Driveshaft vibes n fixes, and a thanks to DIY4x

[Kocher93]

So some may know that I recently redid my rear suspension and swapped out blocks for some home made shackle flips. Well they lifted the truck to high and pushed the axle forward and my driveshaft has been vibrating everywhere. So I played with some shims for a weekend, but no it's vibrating like mad.
I ordered some DIY4X shackle flips and some EZ inches. All I can say is WOW I ordered these the night of thanksgiving and got them so quickly it was insane. I was expecting 2-3 weeks for all the orders to go through, holiday weekend all the more orders for the discount. Nope, got them quick so thank you Kurt and the DIY4X team you guys are on it.
On to the real question. I have a stock drive shaft 89 K5 so its a 10 bolt to a 241. So my plan is lowering the rear of the truck down to the 4 inches it should be, instead of 5.5. Then using the EZ inch offset and pushing the rear axle back 1.5 inches to lessen the angle on my driveshaft and vibrations. Does anyone have some input on my plan? I really don't want to get a new driveshaft until I swap 1 tons and my SYE. It's my DD/WW. With my blocks in the rear it sat at about 3 inches and had no vibrations at all. Sorry if my typing/grammar is terrible my GS3 touch screen is something im not good at.

 

[Mel664]

There are many type of company are famous in all over the world and there are many type of drive shaft like heavy duty,industrial,and automotive also and i don't know what type of drive shaft is suitable for you.

 

[Teck]

You may need to look into lower the transfer case cross member to reduce your angles.

 

[black dawg]

How much did the pinion angle change with the shackle flip. Are you sure the vibe isnt related to the pinion angle change and not driveshaft angle?

 

[Teck]

How much did the pinion angle change with the shackle flip. Are you sure the vibe isnt related to the pinion angle change and not driveshaft angle?

When the pinion angle change from the shackle flip and moved forward that effect the drive shaft angle, so now the angles are out of phase that is where the vibration is from. He will have to get the two angle back similar to get raid of the vibration.

 

[Kocher93]

I was playing with the shims all weekend and had so many different angles going im almost sure its the tcas angle with a 3 inch lift it rode fine now with the 5.5 lift it vibrates like crazy to where i feel somethings gonna break so my idea is having it at 4 inches like the front with a shackle flip and ez inch. So the basic question is if i move me axle back the 1.5 offset it should help the tcase angle along with the lowering it 1.5.

 

[plyr2k]

I was playing with the shims all weekend and had so many different angles going im almost sure its the tcas angle with a 3 inch lift it rode fine now with the 5.5 lift it vibrates like crazy to where i feel somethings gonna break so my idea is having it at 4 inches like the front with a shackle flip and ez inch. So the basic question is if i move me axle back the 1.5 offset it should help the tcase angle along with the lowering it 1.5.

First DO NOT drop your T-case down. This makes the front angles worse, and puts your distributor close to the firewall.

Moving the zero rate to push your axle back will not lower the truck. I would use the less offset hole in your situation.

As for the vibes, put the thick side of the shim forward. You want to lower your pinion to make more of an angle. The angles themselves don't really matter, it's both Of them together. With a single u-joint on each end you want the angles at the case and axle to be as close as possible. When you
Installed your shackle flip it lowered the rear of the axle, twisting the pinion up. I bet your rear yoke is pointed straight at the case, correct?

What length shackles did you order from
Kert? Maybe you can get some shorter shackles to lower it a little bit and help correct the pinion angle.

Instead of lowering the back, could you put a zero rate upfront?

 

[Kocher93]

Yea right now its a home made shackle flip. But even when the angles were almost even it was still shaking so im lowering it back down. My idea behind the ez inch toward the rear is so the wheel base is a little longer and lessen the angle on the tcase a little

 

[plyr2k]

Yea right now its a home made shackle flip. But even when the angles were almost even it was still shaking so im lowering it back down. My idea behind the ez inch toward the rear is so the wheel base is a little longer and lessen the angle on the tcase a little

Moving it back won't lessen the angles, as the distance u-joint to u-joint will remain the same.

 

[plyr2k]

Yea right now its a home made shackle flip. But even when the angles were almost even it was still shaking so im lowering it back down. My idea behind the ez inch toward the rear is so the wheel base is a little longer and lessen the angle on the tcase a little

Moving it back won't lessen the angles, as the distance u-joint to u-joint will remain the same.

 

[cybrfire]

If you have a double cardan joint at the top of the shaft up by the tcase, which you should being in a blazer, The lower joint at the pinion should point at the tcase but down 2*. (we'll come back to this 2 degrees later.)

That type of shaft you do not want the angles equal.

If you have the other type of shaft with a single joint on each end, then yes both angles should be the same.... and a couple degrees down on the lower joint.

All ujoints that operate at an angle vibrate. Every one of them!

If it is a single joint at each end, the two angles being the same, the vibrations from one cancels the vibes from the other.

on a double cardan shaft, the two joints together will split the angle between themselves thereby canceling there own vibrations. The single joint at the pinion being relatively straight will not vibrate enough to cause an issue and ideally you won't notice it.

Going back to that 2 degrees, the purpose of that 2 degrees... When you have a ujoint with Zero angle on it, there is no oscillation. The needle bearings become static and a couple of those needles will wear faster than the others. This will cause premature ujoint failure. There is one other reason for the couple degrees down on each shaft, when you are applying throttle, the axle will always wrap to a small degree. ( A couple degrees) Now your angles match perfect when torque is being applied.

 

[cybrfire]

I ordered some DIY4X shackle flips and some EZ inches. All I can say is WOW I ordered these the night of thanksgiving and got them so quickly it was insane. I was expecting 2-3 weeks for all the orders to go through, holiday weekend all the more orders for the discount. Nope, got them quick so thank you Kurt and the DIY4X team you guys are on it.

Thanks for the compliments, we were able to build up some inventory prior to the sale and it made a pretty big difference on response time. I wish I could say it always works out that way.

We continue to try and get things out as quickly as possible. Its an integral part of customer service and that is very important to us.

Thanks for the biz! Give me a call if you like, I'll try and help ya trouble shoot the vibes.

 

[Kocher93]

Kurt no homo, but I love you. I took out my homemade shackle flips today and swapped in yours. I didn't do the ez inch, I didn't have time today. But I got on the road and oh man that was good, no vibrations (with no shims) no axle wrap and it is a smooth ass ride. It's sagging so tomorrow or some other time the ez inch will go in, but right now I'm happy. Thank you.

 

[Teck]

Did the new shackle flip kit put you axle back in place or does it still need to be moved back.

 

[cybrfire]

Kurt no homo, but I love you. I took out my homemade shackle flips today and swapped in yours. I didn't do the ez inch, I didn't have time today. But I got on the road and oh man that was good, no vibrations (with no shims) no axle wrap and it is a smooth ass ride. It's sagging so tomorrow or some other time the ez inch will go in, but right now I'm happy. Thank you.

Good to hear and Thank you!

 

[Kocher93]

Im not to sure on the axle location but it looks stock location. My only problem now is underload theres a loud clanking or clattee coming from somewhere in the drive train i only hear it under first seconds of acceleration and coast. I know my home made shackle flip was a menace to my tcase and rear end. Guess ill do u joints and top off some fluids and go from there.