2015 Platinum 3.5" lift with driveline Shudder/Vibration

[W219cls55]

Hey guys, just a little tip from my experience after I did a 3.5" lift on my Platinum. 3.5" front and 5" tapered block in the rear. Well I finished the lift and took it for a drive of course well while entering highway I gave it 3/4 of the throttle from 20-70mph and at around 55mph I felt a fine vibration that I had never felt before. Mind you I've had 4 superduty's from 2004(6.0)with 12" lift and 40"tires, 2005 Harley Edition same lift and tires, 2008(6.4) 8" rize 4 link, 2010 Harley Edition 6.4 w/ 4.5 stage 2 icon. And NONE OF THE EVER EVER HAD ANY TYPE OF VIBRATION. So, This truck with only a 3.5" and driveline vibration!? I was not too happy. First thing I did was put factory tires and wheels to see if it would go away but no luck. So it wasn't the wheels and tires. I started to think maybe we bent transfercase shaft or pinion but that wasn't the issue. I ended up taking it to the ford and the mechanic recommended I put factory wheels and tires(so i did) and he ended up rebuilding the whole differential and that didn't fix it. I ended up ordering some shims for the pinion angle. 2 degree and 4 degree. The 2 degree reduced it by 50% so we stacked the 4 degree making it 6 degrees and that FINALLY CURED IT and ordered flat PMF 4.5" blocks that get here tomorrow.

In CONCLUSION:
If you have a one-piece driveshaft I recommend FLAT BLOCKS and not TAPERED. Hope this helps and sorry for the bad grammar but I am typing from my phone lol

 

[dsmracing1]

Hmm interesting. My 14 F350 Platinum must have the 5" flat blocks then since I do not have this vibration after the install of the 3.5" kit...

 

[UNBROKEN]

There's a reason driveline angles should be matched...and you just found it.

 

[under construction]

Thats strange. I have a tappered 4" block in the rear of mine, been in there for 50,000 miles with no issues. I have been considering going to a 5" tappered and traction bars because it sits a bit lower in the rear than I like. Whos rear blocks?

 

[14ccd]

Hmm, I got the same vibration with just a 4 inch block on my dually.

 

[under construction]

Hmm, I got the same vibration with just a 4 inch block on my dually.[/QUOTE

Straight or tappered?

 

[14ccd]

Straight, I just went out to verify.

 

[under construction]

I think it has a lot to do with the length of drive line among many other things. OP who manufactured the blocks and what cab and bed configuration do you have?

 

[14ccd]

After reading again the first post my vibration occurs when I first leave from a stop, or at low speeds like when turning a corner then accelerating then goes away after 20mph. I thought it might be axle wrap but maybe not.

 

[UNBROKEN]

It has everything to do with the relationship of the pinion to the tailshaft with a 1 piece driveshaft.

 

[under construction]

I agree with what you are saying but a tappered block typically helps with this issue and does not hinder it. Correct?

 

[14ccd]

My truck is a crew cab long bed so I have a two piece driveshaft but the principal still applies.

 

[W219cls55]

Hmm interesting. My 14 F350 Platinum must have the 5" flat blocks then since I do not have this vibration after the install of the 3.5" kit...

ok, What about the driveshaft, is it a one piece ot 2 piece with carrier bearing.

Thats strange. I have a tappered 4" block in the rear of mine, been in there for 50,000 miles with no issues. I have been considering going to a 5" tappered and traction bars because it sits a bit lower in the rear than I like. Whos rear blocks?

I ordered 2 sets: 1-4.5" PMF and 1-5"Icon. I'm gonna try the 4.5" first because I have the firestone ride rite and it's much more time consuming to disassemble and reassemble. So, if with the 4.5" it sits too short from rear I will do the 5".

Hmm, I got the same vibration with just a 4 inch block on my dually.

Is yours a 2 piece or a 1 piece driveshaft?

I think it has a lot to do with the length of drive line among many other things. OP who manufactured the blocks and what cab and bed configuration do you have?

The ones I have currently? Pro comp 5" blocks. The new ones PMF 4.5"and Icon 5"

After reading again the first post my vibration occurs when I first leave from a stop, or at low speeds like when turning a corner then accelerating then goes away after 20mph. I thought it might be axle wrap but maybe not.

Do you have carrier bearing?

It has everything to do with the relationship of the pinion to the tailshaft with a 1 piece driveshaft.

Yes it sure does! It took me 1 month of trial and error.

 

[W219cls55]

Oh shoot!!! I can't believe I forgot to mention that I even went and bought a new HD ALUMINUM DRIVESHAFT because the slip yoke was "supposedly" sticking out too much and It was probably the one causing the driveline vibration. Set me back $880 dollars! Heres a pic of the slip yoke sticking out about an inch more.

 

[W219cls55]

And here are pics of the new resized driveshaft.