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Discussion Starter #1
I’ve been trying to figure this out since installing my lift. 12v and nv4500 with nv271 in a ford van.

It’s gotta be driveline angles but just wondering if anyone has experienced similar vibrations. It starts around 55 when I shift into 5th. Smooths a bit when I get to 70 but still there. Not too present in 4th but I don’t really push it up to 60 then.

Vibration also seems to settle when I left off the pedal.

I installed some shims but maybe I’m still a couple degrees too low...

Everything is new. Hubs, diff, u joints, brakes.

Any thoughts?

Thanks.


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Wheel/tire balance maybe? Did it only start when you lifted it? Not sure what the driveline looks like on that. Is it a one piece or two piece shaft?

Also, you got a build thread anywhere? That 4wd van setup looks pretty awesome.
 

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My only thought is that a 12 valve manual shift, 4x4 van is cool as $hit and I want one.

One a more serious note, try getting a go-pro style camera and mounting it under the truck and taking it for a drive. Assuming your drive line angles are within the unacceptable range of the joints you're using, you might be looking at a drive shaft imbalance issue (perhaps being exaggerated by the higher angles).
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Discussion Starter #5
I don’t really have a thread anywhere bc I never sit down to go back over it all. I know I should but by the time I finish a task I’m f’ing over it and wishing I was hanging with my gf or friends haha. This is my first project this size and it’s taken me so much time to research and do everything right. (Except this vibration of course)

Wheels and tires have been rotated and balanace 3 times now.

Driveline is CV behind the t case which is a Ford 271 with dodge input shaft.

I put a 2005 Ford 10.5 in the back when I did the lift and didn’t know the level of importance of angles at the time so I just used a pipe to get it close before having the perches welded on.

After getting the shaft rebalanced I then learned the pinion angle needs to be ideally about 1.5* lower than the driveshaft angle so I measured and realized the pinion was actually too high. I had some shims made to bring it down.

I’ll go measure again tonight to confirm where it is now. I’m measuring on the pinion flange and under the driveshaft.

Assuming it’s not tranny related I’m guessing either I need to reshim or maybe driving with it not quite right got the shaft wonky and I need to rebalance it again now that I have the angle correct.

It’s just frustrating dealing with this as my valair clutch is starting to slip again due to what I assume is leaky rear main seal or trans input seal. Both things I’ve done many times before and felt confident about.

Ugh I just want this thing to be done so I can get a winch on it and go play in Utah already.

Here’s a pic of the van with my boat that has a 4bt I rebuilt too!






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Discussion Starter #6
My only thought is that a 12 valve manual shift, 4x4 van is cool as $hit and I want one.



One a more serious note, try getting a go-pro style camera and mounting it under the truck and taking it for a drive. Assuming your drive line angles are within the unacceptable range of the joints you're using, you might be looking at a drive shaft imbalance issue (perhaps being exaggerated by the higher angles).

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Should I just aim it at the driveshaft and it would be obvious?


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Should I just aim it at the driveshaft and it would be obvious?


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You'll likely have to make a couple goes at it. I'd set it up to aim the camera at the rear u-joint (where the drive shaft connects to the rear end) first as high torque motors (like 12 valve cummins) tend to cause a little axle wrap on leaf spring vehicles (especially if lifted with blocks). If that isn't the issue the re-aim the camera at the carrier bearing (if you have one), then the transfer case rear output joint and see what's going on.
Go-Pro cameras and their knockoffs are pretty cheap now. I've used one to find a front end clunk in a friends truck before, we just kept aiming the camera at the various joints (4X4 IFS Chevy truck, lots of joints in them things) until we found the one that was causing the clunk (strangely enough the bolt hole in the frame mount for the lower control arm had worn into an elliptical shape somehow causing the control arm to move around with a clunk , all the ball joints where still good on that truck).
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Discussion Starter #8
You'll likely have to make a couple goes at it. I'd set it up to aim the camera at the rear u-joint (where the drive shaft connects to the rear end) first as high torque motors (like 12 valve cummins) tend to cause a little axle wrap on leaf spring vehicles (especially if lifted with blocks). If that isn't the issue the re-aim the camera at the carrier bearing (if you have one), then the transfer case rear output joint and see what's going on.
Go-Pro cameras and their knockoffs are pretty cheap now. I've used one to find a front end clunk in a friends truck before, we just kept aiming the camera at the various joints (4X4 IFS Chevy truck, lots of joints in them things) until we found the one that was causing the clunk (strangely enough the bolt hole in the frame mount for the lower control arm had worn into an elliptical shape somehow causing the control arm to move around with a clunk , all the ball joints where still good on that truck).
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Sweet thanks for the pointers! I’ve got a go pro so I’ll try to do that in the next couple days. The lift is all springs + the 7* shims I got to bring the pinion angle down a little. But yea maybe there’s more wrap going on then I’m accounting for or maybe o even shimmed it down too far. I’m about to go for a ride and then I’ll measure angles again and report back.

