowly stop when I fully stop it happens. I almost think its something like the torque converter not unlocking but I really doubt that. I can't say as far as the engine if it bogs at that point, its too damn quiet with that stock exhaust and I don't really notice anything by the RPMs but it idles at 600 RPMs.
 
I had that problem when my carrier bearings in the 14 had worn enough to create alot of backlash. When I would come to a stop it would thump. Pulled the cover and I had about .025" of backlash, I tightened it up to about .007" and it was quiet again.
 
I would look at the rear backlash and other drivetrian slop. I have experinced that type of feeling with bad ujoints. My extended cab truck has a two piece driveshaft and the center bearing is bad and creates movement in the driveline (mostly in the form of a vibration at takeoff). Good luck.
 
slip joint according to other people on this site. I have the same problem and can't say that i;ve corrected it yet but i will. that is if you have the slip yoke coming out of the transfer case type driveline
 
I didn't catch what year your truck was but my daily driver is an 01 x-cab 4x4. I had the same problem around 18k, right about then I got a letter from Chevy on a recall on the slip yokes. They say that the clunk thump what ever you want to call it is because of dissimilar metals binding. It almost felt as though the tranny was jumping in and out. Brought it in and it did fix the problem.... Now with 61k on it once again it has started again, but I know what it is now and it doesn't bother me.... I hope that your problem could be as simple as mine was to cure...
 
I have a '95 2wd with the 4L60E and it does just as you say. It kind of feels like it slips out of gear for about a half second and then right back in, it don't do it on every stop. The truck has 176,000+ miles on it and still going strong so I don't worry about it too much... I was gonna' change the tranny fluid and see if it helps, it has been in there for about 80,000 miles /forums/images/graemlins/shame.gif /forums/images/graemlins/doah.gif
 
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