: case of the shakes


SP!N4L T4P
12-25-2007, 06:25 PM
after we intsalled my lift, i started getting a vibration that would hit around 20 mph, then die at 25 mph. it starts at the front, then as it dies it kinda moves towards the rear. i took it to all american 4x4 down on santa fe and they told me that my rear drive shaft needed adjusting. thats all fine and dandy, except that the vibe is comin from the front, not the rear, so im guessin, and so does Scott over at Add Off, that its the front drive shaft. i pulled out the protective plate right under where the shaft hooks up to the tcase, and sure enough there was evidence of rub-age and shear-age. but the vibe is still there. any ideas anyone?

RedRunnertc
12-26-2007, 07:56 AM
Have you tried pulling the front DS and driving without it and see if the vibration is still there?

Did you get an alignment after doing the lift? Caster could be off, and you're getting the IFS kind of death wobble.

00regcab
12-26-2007, 11:35 AM
It could very well be the rear driveshaft.

I've had similar things happen to me in my car. Granted, its a car, not a 4wd truck. But the inner CV joint on the driver axle went out, but it felt like the passenger CV was bad. So i dicked with it for hours, swapped out probably 8 different axles and then it dawned on me... check the other side. And sure enough.

It could be sending vibrations through your t-case/trans/motor then the motor mounts before you feel it

SP!N4L T4P
12-26-2007, 10:26 PM
well, due to the weather and to the fact that i have no garage to work in, i havent gotten a chance to even attempt to take out the front d-shaft, but im goin to Scott's shop to get the front geared to 4.88 and ill take it out then and try it out. also, i got two alignments done after the lift. i tell ya, a SAS keeps sounding better and better...

AxleIke
12-27-2007, 12:40 AM
i tell ya, a SAS keeps sounding better and better...

Yup. Then you can get REAL deathwobble!!!

Check to see if you've got play in your ball joints, TRE's, and/or idler arm.

SP!N4L T4P
12-27-2007, 12:59 AM
what causes SAS death wobbles anyway. my friend's K5 had one that made me shit my pants the first time it hit.

AxleIke
12-27-2007, 08:45 AM
what causes SAS death wobbles anyway. my friend's K5 had one that made me shit my pants the first time it hit.

Caster missalignment in combination with manual steering. Go full hydro and you'll never have an issue, i guarantee it.

RedRunnertc
12-27-2007, 10:28 AM
what causes SAS death wobbles anyway. my friend's K5 had one that made me shit my pants the first time it hit.

It's a resonance phenonemon, and can be brought on by a combination of several little things - caster is the biggie, but tire pressure, shock damping, wheelbase, driveshaft balance, pinion angle, worn parts, loose parts, and others all contribute.

Isaac - I think hydro is like steering stabilizers - the DW is still there, you just don't feel it as much. More of a bandaid than a true root cause solution.

AxleIke
12-27-2007, 01:33 PM
It's a resonance phenonemon, and can be brought on by a combination of several little things - caster is the biggie, but tire pressure, shock damping, wheelbase, driveshaft balance, pinion angle, worn parts, loose parts, and others all contribute.

Isaac - I think hydro is like steering stabilizers - the DW is still there, you just don't feel it as much. More of a bandaid than a true root cause solution.

Nah. You can't get the resonance on a full hydro set up. It is too large a damper. Your wheels aren't connected except through a fluid. A Hydro assist is a bandaid, but full hydro is a full blown medicine man. You can get individual wheel wobble with worn parts, but you don't feel it, since there is zero mechanical connection to the steering wheel.

Essentially, unless your wheel is about to fall off, the Hydro will damp out almost EVERYTHING. And even if your wheel is falling off, you won't feel it in the steering wheel.

On the other hand, Hydro is definitely NOT street legal. So, yeah, not really an option for a road truck.

SP!N4L T4P
12-27-2007, 07:46 PM
well, i got another problem...i finally got my 4.88's in the front and rear, and lo and behold the vibe is gone in 4x4 but still present in 2wd. however, there is another demon i gotta excerise out: when im in 4x4 (with my new 4.88's) whenever i pass 45, as soon as i let off the gas i hear a scraping/scratching sound coming from right under me, and its not clear whether its behind or infront of me. the faster i go, the louder the sound, and if im goin fast enough (70+ which isnt good in 4x4 anyway) it gets damn loud and becomes a vibe, and it only happens in 4x4, not in 2wd. did any of you have a problem like this after gearing your axles? is it just that my t-case cant handle all the new amount of pressure from both axles with 4.88?

AxleIke
12-27-2007, 11:55 PM
You're t case should be fine with the 4.88's.

Do you have any belly armor?

This sounds like a drive shaft issue, although quite strange to have it in 2 and not 4.

Here is what I would do:

Call or email Troy and Molly. See if they have a few hours on Sat.

Go over when they do have time, and remove front drive shaft. Drive it around. If you have manual hubs, unlock them. If no noise, lock hubs, no drive shaft. If no noise, stop, put transfer case in 4wd, and so forth. This should enable you to do figure it out by process of elimination.

If not the drive shaft, then I suspect transfer case, but certainly not as a result of the 4.88's.

Good luck man!

RedRunnertc
12-28-2007, 08:32 AM
w however, there is another demon i gotta excerise out: when im in 4x4 (with my new 4.88's) whenever i pass 45, as soon as i let off the gas i hear a scraping/scratching sound coming from right under me, and its not clear whether its behind or infront of me. the faster i go, the louder the sound, and if im goin fast enough (70+ which isnt good in 4x4 anyway) it gets damn loud and becomes a vibe, and it only happens in 4x4, not in 2wd.

Sounds like dry spindle bushings.

TowerRigger
12-28-2007, 09:53 AM
Sounds like dry spindle bushings.

Give it some liquor. A dry Spindle always likes liquor.:D :D

RedRunnertc
12-28-2007, 10:13 AM
Spindle likes liquor even when he's wet ...

spindleshanks
12-28-2007, 01:07 PM
Hey, it's not spindle's fault he likes to drink...his girlfriend's mom gave him a huge bottle of Jack Daniels as a Christmas present!

RedRunnertc
12-28-2007, 03:13 PM
Hey, it's not spindle's fault he likes to drink...his wife's mom gave him a huge bottle of Jack Daniels as a Christmas present!

Fixed it for ya ... if her parents are that cool, you need to marry the girl!

TowerRigger
12-28-2007, 03:43 PM
Woah now Troy. Let's not let the alcohol have us make hasty decisions.lol

RedRunnertc
12-28-2007, 04:21 PM
You met Annaliese in Steamboat ... but you probably don't remember :rofl:

Wildturkee
12-28-2007, 08:23 PM
Dont go to All American 4X4...unless you like to get RIPPED off...MMM KAY? ;)

JayDawg
12-28-2007, 10:22 PM
I just got some Bilstein 5100's for Christmas. I am wanting to set them at 2.5" which is the max lift availible that way it levels out my truck from the rear leaf tsb. Do you all think I will have this same issue?

SP!N4L T4P
12-28-2007, 11:19 PM
Dont go to All American 4X4...unless you like to get RIPPED off...MMM KAY? ;)

here here!
:xbeer1:

AxleIke
12-29-2007, 01:55 AM
I just got some Bilstein 5100's for Christmas. I am wanting to set them at 2.5" which is the max lift availible that way it levels out my truck from the rear leaf tsb. Do you all think I will have this same issue?

Not on a brand new truck.

If you have worn out parts on that baby, you need to take it in to the dealer and call bullshit.

You will be fine.