Drivetrain vibration w/ 283 and t5

[Dhaak64]

It’s a slip yoke that goes onto the transmission output shaft.

[Dhaak64]

Just got done taking a look at everything, and found out one of the ears on my driveshaft is bent! It’s causing the u joint to bind on one side while the yoke side moves freely. I took the joint apart and there’s apparent wear on the cross of the ends that were binding. This would make sense why I could hear it more than feel it, as there was no slop in the joint. Thank you so much everybody for your responses, and getting me to look at this in different ways.

I did look at my trans to diff angles from above and they appear to be inline. I ended up using a string stretched out under my truck with jack stands, and hung a plumb bob to center the string under the diff pinion, trans shaft, and harmonic balancer bolt. My dad suggested that method and it seemed to be a pretty accurate way of doing it for those that may need that info.

I measured my trans angle at 4 degrees down, and my pinion angle 1 degree up. I’m thinking after I get a new driveshaft I’ll set the pinion to 3 degrees up since I have the shims. I’ll report back once I get it back together with a new shaft. Thanks again everyone!

[mongocanfly]

glad you found it!!

[OBS454]

That's great. Calls for a celebratory drive with your dad to DQ. BTW did the manufacturer give it to you like that

[geezer#99]

Originally Posted by Dhaak64

I did look at my trans to diff angles from above and they appear to be inline. I ended up using a string stretched out under my truck with jack stands, and hung a plumb bob to center the string under the diff pinion, trans shaft, and harmonic balancer bolt. My dad suggested that method and it seemed to be a pretty accurate way of doing it for those that may need that info.

You don’t want them inline, you want them parallel.
Easier to measure where tranny sits in frame first. Measure from frame rail to yoke shaft on both sides. The distance shouldn’t be Equal. It should be less on the passenger side.

[Dhaak64]

Originally Posted by OBS454

That's great. Calls for a celebratory drive with your dad to DQ. BTW did the manufacturer give it to you like that

I was the one that bent it. I had some needles lay over in the bearing cup, and tried to press it together like that when I first got the shaft. Needless to say, I had to use a lot of force to get it back apart after that happened, and I’m positive that’s when it got bent..

[Dhaak64]

Originally Posted by geezer#99

You don’t want them inline, you want them parallel.
Easier to measure where tranny sits in frame first. Measure from frame rail to yoke shaft on both sides. The distance shouldn’t be Equal. It should be less on the passenger side.

I did also measure the distance from the transmission to the diff by placing a straight edge on the output shaft of the trans and one on the yoke of the diff. I then measured the distance on both sides of the straight edge to make sure that the angles were parallel by ensuring the distances were the same. I was off by a 1/16th, and was able to slide the trans over enough to get the distances the same.

[geezer#99]

So was your tranny centered in the frame or offset?

[Dhaak64]

Originally Posted by geezer#99

So was your tranny centered in the frame or offset?

I never measured using the frame rails due to the differences there can be in those. See attachment for how I measured those angles when viewed from the top.

[mongocanfly]

it could be offset and youd still get the same measurements with all things equal...best way is measure from center of trans to both frame rails and center of diff to both frame rails... or set up a center line and use plumb bob

[Dhaak64]

I replaced the driveshaft and the vibration is still there and has gotten worse. The transmission angle is 4 degrees down, the driveshaft angle is 2.7 angles degrees down, and the pinion angle is 0.9 degrees down. I used spicers torsional analysis calculator along with TREMECs angle finder app, and my current setup is within the limits for operating angles.

I then squared the engine and transmission in the frame measuring the harmonic balancer bolt, the center of the output shaft, and the frame rails. It’s offset to the drivers side 3/16” front and rear. The rear end is centered in the wheel wells. I have the results from a four wheel alignment I had done, and the DR wheel is toed out -0.3 degrees, and the PR wheel toed in 0.14 degrees. This tells me that my diff is a little crooked. The vibration definitely feels like it’s coming from the driveshaft, and it’s noticeably worse after these changes.

http://www.dragzine.com/tech-stories...s-engineering/

[OBS454]

Well, since the part you touched caused more of a vibration, I would take the driveshaft in to check high speed alignment and balance.

[Dhaak64]

I may have to consider that. The driveshaft was built by fastshafts, and ordered through summit.

I tried moving my pinion angle to 2.9 degrees too, and it seemed to improve the vibration in the lower speeds (45-65), but starts to come on strong after 70.

[mongocanfly]

pinion angle should be up...not down... pinion centerline and engine/trans centerline should be parallel to each other...

[Dhaak64]

The pinion is pointing upwards. The slope is down from front to back as required for the driveline analysis. I should’ve clarified that. I understand that the pinion centerline needs to be parallel with the pinion centerline, and that’s why I squared my drivetrain within the frame as the rearend should be pretty close to perpendicular with the frame. I understand that the pinion of a 12 bolt is offset by a half inch, and this causes an angle in the driveshaft thus requiring parallel angles beteeen drivetrain and differential.

[Captainfab]

If your engine and trans are at 4* down, your pinion needs to be up at 4* at ride height.

[Dhaak64]

So I’ve had my pinion at 0.9, 2.9, and 4 degrees up. None of these settings have changed the noise and vibration at all. I got my wheels/tires balanced just to isolate what I’m hearing, they had thrown a couple weights so they needed it.

I’m starting to wonder if there’s something going on with my differential. The noise seems to be coming from back there, especially the vibration as I can feel it in my seat, and it’s strong enough to rattle the change in the ash tray when approaching 80. The noise around 70, sounds a lot like a washing machine in wash mode going chicka-chicka-chicka. There’s also a lower pitched rumble that goes in the same pattern. Around 80 is when it becomes a solid rumble and the vibration can be felt more so.

On the rear end. A buddy and I re-geared it from 3.08 to 3.73’s shortly after the transmission conversion. It’s hard to remember exactly, but the noise might have started after that. The ring and pinion were used parts along with the carrier. We installed a new complete bearing set with axle bearings. He set the backlash, pattern, crushed the crush sleeve, and set the bearing preload. One thing I noticed after all this, is that the pinion seal started leaking pretty quickly. However, there is no up or down, or side to side movement in the pinion and the backlash seems good still.

I’m thinking to just have a gear and driveline shop take it over at this point since I don’t have the specialty tools or experience to mess with the gears, and I want it gone for good.

[Dhaak64]

I was considering taking the cover off to inspect, but it might be better to leave it alone so that the shop can see the oil that's been in there to help them find out what's going on with it. Is this reasonable?