Thanks again everyone.


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Discussion Starter #9
I would start off by measuring your driveline angles and go from there.


Here’s some photos of measurements I just took. The first four photos are looking in from the driver side and the last two photos are looking in from the passenger side

I’m going to measure a few more times since the flange bolts made it difficult to find a good flat face to place the angle finder.

GoPro tomorrow...

Also to clarify there is not a carrier bearing in this setup.





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Could you clarify on exactly which parts of the driveline each of these pics are? Trying to do the math, and i think I've got a good guess on each one, but I'm not all that familiar with the underside of a Ford van...

In general the angle of the shaft itself is irrelevant, what matters is the angle of the inputs and outputs and how they're related to each other.
 

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Discussion Starter #11
Could you clarify on exactly which parts of the driveline each of these pics are? Trying to do the math, and i think I've got a good guess on each one, but I'm not all that familiar with the underside of a Ford van...

In general the angle of the shaft itself is irrelevant, what matters is the angle of the inputs and outputs and how they're related to each other.

The pics are looking in from the side at the bottom end of the.

It has a double carden joint at the t case output flange. With those you’re supposed to have the pinion angle be a degree or two under the shaft angle to account for axle wrap.

TONS of great information on driveline angles from Roger here: https://www.4crawler.com/4x4/ForSale/Shims.shtml


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Discussion Starter #12
Trying to get a video uploaded to YouTube from my GoPro but having some sort of issue halfway through loading.

Anyways, it’s hard to see the shaft vibrating but it’s pretty clear I have a decent amount of axle wrap. Does that not matter a whole lot until up to highway speeds? That’s the only time I feel it


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Does that not matter a whole lot until up to highway speeds? That’s the only time I feel it
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Possibly.
Rotating equipment vibration is primary affected by three things; mass, stiffness, and running speed (there is also natural frequency and the interaction of natural frequency with running speed, but natural frequency is also changed by mass and stiffness).
Since mass isn't changing that leaves stiffness and running speed. Running speed (of the driveshaft) will obviously be higher at highway speeds.
Have you tried shifting into 4th gear and maintaining the same speed (assuming you have the engine RPM to allow for that)? If the vibration remains you may have a driveshaft imbalance or alignment issue. Imbalance is obvious, go get the driveshaft balanced.
Alignment could either be the angle of the joints or how centered the joints are to the rotating center of the shaft , usually fixed by installing new u-joints.
Since you do have a decent amount of axle wrap, adding a control device like dual traction bars or even a single anti-wrap bar would be a good idea. They may not fix the vibration issue, but it'll make the van handle better and make it less likey to break something.

Not to de-rail the thread, but how did you manage to work out the manual shifter in the van?? I had a econoline e-350 back in the day with a 460 gasser in it and with dog house removed I could adjust the carburetor while driving it down the road. Assuming you have a radiator and inter cooler in front of the engine, combined the the long inline 6bt, the transmission shift tower has to be coming through the floor under the back seat. How did you work it such that the driver can shift the transmission?
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Discussion Starter #14


Stick is rotated 180 from dodge truck orientation and then also cut and turned a little.


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Discussion Starter #15
I had the shaft rebalanced before i installed the shims. I’m going to do it again when I have time before anything more.

U joints, and entire drivetrain and suspension have under 10k on them.

4th gear has vibration present at same speed but not as pronounced as in 5th. My initial thought is that’s due to 5th at 65 being right in the peak toque rpm while in 4th it’ way over.


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