Slight vibration after 2.5” lift

[Last Flight Out]

I’ve been doing a lot of research on the typical vibration after one installs a lift (I have OME 2.5” lift with Bilstein shocks, both DS balanced recently, and new u joints on rear one, transfer case rebuilt). I’m now starting to look at pinion angles and just need some guidance on the best way to do this.

Obviously with the transfer case it’s really hard to get a good angle measurement, but does anybody have any recommendations on the best way to see if I’m slightly out of parallel on the rear. I’m assuming most of my vibrations is coming from the rear, but not sure yet. Vibration happened once kit was installed.

 

[pb4ugo]

Remove the driveshaft and put the angle finder on each flange.

 

[Last Flight Out]

Remove the driveshaft and put the angle finder on each flange.

Makes sense…early morning for me

 

[charliemeyer007]

Put about 500 - 750# in the back and go for a drive.

 

[Mark Jennings]

What I found, 2.5 inch lift, 2 degree shims front and rear with ‘stock’ shackles. Add another 2 degrees in the back if run 1 inch longer shackles to level her out. The shims in the front restore the caster, the shims in the rear restore the pinion angle.

 

[GA Architect]

FWIW

I run the lower setup with a double cardan driveshaft.

 

[Last Flight Out]

What I found, 2.5 inch lift, 2 degree shims front and rear with ‘stock’ shackles. Add another 2 degrees in the back if run 1 inch longer shackles to level her out. The shims in the front restore the caster, the shims in the rear restore the pinion angle.

Thanks @Mark Jennings you are a wealth of knowledge! You provided Some good help in the archives as well.

 

[Last Flight Out]

FWIW

View attachment 3612382

I run the lower setup with a double cardan driveshaft.

@GA Architect - Yup, took the rear DS off yesterday afternoon, and the noise went completely away, and it makes sense because as I eyeballed the angle of the pinion, it was not parallel to the transfer case.

Now with that resolved, I’m about to order a Tom Woods DC rear DS. Just gotta measure the bolt holes as I’m getting more of a rectangular pattern vs perfect square.

 

[Last Flight Out]

…. After placing an order online for the DC driveshaft, I was talking to a buddy and he had mentioned to me that the double cardan may bind if I didn’t have at least 15° slope with that range maxing out at 22°. Someone at Tom’s told him this, so he opted for a single.

Now that my stress level has gone up a few, can anyone confirm this? I was doing a lot of research here and see a few people with a 2.5” lift and using DC driveshaft. I also searched their website and no where on there does it mention minimal slope angles - and a quick general Google search didn’t return anything favorable either.

I left a voicemail at Toms, but they were closed.

@Mark Jennings or @GA Architect - any thoughts here?

 

[Mark Jennings]

With the double cardan, you may still end up with shims between the axel and springs, only instead of dropping the pinion down, you may need to point it up, towards the transfer case.

The only experience I’ve had with a double cardan were on my old Chevy Blazers…..I just remember they were a bear to grease.

On my FJ40, I have a bone-o-drive, so the drive shaft is uber short, not enough room for a double. However, you should have the room and it should work.

 

[GA Architect]

…. After placing an order online for the DC driveshaft, I was talking to a buddy and he had mentioned to me that the double cardan may bind if I didn’t have at least 15° slope with that range maxing out at 22°. Someone at Tom’s told him this, so he opted for a single.

Now that my stress level has gone up a few, can anyone confirm this? I was doing a lot of research here and see a few people with a 2.5” lift and using DC driveshaft. I also searched their website and no where on there does it mention minimal slope angles - and a quick general Google search didn’t return anything favorable either.

I left a voicemail at Toms, but they were closed.

@Mark Jennings or @GA Architect - any thoughts here?

Been running a DC driveshaft on my OME 2" lift since 12/2016..... < click here >

 

[pb4ugo]

To setup a double cardin you should rotate the pinion up so it's pointing at the transfer cases output. I think Tom Woods' website has a tutorials on single and double cardin joints.

I'm getting ready to order a shims to adjust for frt caster, and this reminds me i need check the rear angles too.

 

[Last Flight Out]

To setup a double cardin you should rotate the pinion up so it's pointing at the transfer cases output. I think Tom Woods' website has a tutorials on single and double cardin joints.

I'm getting ready to order a shims to adjust for frt caster, and this reminds me i need check the rear angles too.

By eyesite, the pinion is pointing up a bit. Pic below but may be hard to tell. This is post 2.5” lift install. It was hard to find a flat surface with my cheap angle finder but was seeing about 2-4 degree angle at the pinion (again, if I am even doing this right). No shims used to date (except for the front u-bolt plates that have the built in risers).

 

[Last Flight Out]

Been running a DC driveshaft on my OME 2" lift since 12/2016..... < click here >

Yep Rick, saw that and was reading more on what you did there. Always an amazing build

 

[GA Architect]

Yep Rick, saw that and was reading more on what you did there. Was yours a 2.5 or 4” lift?

It is a 2.5" lift. I was just in my shop looking to see if I was running caster shims.....and I do not have any up front. I'm not 100% sure exactly what shims I'm running in the rear. Maybe they are 6 degrees to point my rear pinion at the rear drive plate, thus the DC driveshaft.

....Now, when I first installed the lift, I installed Cruiser Outfitter's 2 degrees shims in the rear for better geometry to use the OE driveshaft. < click here >....But I keep having a slight vibration, so I went the DC direction.

 

[pb4ugo]

Driveline Geometry 101

Driveshaft Angle Explained This video will demonstrate the proper angles for a drive shaft in a stock Jeep or Truck and how the rules change when you add a suspension lift. The video below demonstrates what is happening to the shaft at different angles, how improper angles can cause speed...

4xshaft.com

 

[mrldcty]

6 degree shims front and rear, plus a balanced DS with new bearings solved my post lift vibrations. I was ready to pull the trigger on a DC if that hadn't worked.

 

[pb4ugo]

6 degree shims front and rear, plus a balanced DS with new bearings solved my post lift vibrations. I was ready to pull the trigger on a DC if that hadn't worked.

For a 2 1/2" lift?

 

[pb4ugo]

I just went and measured my rear angles. I used the brake drum and unbolted the d/s from the pinion on the other end. It looks like I'm about 2-2 1/2" from parallel.

 

[Last Flight Out]

Well, the DC is in place and I’ve just temporarily installed it and didn’t really dress the new hardware with any Loctite at this point. Because of the new driveshaft, I am no longer able to get any kind of torque wrench on those bolts, but I’ll do the standard Loctite with as tight as I can get them for now.

After initial test drive up to 35 mph, I do not have any more vibration, but I need to get it a bit higher in speed. I’m still not convinced my rear differential is pointing as much as I want it to to the transfer case and worried that some vibration will continue to come through, but I’ll see what happens this weekend.

Just hate to add shims in the rear because it is a PITA. Borderline vomit every time I think about undoing all the ubolts, springs etc…