bad vibration

[philo_beddoe]

Surprised i couldent find some old posts on this.  2wd c10, starting to notice a pulsating vibration at about 45-50 mph.  Feel it right through the seats, not the steering column.  Most likely u joints?? How do you check or test them?

[85ckaz]

I replaced the transmission mount in my K20 to eliminate the same issue. To check U joints just push on the drive shaft and you should have no movement.  I would also check the pinion gear bearings/ rear diff yoke for movement. They should be tight. If there is slop in anything it needs to be repaired/ replaced.     

[philo_beddoe]

I'm on it! Thanks!

[philo_beddoe]

New tires and factory rims, but i'll check the weights anyway.  It is not "shuddering" like a bad unbalanced wheel, more of a steady vibrate, hardly pulsating i guess, seems to smooth out near 60 mph.  I tried to move driveshaft, tight as a drum. 

[philo_beddoe]

....oh and yes, one piece shaft,  as far as being a new problem.,, we'll im just now noticing.  I guess i'll let it go for now.  My mechanic is a chevy guy, (i only use him when a garage is needed),  im getting new exh manifolds put on soon, i'll have him take a look.

[philo_beddoe]

Not sure what you mean "out of phase"

[philo_beddoe]

That makes good sense., but i have a one piece shaft.

[philo_beddoe]

....or does it matter in terms of speaking out of phase?

[philo_beddoe]

I will take a look.  It seem to let up when i let off the gas. Does this make sense?

[Irish_Alley]

Yes. I know with my crew cab I had a vibration. I replaced the carrier bearing and my shaft was out of phase fixed both them and the vibration under throttle went away.

[philo_beddoe]

Carrier bearing? Ok, where is it and what does it look like?  I have not delved into that area too much.

[Captkaos]

The carrier bearing will be in the driveshaft.

[philo_beddoe]

Ok, will have a look, thanks.

[Irish_Alley]

Carrier bearing won't be found on your truck. Only 2+ piece drive shafts. It keeps the driveshaft in line. There's a physical limit to how long/thick a driveshaft can be. So they have to split it up in a couple different sections. Fist section will have the driveshaft bolted to the transmission or transfer case. Then a few feet down the carrier bearing attaches to the frame to keep it in line then you have male splines on the end of the first shaft and a female slip yoke drive shaft that will bolt to the rear

[philo_beddoe]

Ok, appreciate the feedback. Maybe it's the flux capacitor...lol.   I will get under there and check correct phase first, check ujoints again, etc.