for the past couple of weeks my truck has been shaking violently. i can't figure out what it is. i need some help, and i'm going to be as thorough as possible here. when i'm driving normally and get up to about 40 miles an hour, it shifts. i can't be sure as to where its 3rd or 4th gear but either way it begins to shake badly (entire vehicle). if i put it in neutral it stops shaking immediately and if i speed up or slow down it stops shaking. also it doesn't shake when i rev it up in park. only when i'm driving and accelerating in that certain gear. what is causing this problem?

 

Inspect all the u-joints on the front and rear driveshafts, they should be tight with no play, also check the u-joints in the front axle if your truck has 4 wheel drive. Also check your wheels for being bent and any loose lug nuts.

Because you are only feeling it shake while moving, it has to be related to something that is spinning while driving.

 

thanks. i'll check it out tomorrow and let you know how that goes

 

I say check the stupid things first. Make sure none of the balancing weights fell off your tires, sometimes they put them on the inside of the wheel too.

 

Might have spun a weight off the drive shaft also. Question here, you say if you speed up or slow down it stops shaking. If I understand it only shakes at one point during a perticular speed around 40mph and during a shift. From what I understand here I would drop the tranny pan and check for metal. Could have chipped a gear. A lost wheel weight, bad u-joint, bent rim, or even a spun wieght of the drive shaft, once you reach the speed of vibration it will usually continue till you get below that speed again.

 

alright guys. i've made sure i had plenty of ATF, changed the oil today, and checked the U-Joints. they're perfectly fine. i talked to my trusty mechanic.. lol. he said that my bands probably need re-adjustment in the transmission. is that really a possible problem to cause this shaking?

 

If they are too loose then yes. The transmission will just magnify the shutter into a shake making it feel worse.

 

alright thanks. i'm heading over there today.