Drive line angle advice

Some great ideas here thanks! I was thinking of just leaving it alone. I mean its only when slowing down, and it even goes away after warming up.

 

I think meant to read the slip joint is not extending. But another good thought.

 

Correct. Thank you.

 

Well what if I put a 2 or 3? degree axle shim in skinny side forward? This would put the rear pinion down around 1 degree. This would also put my rear shaft around 4.1 degrees. Wouldnt this work?

 

Some threads for ya if you want to do some light reading lol.

https://www.tacomaworld.com/threads/drive-shaft-vibrations-solved-step-by-step.244535/

https://www.tacomaworld.com/threads/just-fixed-driveline-vibration-for-free.153050/

https://www.tacomaworld.com/threads/driveshaft-angles.465292/



Good luck. I myself went from 3 degree shim and CB drop, to no CB drop, to no shim, to CB drop, to adjusted CB drop. At all times my numbers were "right", but my truck wasn't. It's probably still not perfect, but I have no real vibes anymore. I don't even know what my numbers are now.

 

I also gotta ask if you did the ECGS bushing and have tried the truck in 4wd to see if the vibe goes away.
Maybe it's not the driveline that is vibrating.

 

Yeah did the ECGS with the lift

 

You took your angle measuerments with all 4 wheels on the ground I hope ?

I made up a check list to help narrow vibrations down .

https://www.tacomaworld.com/threads/vibration-diagnostics-for-all-tacomas-write-up.520607/

 

Well the Transfer case and rear pinion should be at the same angle or down right? So by the pic I attached if I lowered the rear with a 2 degree axle shim fat side forward. This would give me a down 1 degree angle on the rear pinion. This would in turn bring inline the rear shaft at 4.1 degrees. What do yall think?

 

No correction that makes no sense. If I lowered the rear pinion that would make my rear shaft 8.1 degrees which would be way out of line with the first shaft. I can not go up on the rear pinion because that would really make the axle wrap worse. Oh well guess I will just live with it.

 

There's slope and working angles...do you know the difference? I ask because, you only ever mention slope.

If you want to do it that way and ignore the first 3.8 working angle, then the pinion needs the same slope as the first shaft.
So a 5 degree shim, skinny side forward.

 

So I guess my real question is what measurements will tell me what axle shim I will need? I dont want to guess.

 

Slope is what you measured; working angles are the difference between adjacent slopes.

You need:
A+B+C=0

You have:
3.8+2.3+(-7.1)=-1

If you had:
3.8+2.3+(-6.1)=0
You can get this with a 1 degree shim; skinny side forward.

Axle wrap under braking lowers the pinion; under acceleration it rises. This increases the C working angle under braking. Conversely, it decreases under acceleration.

Let's back up a second though...
It was there before and after the lift.
It's there regardless of brake use.
You sure it's not the fuel cut-off the manual guys bitch about?

 

Yeah im sure its the drive line according to the dealer and I can hear it coming from the first part of the shaft. Would it be wise to go with a 2 degree shim to compensate for axle wrap as well. It was there before and after the lift.

 

Probably not a bad idea.
I was going to suggest a 2 degree, but didn't want to muddy the waters.
Sounds like you got it now.

 

If it was there before the lift, maybe the shaft is out of balance.
I would not discount other causes.

 

One more question.... Since the rear pinion is 1 degree up compared to the transfer case I will need to have the shim fat side forward?

 

You're still thinking equalizing slopes...think equalizing working angles.

Fat side rearward; this rotates the pinion upward, lessening the C working angle.

 

So I did the measurements again this time on level ground. I wanted to find the correct axle shim size. Front pinion angle 5.59 rear pinion angle 5.94 +\- .3 front pinion zerod to rear pinion 0 degrees to .3.
Looking at this my pinions are very close. 1)Tcase to Trans versus rear pinion angle .34 2)T case to Trans operating angle 6.81 3)CB operating angle Front drive shaft 6.81, Rear drive shaft 10.15 difference 3.14 4)Pinion operating angle 11.21 5)Direction pointing pointing up

What next?

 

Can you give the slopes in diagram form like you did in your original post? I can't make heads or tales of your numbers.