Vibration under acceleration after 80E swap
04-23-2014, 01:46 PM
#23
I would measure your driveline angles and shim where you need it. If you were factory with a single you should be fine... After all in most applications you wil need a shorter driveshaft. I most definitely needed a shorter shaft... Only reason I say most is because of what was mentioned earlier in the thread.
04-23-2014, 01:50 PM
#24
My tranny points down 6*. My pinion points down 3*. I have no vibes but i used to get them.
Something yall might want to think about is that your measuring the static/at rest angles. When you get heavy on the gas the rear end will rotate upwards. Sometimes alot. Depending in if you have rubber, poly, or solid leaf spring bushings will determine how much it will deflect. I swapped out every rubber bushings on my leaf springs and shackles to poly for less deflection. I also added some assasin bars to also limit the movement. So with all that i had no vibes at any speed or acceleration/load.
Something yall might want to think about is that your measuring the static/at rest angles. When you get heavy on the gas the rear end will rotate upwards. Sometimes alot. Depending in if you have rubber, poly, or solid leaf spring bushings will determine how much it will deflect. I swapped out every rubber bushings on my leaf springs and shackles to poly for less deflection. I also added some assasin bars to also limit the movement. So with all that i had no vibes at any speed or acceleration/load.
04-23-2014, 01:58 PM
#25
I would measure your driveline angles and shim where you need it. If you were factory with a single you should be fine... After all in most applications you wil need a shorter driveshaft. I most definitely needed a shorter shaft... Only reason I say most is because of what was mentioned earlier in the thread.
my truck will have traction bars so i shouldnt have to worry to much about axle movement
04-23-2014, 02:05 PM
#26
My tranny points down 6*. My pinion points down 3*. I have no vibes but i used to get them.
Something yall might want to think about is that your measuring the static/at rest angles. When you get heavy on the gas the rear end will rotate upwards. Sometimes alot. Depending in if you have rubber, poly, or solid leaf spring bushings will determine how much it will deflect. I swapped out every rubber bushings on my leaf springs and shackles to poly for less deflection. I also added some assasin bars to also limit the movement. So with all that i had no vibes at any speed or acceleration/load.
Something yall might want to think about is that your measuring the static/at rest angles. When you get heavy on the gas the rear end will rotate upwards. Sometimes alot. Depending in if you have rubber, poly, or solid leaf spring bushings will determine how much it will deflect. I swapped out every rubber bushings on my leaf springs and shackles to poly for less deflection. I also added some assasin bars to also limit the movement. So with all that i had no vibes at any speed or acceleration/load.
04-23-2014, 06:02 PM
#27
TECH Enthusiast
04-23-2014, 07:02 PM
#28
Vibrations appears to be half the story, the other half seems to be the operating angles for maximum u-joint life. Here's a pic of my rear end after dropping it 4" and putting the pinions shims in the wrong way. It did not vibrate at all, but as you can tell from the pic, it's not a good setup.
04-23-2014, 11:13 PM
#30
Absolutely! My point was that even with the angles as bad as this, there wasn't vibration, even under heavy load. Reducing vibrations isn't the only reason to have correct angles.
This was a pic from awhile ago immediately after the 4" drop in the rear with the pinion shims the wrong way. I only drove it like this for a few miles before I noticed and fixed it. I agree, it was awful, but surprisingly no vibrations.
This was a pic from awhile ago immediately after the 4" drop in the rear with the pinion shims the wrong way. I only drove it like this for a few miles before I noticed and fixed it. I agree, it was awful, but surprisingly no vibrations.