Need help diagnosing Front end clunk

[HRTROB]

Hey guys, I need your help because I am completely stumped. I cannot seem to find the source of my front end clunk. There is a clunk when entering driveways or going over speed bumps. It started clunking after wheeling her 2 weeks ago.

I have a 96 HDJ80, 5 MT and part-time 4WD. OME medium lift, OME caster correction bushings, OME adjustable panhards, manafre coil spring spacers, manafre sway bar drop brackets. These suspension components are less than 2 years old. Last year I had the front panhard upper bracket welded because I noticed a tiny hairline crack. Last week I replaced the sway bar bushings as well as the sway bar link bushings. Rear U-joint was replaced last year.

While underneath the car I was banging on the suspension components with my hand and the only part making some noise was the steering drag link. The ends would easily rotate but there doesn't seem to be any side to side play. I do not feel any vibration in the steering wheel at all.

What do you guys think?

 

[PZLCruiser]

Same thing drove me nuts last year, like yours was a fairly fresh suspension. I noticed the front sway bar bushing would easily get deformed when flexing on trails, the disconnect setup is a good idea. I haven't done it yet, it's on the long list. But what I also found was that my steering column locking mechanism was loose and it would feel like a front end knock but was right there the whole time. There's a good write up about tightening it. Go jump in the truck and see if your steering wheel moves up and down. If it's loose you'll know right away and feel the play.

 

[HRTROB]

Thanks for the input. I've checked the steering column and the locking mechanism is still okay. What I did find was that the steering column "main shaft seal" that goes to the firewall is torn but I've insulated it with some padding in the mean time while I wait for the new part to arrive. The clunk is definitely from the front and underneath of the car because it is louder with the windows down. I had a friend listen to the clunk while I drove the front wheels back and forth on the driveway ramp and he said that it was coming from the bumper (I have an ARB winch bar and side rails). He was holding the bumper when I drove it back and forth and whenever it clunked he said that he felt it in his hand. I've retightened all the bolts, none were loose. It could be something else clunking and resonating in the chassis. Again, I'm stumped!

 

[SammyT96LX450]

Check your front control arm bushings and your exhaust brackets/bushings That was the source of my clunk when I was diagnosing mine. I replaced all of those along with my panhard bushings. No more clunk. Good luck.

 

[HRTROB]

Check your front control arm bushings and your exhaust brackets/bushings That was the source of my clunk when I was diagnosing mine. I replaced all of those along with my panhard bushings. No more clunk. Good luck.

Front control arm bushings are relatively new (OME caster correction bushings) except for the ones that connect the control arm to the frame. The OME adjustable panhards I installed also came with poly bushings

 

[SammyT96LX450]

Front control arm bushings are relatively new (OME caster correction bushings) except for the ones that connect the control arm to the frame. The OME adjustable panhards I installed also came with poly bushings

Check the ones by the frame.

 

[HRTROB]

I took the truck to a mechanic today to see if he can find the source of the clunk. He retightened all the nuts and bolts underneath, then he told me that two of my front passenger side lower knuckle studs have sheared off. I'm not sure if they sheared because he overtightened the nuts, or if they already sheared from loosening up. Wouldn't the studs fall off if they were already sheared? His reasoning was that the knuckle and studs were caked in thick mud (they really were) preventing the studs from falling off. Could this be the source of my clunk?

 

[inkpot]

Those knuckle studs gotta get fixed ASAP! Search this forum for multiple entries related to this failure. IF that does not cure your clunk, insure that your mechanic TORQUED the radius arm and panhard bolts to 130 pounds. Tight won't hack it in the long run.

 

[82much]

I am having sort of the same issue but mine only clunks when reversing with my wheels turned towards the passenger side. It's driving me nuts.

 

[hobbes]

Birf?

 

[richardlillard1]

I am having sort of the same issue but mine only clunks when reversing with my wheels turned towards the passenger side. It's driving me nuts.

