Front Drive Shaft grrrrrrrrr findings so far. .

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Tools R Us said:
Your going to be in, CV shaft for the front axle and for the rear axle, longer lower and/or shorter upper rear arm, land. :D
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I think I'll manage w/o-especially the rear shaft... :confused:

and/or shorter :confused:

Don't "need" longer lower arms. I would then need to relocate the frame bracketry to avoid rubbing.

I think as ActionJackson is getting away with 6+" of spring lift and upper arm correction-I'll be fine with less than 6" of lift. And w/ lift upper arms would ALWAYS get longer unless dropped to stock geometry.

I'll likely end up with a situation where the CV shaft isn't happy anyway Ol----lP
 
As for the rear arms, does anyone know if the caster bushings will press into the bushings on them. I was thinking that a set of 4 bushings pressed in at opposing positions might be an easy way to rotate the rear shaft a little to help out with vibs back there and still keep it centered.
 
Just thought I would post some info on this subject.

The angles of your U-joints(pinion/driveshaft and t-case/driveshaft) need to be within +/- 3* of each other.

If running a DC shaft you need to be within +/- 1* on the pinion/driveshaft angle, and it does not matter(to a point) what the angle is on the t-case/driveshaft angle.

Now here is my experience. I have installed OME lifts and have notice that when a heavy, and sometimes a medium duty lift is installed, the rear of the vehicle in relation to the front is higher than the same relationship in a stock configuration. (ie. stock 19" to frame rear 20" front, lifted 22" rear 22" front.) This means is that the pinion/driveshaft angle increases and the t-case/driveshaft angle decreases.

The only way to solve this angle issue is to; one, rotate the pinion down to match the driveshaft/t-case angle; two, lower the rear crossmember mount under the trans/t-case to match the pinion/driveshaft angle; three, run a softer set of springs(in the rear) to decrease the overall height of the rear of the vehicle; or four, carry a lot of payload like OME states per type of spring ordered, this will lower the back end and therefore put the angles back to specificationis.

The front angles are usually corrected with castor correction bushing that can be ordered with the kit, but if the angles are off, the same does apply with the front as does the rear.

Don't discount the rear driveshaft as a possible problem. The sound from the rear will resinate through the cab causing it to be impossible to pinpoint which is vibrating, also since they mount to the same location(the t-case) the sound realistically could be comming from the same location.

Check the angles on both the front and rear of both of the shafts and compare. Post the results, I would like to see what the angles are at. If some one would like to check the stock angles, for comparason, and post them that would be great as well.


I hope this helps

Scott
 
Well, here is where i am now and i guess where i'm going next:

Things i have done to eradicate this fawking grrrrrrrr.
1. Removed front shaft – resulted in the grrrrrr going away.
2. Put new U-joints in the front shaft – resulted in no change.
3. Had the front shaft balanced – resulted in no change.
4. Had the front shaft shortened one inch – resulted in no change.
5. Ground the leadings arms where the tie rod was touching on them. Now the tie rod does not touch – resulted in no change.
6. Drove with the shaft in phase – resulted in no change
7. Drove with the shaft out of phase – resulted in no change.

So, I guess the only option I haven’t tried yet is the double cardan shaft.
 
Concrete,

Thanks for keeping up with this.

Have you eliminated the T-case output shaft and pinion bearing.

Also, if it helps, here are my findings with the GRRRRR.

1. Lifted 80 2.5 inches....GRRR shows up
2. All new U-joints(Front & Rear)- No change
3. Add 100 lbs to front of ARB- GRRR seems to go away
4. Add 100 lbs to rear on cargo area- No change
 
sleeoffroad said:
How sure are you that you only got 2.5" and not more? How much lift did you get in the rear?
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Good point, they are all heavy load springs so it could be more. I did however, get the springs used so im sure they had already settled some.

But hypothetically speaking, lets say i got more...like 3 inches. What would this mean? Would it give reason for a DC shaft?
 
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christo, i'm not totally sure i got the medium lift, i did purchase it from you, so i'm pretty sure i got the right stuff. The boxs the springs came in i used to mail my stock springs to lowtide, so i can't double check the numbers on them.

Here is a pic of my lift. FIrst is back, then front. No bumpers, just sliders and a roof rack. Measurement is from center of hub to fender.
lift height 001 (Small).webp
lift height 002 (Small).webp
 
Cruiserhead05 said:
Good point, they are all heavy load springs so it could be more. I did however, get the springs used so im sure they had already settled some.

But hypothetically speaking, lets say i got more...like 3 inches. What would this mean? Would it give reason for a DC shaft?
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Our experience is that in the 3"+ range, you can expect these vibrations and issues. Adding weight and it changes the situation points to the shafts. Given that you replaced the U joints, I would say a DC shaft is the way to go. Anyone close to you that you can loan one from?
 
sleeoffroad said:
Concrete, have you done the weight test?
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No, i don't have an ARB to strap anything to. I have a big bag of pea gravel i may try to strap it on the stock front bumper this evening when it's dark out and give it a whirl.
 
concretejungle said:
to. I have a big bag of pea gravel i may try to strap it on the stock front bumper this evening when it's dark out and give it a whirl.
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Be sure to take a pic of this....strictly for our amusement :flipoff2:
 
Concrete.....do one thing though, which i failed to.
Take the truck out and drive it until it start the grr sound and then come back and add weight. I'm fairly sure 90lbs of bench weights helped mine a ton but i cant be 100% sure b/c i only drove it for 10 minutes.
What i did was take a luggage bag and through all the weights in there, then used to ratchet straped to hold it on.

If i could find some way that find out if the DC would DEFINATELY cure my problem, i wouldnt even so much mind dropping the cash for one b/c i know if i go with a 4 or 6 inch, i will need it anyways.

Plus if i dont want to swing the full 380 from slee i can sell my old front shaft with new u-joints for a little to help balance the cost.
 
OK, now that I have found this thread, I will resurect it, and ask again :D . Why do I get grinding vibration in the cabin floor, under my feet, driver side, only when going over 60 mph, some times at 55 mph? I have 3" drop brackets. I never had any vibration like that after I installed my lift, it started happening after a wheeling trip. My tie rod does not touch front lower control arms, rather far from touching it. What do ya'll think is the problem?
 
Riad said:
OK, now that I have found this thread, I will resurect it, and ask again :D . Why do I get grinding vibration in the cabin floor, under my feet, driver side, only when going over 60 mph, some times at 55 mph? I have 3" drop brackets. I never had any vibration like that after I installed my lift, it started happening after a wheeling trip. My tie rod does not touch front lower control arms, rather far from touching it. What do ya'll think is the problem?
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Check your driveshaft for missing weights and any damage. A vibration that starts after a wheeling trip indicates damage or a wear item that was pushed out of normal limits.

Nay
 
Raid, if you have one built, usually when they balance them if they are off just a little then they will weld itsy-bitsy tabs on them to balance.
 
Mine is stock drive shaft. Can stock drive shaft be off/out of balance? I crawled under and spent 45 minutes, trying to look for damages, loose parts. None. I can't move the neither front or rear shaft with my hand. I should mention, after a wheeling trip, I do check for anomalies such as loose wheel bearing, misalignment, etc.
 
Cruiserhead and Concrete

Anything new on this?

Did you solve your problems?
 
driveshaft vibes

Yeah, the 80s will get the growl out of the front shaft over a couple of inches. Both mine did it with J's and a bullbar/winch/wieght. In fact, my 96 would get it in the back with J's and limited wieght. Even with adjustable arms, I could not get rid of it on the rear shaft if I was above 4" of lift.
 
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