Bucking and Noise when accelerating

I have a 2012 Taco, 4dr, Automatic, 6cyl, with a 5 ft bed. Recently I began to notice a thud and a bucking action when accelerating either from a complete stop or a slow roll. The truck may buck two or three times coupled with a rear end thud then afterwards it runs fine. It does not happen each time I begin to move but seems to be happening more often now. Before I bring it in for service I would like your advice on what you feel the cause may be. Thank You

billo

 

Do you hear/feel it more toward the front or rear?

 

Put your truck on some jackstands with the engine off jerk your tires north and south your uca bushing might be bad as far as the rear I have no clue

 

my first thoughts:

check torque on all bolts on leaf springs and rear lugnuts.

condition or level of oil in differential?

condition of ujoints on drive shaft?

condition of bearing at middle of driveshaft?

 

My first thought is driveshaft. Once it's spinning it'll balance better with speed.

 

It sounds like it is coming from the rear. My first thought would be a Stuck Brake shoe since I have Drums in the rear. Hope that's all it is.

billo

 

After more Bucking Sessions, some without a Clunk, I finally took the truck back to the dealer. They put it on a lift, test drove it with me along for the ride and of course, no bucking or clunking. Since they could not duplicate the problem they sent me on my way stating if it continues bring it back. I have purchased 5 Toyotas from the dealer and all serviced there. I was not charged for the inspection. However it keeps happening, say once every 300 miles or so. My fear is that I will get stuck somewhere on a highway and that makes me fearful of taking any long trips. My question is, Is this symptom a known fault? Is there a TSB or some type of Recall? Thank you for your assistance.

billo

 

After several bucking sessions the problem has now gotten to the point of a Loud Humming noise when driving +55-60mph. Just yesterday while exiting a Highway and having to keep the wheels turned as the exit ramp was circular, it felt as if my right wheel was wobbling and was about to fall off. I pulled over and checked the bolts, etc and all was fine. I have stock wheels and same type of tires that came with the truck. It makes no noise if turned while stopped. Car is driven at 35-40mph feels fine. It still bucks once in a while but this loud hum and funny feeling makes driving a worry. Last time the dealer had it they found nothing wrong. Any suggestions as I am fearful of driving the truck. Thank You

billo

 

Take it back to the dealer as they suggested.

 

Sub'd

 

Just a thought ....

Did you pull the rear drums to check the brakes???

After you get the humming - pull it over and feel the center of the wheel to see if it's too hot and you have a brake dragging or a separated / wedged shoe as you indicated.

Let us know what you eventually find ...