Something is not good here?

[RJB44]

I took my truck down for an inspection yesterday and as I began driving I noticed a very hard vibration at low acceleration (up to around 25 MPH). I have previously written about a vibration issue I was experiencing, however it seems much harder now. It vibrates to the point the screws for the plastic panel above your head become loose and almost fall out.

Something else I noticed was that when under a load (low acceleration), I would occasionally hear a whining sound from underneath (like somewhere in the drive line). It went away as soon as I took my foot of the gas. It happened twice on the 12 mi round trip from service station to home, once on the way in and once on the way back. I have never heard this noise before, but since it is present with a much harder vibration, I can only assume that there related and something bad will ultimately happen, and soon!

Could this be the transmission starting to go? slipping? I have no smoke, or burning smell, no other indication of a problem. I just don't want to get stranded with the truck.

91 GMC Jimmy


Thanks

 

[British Slave]

have you checked your u joints?

 

[RJB44]

U-Joints

Yes, I know they need to be replaced, but they don't appear to be excessively bad, at least where they look like they are going to blow on me. The whining noise is what concerns me the most. I will replace my u-joints tomorrow.

 

[rufusbooth]

Once a u-joint starts going bad, you don't have much time left. They go downhill in a hurry. If you can feel movement they are done. Get them changed ASAP and make sure you replace them in pairs. If one is going the other is sure to follow.

Once those are changed we can diagnose the whining much easier. while you are under there check the end of the drive-line where it enters the trans and rear end. Make sure the bearings on the yokes are nice and tight.

Cheers,

Rufus

 

[95stroked1500]

one rig i worked on, had a shake like you say. when you gave it gas it would just shake like mad and not accelerate worth a darn. no clang putting it into gear, keeping foot on the brake going from drive to reverse. i crawled underneath and the rear u-joint was shot.

whining.... after the u-joints are replaced then continue to track. could be tranny, transfer case,... rear end. even if the pinion bearings aren't loose, pull the diff cover and use a pry bar to see if you can jimmy the carrier up and down.