I been chasing this high speed vibration for some time now. I believe something isnt right after the gear install but mybay its my pinion angle. The current pinion angles are (TRANS -4.4 pointing down... DRIVE SHAFT point down into the pinion or upto the trans depends and how you want to look at it 2.5 and PINION +4.3.....) I just had a new transmission built by ACE and now i can fell the vibrations more sine everything inside the trans is nice and tight. The drive shaft is a one piece from texas drive shafts 5in aluminum high speed balance 1350 spicer ujoints....

Do my angles looks off....this is driving me carzy i am thinking something is wrong with the pinion gear install....The vibration is a high speed vib that starts around 75mph and gets worse with speed....

 

Does it vibrate if you put it in neutral? When you are in the throttle it will force the pinion up a few degrees.

 

Hmmmm....

Dont think its going to work since when i left off the throttle it continues to vibrate until i get under 75mph...but it worth a shot

Going to have to try that in the morning..will post finding after the neutral test...

 

Well getting the truck to make the vibration and put it into neutral didnt help any... No change in intensity or anything....thinking it might be backlash issues

 

it could be a bad u-joint, did you check them before reinstalling the dshaft? Also check to make sure no weights are missing.


Are the u-joints in line?

 

All the caps look good and doesn't appear to be missing any weights that were welded on..

What do you mean by line...like phased

 

if it looks like the drawing you posted, that's your problem. The pinion and drive shaft should meet and form a V not a ^ or -

 

Pinion Angle - Wolfe Race Craft

 

you subtract the driveshaft angle from the pinion face angle. You have ~ 1.8+ pinion angle according to your drawing. That's where your vibration is coming from

 

had seen that link..everyone talks about parralle lines and such...will give it a shot this weekend to see what going on....thank for the info..willl keep everone posted...