Driveshaft Angle

[ryan.sampson]

Ok so I've been doing a lot of research here about this, but here's whats happening:

I had a Procomp 4" lift, I added a bigger TAPERED block to the rear, and the mini pack to the front

I bought the tapered block for my carrier bearing, and added a small shim also, which worked great its all in line. My pinion angle is 8*, my rear rear drive shaft is at 10* and my upper rear driveshaft is at 9.5*, and my tcase angle is 4*.

Before adding the lift, I never realized that the vibe when i took off could be from the carrier bearing, as the truck came with the lift. So i have all of my angles in tack, and have had my tires balances twice, and I still got a decent vibration at takeoff, and almost like a skip feeling bad around 40, and again around 60. its driving me nuts i can't figure it out! any guidance? my carrier bearing is worn, its got some play, the vibration is 100X worse than a week ago. any ideas??

[Chad29860]

Drive shaft angles are a hard thing to mess with. I have been messing with lifted vehicles since I was young and the one thing an old timer taught me was that all angles had to eqaul in order to cancel out vibes. if you where to draw a line from your transfer case output shaft straight out and your rearend pinion straight out the two lines should be parralel. With two pieceshaft this all gets more difficult. I would start by removing the shim on the carrier bearing and replace the carrier bearing. Just run the angle block on the carrier bearing. If I am not mistaking the driveshaft from thransfer to carrier bearing should follow relatively straight out the back of the transfer and then angle down to the rearend after the carrier.

[smokeum99ta]

Which way is your pinion angle facing? If the pinion is pointing upwards its only gonna get worst. You want the pinion angle lower than the driveshaft so that when you accelerate the opinion moves up, therefore straightening out the pinion and driveshaft. The other way is just creating more bind in the u-joint and will wear it out fast.

[ryan.sampson]

My pinion is angled up from level, i drew up a quick drawing in paint to show you what i meant. i've read online that you want a difference of a 1/2 degree between the driveshafts, and a 2 degree difference between the shafts and the pinion, am i wrong here? i'm hearing every which way..

if i were to straighten everything in line with itself, i'd have to angle the axle 2 more degrees up

[ryan.sampson]

Originally Posted by Chad29860

Drive shaft angles are a hard thing to mess with. I have been messing with lifted vehicles since I was young and the one thing an old timer taught me was that all angles had to eqaul in order to cancel out vibes. if you where to draw a line from your transfer case output shaft straight out and your rearend pinion straight out the two lines should be parralel. With two pieceshaft this all gets more difficult. I would start by removing the shim on the carrier bearing and replace the carrier bearing. Just run the angle block on the carrier bearing. If I am not mistaking the driveshaft from thransfer to carrier bearing should follow relatively straight out the back of the transfer and then angle down to the rearend after the carrier.

Before i added the shim, it was horrible at takeoff, far worse than now, but i do agree i need to replace the carrier bearing to fix the shimmy, my thought process is to get it all right, and then fix it, so i dont destroy the new one

[smokeum99ta]

Originally Posted by ryan.sampson

My pinion is angled up from level, i drew up a quick drawing in paint to show you what i meant. i've read online that you want a difference of a 1/2 degree between the driveshafts, and a 2 degree difference between the shafts and the pinion, am i wrong here? i'm hearing every which way..

if i were to straighten everything in line with itself, i'd have to angle the axle 2 more degrees up

From your drawing the pinion angle is pointed the right way. If I was you I'd replace all the u-joints and carrier bearing then see if the problem continues. Then if the vibrations continues start adding/subtracting shims from the carrier bearing to see if it gets better or worse.

[Chad29860]

I would definately replace carrier and check joints. You would be surprised how much vibes a bad carrier will create. With a standard style shaft you want the angels to be equal at the transfer and rearend. The only time you want the pinion facing the transfer case out put is when you are running a constant velocity shaft. The eqaul angles on top and bottom help cancel vibes.

[ryan.sampson]

I agree with replacing the carrier bearing, but the ujoints all have less than 5k on them, and the carrier was hardly noticable before.. which makes me think that something else is still off.... is it easy to "clock" the transfer case? is that something i should be thinking about?

chad, are you saying then there's too much tilt in the axle when compared to the tcase? should i lower the tcase? whats a good difference to shoot for?

[Chad29860]

Originally Posted by ryan.sampson

I agree with replacing the carrier bearing, but the ujoints all have less than 5k on them, and the carrier was hardly noticable before.. which makes me think that something else is still off.... is it easy to "clock" the transfer case? is that something i should be thinking about?

chad, are you saying then there's too much tilt in the axle when compared to the tcase? should i lower the tcase? whats a good difference to shoot for?

Have never heard of having to do a transfer case drop on a f250 but may possibly help. Also what joints are you running because I have had problems with cheaper parts store joints. I run nothing but Spicer factory replacement joints. The problem with vibrations is there are so many variables. Do you notice a vibration when just accelerating or is it there when there is always a load? When you let off it and coast does it go away?

[ryan.sampson]

Originally Posted by Chad29860

Have never heard of having to do a transfer case drop on a f250 but may possibly help. Also what joints are you running because I have had problems with cheaper parts store joints. I run nothing but Spicer factory replacement joints. The problem with vibrations is there are so many variables. Do you notice a vibration when just accelerating or is it there when there is always a load? When you let off it and coast does it go away?

its pretty bad under acceleration under 20, and when cruising at 40 or 60ish its there less under load but when cruising at a steady speed it doesnt go away until i mash on it or slow down significantly

and they're the cheap napa ones