Everyday truck problem

reborn55 · September 05, 2010, 08:51:00 PM

1999 Silverado, extended cab LS, 5.3, 2wd with 90,000 miles has developed intermittent what appears to be drive line vibration. Replaced center bearing and rear ujoint. Tires rotated--problem is that it comes and goes--no rhyme or reason. Drove 50 miles to look at new truck--drove great--coming home vibration came back into play at highway speeds. Give it a little gas to increase speed and it would go away..I know it needs new rear shocks--hit a bump and the rear will dart some times. Was looking at trading it off--got a great deal pending on anew GMC, but would rather keep mine and save the money for my 2 toys. Any ideas where to look or has anyone had any experience with this.

wayne petty · September 05, 2010, 09:23:09 PM

if the shocks are bad on either end... it does not take much out of balance to set the tires bouncing down the road...

got a good friend with good eyes or skills.. who can drive along side at road speeds while you try to get the tires to shake...

signal him with the 4 way flashers while its shaking..

if he can isolate the vibration.. by viewing the tires...

if the front are moving up and down..
shocks... tires out of round.. belt separation.. balance problems

or

wobbling left and right... loose steering linkage.. loose adjustment at the steering box.... worn pitman arm end.. or center link... worn or broken steering coupler for the box to steering column ...

worn steering damper.. if your truck is equipped with one.. i have not looked...

if the rears are bouncing up and down.... tire balance problem.. tires out of round... bad shocks... really bad shocks....

the cheep rear shocks at some parts stores are like 25 bucks each...

reborn55 · September 05, 2010, 09:27:09 PM

Wayne---tires are relatively new and rotating them did not change the feel of the vibration---coming from what I think is the driveline some where. Have had the wife behind me ad next to me and nothing is noticeable.
Thanks

wayne petty · September 05, 2010, 09:37:31 PM

grab the yoke where it sticks into the tail housing of the transmission... with the parking brake on.. tires blocked.... transmission in neutral...

grab the yoke.... see how much vertical play there is in the tail shaft bushing...

i have fixed a LOT of trucks with a slightly worn tail shaft bushing that was causing the rear view mirror to blur at speed...

Crosley.In.AZ · September 06, 2010, 09:43:41 AM

dry U-joint binding up as it gets hot ?

reborn55 · September 22, 2010, 09:15:35 PM

little update--replace u joints and believe it or not--that made teh vibration worse. Used proper u joint tools not the hammer and socket I usually do. Crawled under the truck and watched the driveshaft. real bad bounce at the slip yoke. Don't know how or why it happened. Put 2 hose clamps on the slip joint and vibration is gone---rides like a new one. so I guess I will pull it and get straightened and balanced--if that doesn't work--a friend has the one piece replacement for my truck. Still can't figure why it ahppened.
Thanks

Fat Cat · September 22, 2010, 09:41:42 PM

It is possible that the slip joint is worn too. We see that on off road class 8 trucks alot.

BFS57 · September 24, 2010, 06:23:33 AM

Hello;
They don't make anything like they used to!! Everything is Cheap, Cheap, Cheap, as possible. Given the advent of off shore parts and even replacements are junk!!!

Bruce

Rrumbler · September 24, 2010, 03:39:56 PM

I had pretty much the same problem on my '79 Suburban; finally had the driveshaft rebuilt with a new slip joint and U-joints, and a ballance, and it cleared it up. There was some just barely perceptible side play in the slip joint (rear DS), and it got overlooked for quite a spell.

reborn55 · October 01, 2010, 08:57:19 PM

Another update I sent the driveshaft off to get balanced and they bent the heck out of the flange on the shaft and lost the bolts from the center beariso I had to send it back. Good thing I have a couple of cars. Just love Murphy's Law. thanks all

wayne petty · October 02, 2010, 10:52:24 AM

one thing about drive shafts that get out of balance...

i had a customer with a 79 seville milan... shortened seville made into a convertible... he had driveshaft problems as it was only 3 feet long...

after having a local but expensive drive shaft shop build a new one for him... he took it down for new tires... it has wobbled for years... finally smooth power... when he left the tire shop... it started wobbling again... he did not tell me that the wobbling started after the visit to the tire shop... that took some figuring out what happened...

when it got it to me it was terrible... what happened... the hydraulic lift.. that tilted up from the ground to lift the car enough for tire work had impacted the drive shaft and bent the main tube...

the worst part... after i had the drive shaft shop rebuild the drive shaft again... had to pay again for it... less the second time... he took it back to the tire shop for a tire rotation and to complain about them bending the drive shaft.. so they stuck it back up on the lift to prove it did not bend the drive shaft... bent it again.. that shop still saying that it won't hurt the drive shaft... the are made of steel... they won't bend..