Vibrating feeling when shifting into 4 and 5th?

[93STVCobra]

So I notice latly that when I am in 4th gear and go into 5th it seems to stumble or vibrate whatever it is. It almost feel like I am shifting at to low RPM but this isn't the case also I notice it in 2nd to 3rd sometime it rumbles crazyly.... It feel just like it almost stalling out on me.. Anyone have ideas? They're 115k miles on the tranny

 

[Noobz347]

Is the vibration RPM or speed dependant, or are you able to tell?

 

[93STVCobra]

Speed, 100% sure it isn't RPMs


Edit: I'm not reving it from N to like 2k + into 5th and having it stumble on me either

 

[Noobz347]

I would crawl up underneath that car and shake, rattle, pull, push, and pry, on both drive-shaft u-joints to see if there's any slop whatsoever. If not, I would STILL replace both U-Joints before I attempted to troubleshoot any further.

They're what... $8 to $16 a piece plus installation (if you don't put em in yourself).

 

[michaelg10]

Use precision u-joints, same thing happened to me. No more vibration over 35. Well that and a different axle.