Axle wrap or tranny mount?

I just installed a Aussie in the rear of my '99 w/6.5" of lift. The previous owner installed 3" block, a shim, extra leafs, and a 1.25" shackle. I recently noticed that when accelerating maybe 1/4-1/2 throttle out of the hole I get a horrible grinding noise. Sounds similar to extremely grooved rotors. I can feel it and hear it all over the place. I'm going to be getting rid of the blocks and going w/a full leaf pack. Is this from axle wrap or would the trans mount be more than likely the culprit? The motor mounts are about a year old. I did notice before the locker that if you were to kick it down to first at speed there would be a hard clunk underneath, so again hard to say if its axle wrap or tranny mount related... What do you guys think?

TIA,

Sean

i was experiencing terrible axle wrap at 3" AAL'd rear, 31's and an aussie, i cant imagine with a 3" block/aussie combo! i didnt experience a grinding noise, but who knows?! If i floored it in dirt, i'd get a sensation of both rear tires kicking like a dog when you scratch it's belly just right. its terrible, and bad for driveline/shocks!

if you think you have an axle wrap problem, you do!


i replaced the AAL with RE 3.5'' leaf's, and havent had it sinse!. very happy! at 6" you need more work, maybe do a shackle relocation bracket, a lift shackle and like 3.5'' leafs. needless to say, that block is the culprit, and your new found traction is like throwing gasoline on a brush fire.

Check your u-joints!

It is still running a stock front DS as well. I'm almost wondering if its getting to be too short for the amount of lift that's in there. Anybody know how high you can go and still use the stocker front in the rear?

If your '99 is really at 6.5" of lift, you should have addressed the rear drive-line operating angles. The front u-joint (assuming you have a double-Cardin rear shaft installed) is probably approaching 16* even before any spring wrap. And I can't imagine you don't have spring wrap. So you're probably getting all kinds of shaft harmonics.

That's what I was wondering is how much of a lift you can get away with before needing a new DS. Or am I at that point? I did measure the front and rear from axle hub center to fender flare and they are at 24.25" front and 23.50" in the rear. Going off the stock height of 17.50" front and 17" rear that put me at 6.75" front and 6.50" rear. Buying some 5.5" leaf packs this weekend from IRO. That coupled with the 1.25" shackle (probably leave the shim in as well?) Should put me right at level with the front.

With the shim in there the pinion angle doesn't look half bad. I've seen worse but am wondering if maybe the DS is too short? Should also add that I have no driveline vibes even at 80. A little when letting off the throttle but nothing bad.