I just installed the fabtech 6'' with 37'' tires, I did feel a slight vibration when first accelerating,but now when Iam slowing from around 30mph to a stop (not on the brakes) I can here a slight noise. Almost like a bad wheel bearing.The noise sounds like it is coming from the front left. I have had it to the dealer and first they said it was the clutches in the rear end, so they changed the diff fluid( $285.00) no difference. Then they said my front drive shaft was at too much of an angle, and the U-Joints are binding. I looked at the Frt. drive shaft and I can't see any way it is binding. If anyone has had this prob. after lifting theres please let me know. Thanks
( DAMM THESE 37'S TAKE AWAY ALOT OF POWER)

 

I had the same problem with my old f250. it was the diveshaft angle,but the fabetech is really about 5" of lift so it sould'nt be binding. Jack it so the front tires are off the groud and rotate the driveshaft to see if its binding. If it is Try www.arizonadrivelines.com they lengthend mine and added a high angle cv for pretty cheap. It probably is your rear carrier bearing needs to be shimmed. That is the problem most people have after lifting a long bed.

 

I thought the rearend in the 3rd gen trucks didn't have clutches....

 

Why dont you just remove the front drive shaft and see if the noise/vibration goes away.

Sorry to hear about your $300 gear oil change

I'm also afraid to go with a 37" tire. I have 35" Toyo's on 18's but I want to step up to a 20" rim but that means if I want to keep my rim/tire ratio the same and avoid the low profile tire look on a lifted truck I will have to also increase my tire to a 37"

I wish there was someone near me that has some 37's that I could test out because I drive on mountain roads alot and also like to speed on occasion and drive it like it was stock.

 

I did jack up the truck and there was no bind. The only other thing would be the angle, and I did rotate the tire and there is no noise or wobble,but they are rather hard to rotate. I think its becouse it is full time 4x4.As for the 37's, I have 3:73 gears and think I'am going to jump to 4:56.I can still boil the 37's but I miss the way it used to pull on the freeway from 70mph and up.

 

Mine was binding with my 4.5" lift. I could not tell by jacking the truck up and spinning the d-shaft. It binds up in the h-yoke, it's hard to see. You may hear a clunking noise when slowing down. Like SlowSixSpeed said, the best way is to take the shaft off and see what happens.

Most all longbeds need a carrier bearing drop, that is what usually causes the vibration on takeoff.

 

hey greyghost,
try shiming the carrier bearing on the driveshaft down with a piece of 1" square tube . that fixed mine on my f_350 might have to play with it alittle . but vibration comes from driveshaft agle.

 

Superlift carries spacers to drop the carrier bearing down, as well as a indexing ring for the transfer case, both of which are needed with a 6" and higher lift...

 

Thanks for the info.I did see a little wear mark on the H yolk,I was told that taking a dremmal and clearancing it a little should fix it. as far as the shutter when accelerating, I did not touch the rear of the truck other than putting the 37'' tires on. But my carrier could still be bad.

 

So you lifted the front 8" but didnt lift the rear at all?