[Wicked Mayhem]

im getting some vibration around 70 on the freeway. finally got off my ass and decided to check..

off rear end i got -3°
under the tailshaft on the tranny, i got -2.5°
then on the pan i got 0°

now i am not sure i am measuring off the right spot on the tranny.

i have read its good to have -1° to -2° of what tranny is sitting still, so when your accelerating/in motion it is spot on with tranny output angle.

at rear end.. -3°

on pan.. even though im sure it means nothing as to pinion angle.. 0°

red line is where i checked pinion angle.. -2.5°

help?

 

[Wicked Mayhem]

so if i am measuring off the right points, i can add my 4° shims to make my rear end +1°. so when driving it is +2° ish which will nearly be exact opposite of my tranny angle.


now.. -3° on left and -2.5° on right

after 4° shim.. +1° on left and -2.5° on right

 

[chevytruckguy]

Take a large socket the same diameter as the u-joint cap, then measure off of the flat end. the yoke cap should give you the same angle as the trans. The yoke will have to be pointing straight down to get an accurate measurement. Make sure you measure the cap that is attatched to the trans yoke, there is one for the driveshaft. I measured all the angle on my truck this way. Also what is the driveline angle.?

 

[Wicked Mayhem]

hopefully my measurements are right. i started putting shims on. got one side done. came in side to see if any replies to this..

 

[Wicked Mayhem]

no vibration, but now drive shaft rubs!! wee!!

 

[nick993]

no vibration, but now drive shaft rubs!! wee!!

if i remember correctly, crewcabs rub driveshaft when its that low. maybe try a 2 degree shim. it might stop vibrating but clear the shaft.

 

[GMracer]

yea you want the rearend pointing up 3 and the trans down three looks like you got the right idea. But on CC you may want to think about running a 2pce.

 

[Wicked Mayhem]

if i remember correctly, crewcabs rub driveshaft when its that low. maybe try a 2 degree shim. it might stop vibrating but clear the shaft.

yeah its rubbing on both gas tank crossmembers. i dont have any other shims, and its getting no vibrations now so ill keep that as is.

yea you want the rearend pointing up 3 and the trans down three looks like you got the right idea. But on CC you may want to think about running a 2pce.

i am going to pull the bed off tomorrow and notch the crossmembers. i have the whole week off and dont want to spend money. the rear crossmember will be easy to notch, but the front one might be a little bit of a pita since its under the cab.

actually.. i might just drop tank, and raise the crossmembers. it hasnt drug yet, but better safe than sorry right?

how much exactly do i need to raise both crossmembers?

 

[ILuvJDM]

yea you want the rearend pointing up 3 and the trans down three looks like you got the right idea. But on CC you may want to think about running a 2pce.

are those good numbers for my truck as well?

 

[GMracer]

thats basically industry standard. whatever you tranny points down at you want your rearend to point up at the same angle. Doesn't matter what drop or lift, at your ride height that is the number it should be.

 

[ILuvJDM]

awesome, thanks. So the points that the OP measured at are where you should measure? I was trying to figure out where to measure from when I was under the truck

 

[Trey]

I am in the process of bagging my crew cab and had to go with a 2 piece, The steel 2 piece out of a extended cab is the same length and smaller diameter, just fyi.

 

[Jaksonplayer]

You aren't going to be able to raise the front gas tank x member much, it's right under the cab. I raised the rear x member by cutting it out, welding plates to cover the holes, and welding the x member back in higher. That helped a lot, but the front x member still rubs. When I bag the rear I am going to swap in the steel two piece. Its a way better fix than trying to make room for the HUGE one piece. Those are going for about $150 around here.

I was able to raise it about 1 1/2-2in. to get it sitting flush with the top of the frame. The one piece doesn't rub on that x member anymore.

 

[Wicked Mayhem]

i notched the crossmembers.. need to take it for a drive. i know the tube crossmember wont rub, hopefully the one under cab one. i almost didnt even weld anything back in. i kinda hopped up and down on the gas tank(full tank) and the tank didnt flex at all..

this is what i welded in..(left one)