I've searched this forum and many others and have found a few similar situations, but nothing exactly like mine. I have a 2003 v8 sport. I replaced all ball joints, sway bushings, inner and outer tie rods, installed fj coils front and rear, bilsteins up front set to 1.75, bilsteins in rear, 1.5" daystar rear spacer, firestone airbags, new napa cv joints, spidertrax 1.25" spacers (checked torque 2x since install) and new 265/70 r17 BFG AT KO. The tires were balanced and front end aligned. I also greased all the driveline zerk I could find. I'm going to reaccomplish this today thought just to be sure.

I am getting driveline vibration on acceleration from 55-65 mph. If I let off the pedal it goes away. It doesn't do it at any other speed or while braking. The vibration does not change if I turn while accelerating. I feel it in the steering wheel (not a side to side shimmy like out of balance tires but a steady tight vibration), pedals, and a little in the seat. It will do it in 4th and 5th gear so I don't think it is the "rumble strip" issue. I can't really pen point where it is coming from.

I don't get any clunk when shifting from P to D or any other gear selections so I can't 100% say it is a u-joint. I'm leaning towards u-joint going out or a bad pinion angle after the lift.

Side note. When I back up and turn the wheel to the left I will sometimes get a clunk in what sounds like the front end. I can't teproduce it everytime. Maybe 50% of the time. I've had the front end apart 3x looking for anything odd.

Things I plan to check.

-u-joints
-differential mounts for cracks
-cv shafts
-steering rack attachment points


Any other ideas?

Forgot to say I also installed light racing UCAs

I don't know anything about lifts or how they would cause or amplify this sort of problem but my guess would be either a u-joint or an unbalanced drive shaft. Either one could cause the vibration that you are talking about.

Good luck.

I think I found the source of the front end clunk. I replaced the LCA bushings with Moog parts. Looks like the bushings has pulled out of the LCA bore. I'm guessing the bushing is a little undersized or the bore got oversized when I popped out the old ones. I had to use a bottle jack and a torch to get them out. The moog bushings have a shoulder that is about 3/8" long that is the press fit diameter. The rest is undersized. I think if the shoulder were longer it wouldn't do this. I don't remember what the OEM looked like. I might have get a completely new LCA.

This is my DD besides a sport bike. I guess I'll order a new LCA to replace this one the measure the bore of the old compared to the bushing. Dang it.

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U-joints checked good after pulling drive shafts. One was ever so slightly stiffer in one direction compare to the rest, but I don't think it is enough to matter. I cleaned, greased, and installed the shafts again.

I plan to swap the lca and cv for new ones. I put in an old cv to see if the new one had fitment issues, but it isn't the cv. After that, it will be an alignment and test drive. Hopefully it will cure the clunk and improve the vinrations.

After that if the vibes done go away I might try having the tires balanced on a hunter machine with the right adapter. But, I highly doubt this is a tire issue because it is only during acelleration. If that doesn't cure it maybe a diff drop will help. Beyond that I don't know what to do. Ugh#

I wish you luck. I had a vibration at 40 mph after installing the daystar leveling kit. I believe it is a needle bearing in the front diff that doesnt like the cv angle on the drivers side. it only happens at 40 mph then goes away. Yet if I go into 4hi it goes away since everthing in there is locked up and tight. I hear there is a fix for it that involves getting rid of the needle bearing and replacing it with something else. It looks like a common problem with taco's.

That's strange that yours goes away when locked up. Mine is a v8 so it is always in 4x4 and I have the vibes.

East Coast Gear Supply sells a bushing to replace the needle bearings.

Great info. Thanks!

I looked for it and found this.

http://eastcoastgearsupply.com/i-853...l-bushing.html

It specifically says it doesn't fit AWD (V8) 4runners. Damn.

Thanks for the ideas guys. Keep them coming. We got over 5" of rain today so I can't make much progress working in the driveway today. It's flooded out! I ordered a new LCA today. As soon as it comes in I'll swap it and the old cv and cross my fingers.

More to com.

The ECGS bushing is a solution to a very specific vibration caused by a the driver side differential output shaft needle bearing not doing a good job supporting the CV shaft. The classic symptom is a low speed vibration (often 20mph or less) that goes away when you engage 4wd. It can get bad enough that engaging 4wd won't make the vibration go away, however. If you don't have that very specific problem, it won't help. It definitely won't hurt though.

If you don't have excessive slop on the inboard side of the driver side CV shaft (where it goes into the differential) then it's unlikely that the ECGS bushing will help you.

I have one in my 4Runner. It's an easy install and it did help. It's not a magic bullet though. I installed one in my 1st generation Tacoma too and it didn't help at all.

Glad you seem to have figured it out. I have a 3" toytec ultimate with UCA's on my 06 4x4 and I get the clunk in the front, similar to what you have described. I have not had the chance to inspect much, but a dude from Toytec told me that it could very well be a loose sway bar or the sway bar bushings are going and the coils are smacking it. He also recommended a sway bar relocation kit, which toytec sells.

I completely removed my sway bar for a few days and still got the clunk. Take yours off and drive for a few days and see if it repeats. If it does you know it isn't the sway bar.

The vibrations seemed to have gone away today. I exercised the center diff lock a few times on some 30-45 mph straights and now it doesn't vibrate between. 55-65mph under acceleration. I wonder if it didn't completely disengage when I used it on some dirt roads last week? The biggest thing I went through was a 16-18" vertical lip. I used 4 low and crept up it.

More to come as I continue to daily drive and diagnose.

Thanks for the input, but ECGS specifically states it does NOT work on V8 all wheel drive 4runners. I have a V8 all wheel drive. Look a few posts back to the ECGS link I posted and read the description on their page.

Not trying to be rude. I just don't want someone to read this later on, order the bushing, installation tool, etc and then see it doesn't work on their AWD V8.

Turns out the vibrations were because the center diff didn't unlock all the way. After engaging and disengaging it a couple times the vibrations went away.

I replaced the lower control arm with a brand new one. It came with the bushings and the ball joint installed. I switched back to the new cv axle, buttoned everything back up and went for a spin. I thought the clunk went away, but I pulled through a sharp slow turn and CLUNK! Only thing I can think of now is the moog fj spring on the back might be shifting on the perch. I've gone through everything in the front end.

I'm at the point that it will just have to clunk until it falls off.

I changed out the driver side cv and put new strut plates and rubber washers on the struts. It still goes clunk on sharp left turns and over sharp bumps while braking. Nothing in the front end shows signs of wear other then normal use.

The only thing left I can think of its the steering rod going up to the steering wheel or a motor mount. I'm at a loss and might have to take it somewhere.