Wobble/Vibration Under Acceleration Between 25-45mph

[JohnBravo]

Hello all,

I've noticed a vibration during acceleration that's been hard to explain...almost feels like I'm not getting full torque off the line because there is "slack" in the driveline. I described it to my uncle, and after wiggling the driveshaft around we've determined that it could be this item with the yellow arrow. Near the red arrow the driveshaft is stable and does not wobble at all (and it appears that this has been replaced recently), but around the yellow arrow it has a slight amount of play. We cannot rule out U-Joints at this time, but if I replace this bearing/support, I'll probably replace a couple U-Joints.

What is the yellow-arrow item called? I wasn't sure if it's a carrier bearing, or if there is a different name for it...I'm new to this, and not knowing makes it difficult to search specifically.

At first I thought the wobble/vibration might be wheels/tires. The issue persists after a new set of tires mounted and balanced. Transmission fluid has been changed, rear diff fluid changed, all clean (whoever had my truck before was awesome on maintenance). I'm open to suggestions also as far as additional parts to inspect - hoping to replace all 4 shocks later next week.

Thank you for your time.
JB

2000 K2500 350ci 4l80e 3.73 8600gvwr

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[RPF207]

that's called a carrier bearing and they do fail just like anything else. Funny thing is, any vibration from rear driveling or tire problems I've ever had show up around 40-50 mph. And if it's a driveshaft problem most of the time it's worse when applying throttle

 

[98vortec]

how you replace carrier bearing?

 

[JohnBravo]

I believe you have to remove the driveshaft to replace the carrier bearing. Sorry I cannot elaborate as I've never done it.

Random question regarding U-Joints - is there a consensus on Moog vs. Spicer for our trucks? General Bing search is mixed as far as which are preferred. I was leaning toward solid (sealed, non-greaseable) Spicer u-joints, but AAP coupons would help keep costs down if Moog u-joints are decent. If anyone with a similar truck to mine (see signature) has the correct part numbers, that'd be appreciated also ;-)

 

[joep88cheyenne]

To remove it, it starts like any drive shaft. You remove the rear bearing brackets at the diff. Then unbolt the bearing and pull shaft out of the tranny. Then this is the next step... there is a bolt the holds the two pieces together that has to be removed. I had one on a 69 c10 long bed, but was not able to figure out how to remove it so just did front and rear bearings and reinstalled. But it did not slap or pop or have noise. YMMV and more ways to get info now than in 74.

Have you checked the engine and trans mounts? They can add to vibrations also.