Front end noise, input please?
 

Hey folks, curious if anyone has a better/deeper understanding than my garage, about these vehicles in particular.

This Spring, Sophie the '96 4Runner, got new, OEM LBJ's, bolts etc. Just gave her new front axles since both CV's decided to die rather spontaneously. Had the tie rod ends checked at that time, no play. Also had an alignment done (discussed on here at length already), my caster cams are frozen, but were close enough for government work, and the truck drives fine.

My plan is to do them next year (big, $$$ job), and that will also include lower control arm bushings getting replaced.

I do not understand the mechanics, or physics, of vehicular front ends. At, all.

These parts, are also just names to me, I don't get how they work, nor am I asking for an explanation of that.

The problem is this:

When I brake, firmly, to a stop? I feel a decided *thunk* under my left foot. Upon releasing the brake, and starting to accelerate, I feel it "release", and *thunk* again.

Tight, low speed turning, with some suspension activation, (say, turning into a driveway with some potholes in the immediate mix), and get a similar thunking.

My garage that did the axles (and most of my other work) checked it out, confirmed all fasteners are properly snug. They were able to recreate it themselves, and feel it, and basically, kinda shrugged and said, everything is tight, and fresh, I wouldn't worry about safety wise, etc.

Basically, "wait till it's so ugly we can see something, and then we'll fix it."

So, are my LCA bushings, pretty much the only other thing left that moves up there, and it's likely them, and then yes, it's a non safety concern that'll resolve itself when I replace the caster cams etc?

Or is there more stuff, and I should be asking for a more in depth check over?

She's been a street queen since birth, and under my ownership too, and has never been abused off road if we venture off, but she did have a front end meet up with a concrete highway barricade afew years back, so the back of my mind is going, "broken frame, etc???".

Thanks!

Greasing the drives shatfs might help.

Grease your rear drive shaft at the zerk fittings. There's little ends on the shaft (a few for 2WD, many for 4WD) that you attach a grease gun to. You'll see a tiny little check ball that closes the valve except when under pressure. Then pump in grease until you hear a crackly noise as the grease just barely starts to seep out, then stop. If you put too much in, get a small metal screwdriver and press the ball bearing in and allow grease to shoot back out until it stops. The most important one is the slip joint where two parts of the rear driveshaft move in and out. When it's greased, this works seamless and quiet. When it's dry, the metal components clunk when they compress or expand. Braking and accelerating causes this expansion and contraction. If yours is dry it will seem like you are pumping the whole tube in there. This is normal and keep going until it fills up.

I recommend a pistol-grip grease gun with your standard Moly grease that is dark grey in color. Others use different kinds of grease. It comes in a large tube that attaches to the grease gun. If this seems too intimidating, you can have a shop do it but the labor costs will not be worth it in my opinion. Takes no tools except for the above mentioned grease gun.

Thanks for that, both of you.

I'll absolutely check that, but I'm also assuming that a decent shop would do that during a typical "lube oil and filter"?

Perhaps not, I definitely can't say for sure it's ever been done...

Would that manifest itself in a feeling literally under my foot, though? Not arguing, more baffled, but in bicycles (my field) I know that sounds can broadcast great distances from the source, so I imagine physical actions can too.

It's just that "rear drive shaft" sounds very far from where I'm experiencing it!

a "good" shop might not know all the spots on the 4 runner drive line to lube....off the top of my head I think there are 5 or 6 just on the rear drive line

Roger that. Thanks, I shall inquire with those guys. Appreciate it!

You would think right? Greasing the driveshaft and changing the differential and transfer case oils are two of the most neglected maintenance items on a 4WD vehicle. Only dealerships will pay attention to these spots, IF you ask them to but you'll pay a lot for it as well. Your average shop won't even look at it much less spend time or labor on it.

You'd be surprised at how sound travels. Because we have an open rear hatch and not a trunk, sounds in the rear will travel in a way that it sounds much closer. Plus the driveshaft is connected to the transmission so sound and vibration will travel up the solid metal and the transmission is right under the glove box so it sounds quite close. One of the few griefs I have with these 4Runners is the lack of sound deadening in the rear hatch area, there's so much road and tire noise that comes from the back.

Just because I'm a detail oriented person?

This is not a sound, you barely hear it.

I absolutely FEEL it, right under my left foot.

Not discounting this theory at all, I like it.

Would that thunk from the driveshaft, out back, transfer all the way up and under my foot, even though it's in 2WD not 4? 4 would make sense as everything was coupled, and moving as a unit.

But again, I really don't intrinsically grasp all the mechanical interconnectivity of these systems.....

Still need to stop at my shop, I'm so curious, since they're a small, local, independent shop that's been owner operated for over 50 years, and both father and son are gearheads of the first rate,

That sounds like lower control arm bushing is worn. I think I know exactly what you're talking about in regards to the thunking, every time I've run into that it was LCA bushings gone out. Or loose LCA bolts, but you said yours are snug.

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All of my front-end clunks and thunks have been caused by sway bar end links. Easy to replace and if they were worn, bent, or loose, you will have a better handling experience.

Or the bushings where it clamps to the frame. On my 96 the passenger side was gone and it thumped bad on the test drive in north Philladelphia.

I questioned the guy on the noise cause he actually said no noise and his reply was I was talking about the engine.


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Yes, check those bushings, too. I did both links and frame bushings and it really tightened things up, klunk-wise.

Okay, so there are other clunk makers in front, I assume none of those are immediate danger spots? I was told the LCA bushings are not.

I did stop at my shop and they confirmed, yes, they do hit all grease fittings on the driveshaft during a standard oil change.

He followed it with, "yeah, Toyotas are one of the few vehicles that actually HAS grease fittings on the driveshafts still", which made me feel like they are the good shop I feel they are....

Sounds like you've got a great shop that you go to and are very thorough. I would stick with them for as long as they are in business.

Check the other bushings that others are referencing and grease, tighten, or replace to see if it eliminates the noise. The sway bar bushings and end link bushings up front would be the easiest ones to start with. I recommend poly bushings from Energy Suspension if you choose to replace them, they are fantastic and better than the stock rubber bushings in controlling body roll.

I'm back!

Sophie cam out of storage and basically went straight to the shop.

The good news? My bill was less than expected. They were able to free up and remove, clean the crap out of, goop up, and reinstall my caster adjustment cams, without replacing them.

Fully tested the LCA bushings, and they didn't even look worn, let alone, act worn.

So now? New JBA UCA's, new LBJ's last year, torsion bars have fresh bumpers, bushings, whatever the rubber stuff on em is that crapped out, full alignment to proper spec, new axles/CV's last year too.

Thing drives like a million bucks, and with the JBA's and fresh alignment, the rubbing at the back of the wheel well is gone, even with these 34" Mickey Thompsons.

Overall, I'm thrilled.

But, my clunk persists.....

When turning, up into, or down into any place that has a dip from level and back again, think concrete drainage swales, etc. One clunk, then another if the process is repeated in reverse, so, set, reset.


Spoke with my mechanic, (after telling him how amazing it was driving now), about it, and he's stumped. Like me, he said, "well, pretty much everything in the front end is either brand new, or freshly inspected, serviced, and working like it should, so WTF?

His only thoughts lie in the 2" OME suspension lift, coupled with the 2.5" spacer lift (to level the front end, but it overshot, covered elsewhere) is somehow straining, or exceeding the limits of the remaining OEM parts.

He suggested removing the front driveshaft to test it without the front end being connected and see if it changed anything (process of elimination test only).

I now have found a local offroad mechanic/fabricator who I plan on visiting in the next month or so, so he can lay eyes on this haphazard project and help me develop a plan to optimize function. I know I've plugged weird crap in not understanding what I'm doing, and I want to stop that, now.


Thoughts? Overextended drive shafts, stock linkages stretched beyond their range? I'm clueless and frustrated....