Is it a clunk or a repetitive sound? My tires were tapping against the front locker harness, so check that?

 

[richardlillard1]

Like @inkpot said, fix the knuckle studs. If they sheared, there are several possibilities.

I heard one of my front studs snap as I pulled into a water crossing in Utah back in March. The stud wasn't completely sheared, but snapped right off when I decided to check the knuckle studs on the side of the trail; a tiny little piece of the stud was holding on for dear life until I applied pressure to it. This kills the stud. Same thing might have happened to yours. I usually check mine pretty often, but I forgot before that trip and then paid the price. Ultimately, I finished the next six days with only three studs on the passenger side. Still have the stud, if anyone wants to see it, I can get it out of time out for a photo op.

Buddy of mine also lost all of his studs while on the trail leaving the knuckle held on by the upper trunion bearing assembly. That was a fun night with unexpected camping in the front seat of my rig in the middle of the trail, staring at his. I also bled a lot that weekend (long story).

Another buddy of mine lost two out of four, trashed the inner axle seal, needed a spare front bumper bolt and a whittled piece of wood to get the truck off the trail in what became an unplanned night run. @inkpot and @Tools R Us probably don't want to repeat that one. I sure as hell don't.

Different buddy paid to have a shop rebuild his front axle before a trip to California for the summer. Shop guy didn't know his s*** because ALL of his nuts on both sides were several turns loose. Damn thing probably would have come apart on the highway with it that bad.

And most recently, I climbed under my buddy's truck (thankfully while it was in his garage) and noticed a small line of grease between the steering arm and knuckle starting to form. Got out the torque wrench and all of them were loose. One on the passenger side (same one I broke, I believe, so likely the most strained spot) was even a few full turns out.

So fix that s***. And check the torque on them regularly.

Also, I've had clunking in the front end before and it turned out to be a radius arm bolt that was loose after replacing my arms. So while you're under there, reset it from 71ft lbs to 130ft lbs and check those.

 

[HRTROB]

Yup, definitely going to get it fixed ASAP! Had to limp the car to my parents' house which was just a couple of miles from the shop. The car is staying there while I wait for the Toyota dealer to get the studs from their depot on Monday. I'll fit the Toyota ones just so I can use the car while I wait for the ARP studs from the US to arrive. I'll take a couple of photos later of the broken studs.

 

[HRTROB]

Here are the sheared studs. I'll let the dealer fix this one

 

[mikaelrules]

OT: You drive a manual, part time 4WD HDJ80? Where are you from?

Like others have said, check the bushings on the control arms by the frame. I had the exact same clunk as yours (speed bumps and driveways). Took apart the control arm and found this. (new bushing on the left)

 

[inkpot]

Yup, definitely going to get it fixed ASAP! Had to limp the car to my parents' house which was just a couple of miles from the shop. The car is staying there while I wait for the Toyota dealer to get the studs from their depot on Monday. I'll fit the Toyota ones just so I can use the car while I wait for the ARP studs from the US to arrive. I'll take a couple of photos later of the broken studs.

Dont really see any particular reason the ARP studs would be any better than the OEM. Failures have virtually all been due to lack of maintenance, not quality of parts. Kinda like lug nuts and caliper bolts, its a really good idea to check them occasionally with a torque wrench, especially if you wheel hard and/or run 35/37 inch tires. Don't know of any that were well maintained that failed.

 

[HRTROB]

OT: You drive a manual, part time 4WD HDJ80? Where are you from?

Like others have said, check the bushings on the control arms by the frame. I had the exact same clunk as yours (speed bumps and driveways). Took apart the control arm and found this. (new bushing on the left)


View attachment 1298309

I'm from the Philippines also kabayan

Thanks for the heads up. I'll go ahead and replace those bushings since they might be toast.

 

[HRTROB]

Dont really see any particular reason the ARP studs would be any better than the OEM. Failures have virtually all been due to lack of maintenance, not quality of parts. Kinda like lug nuts and caliper bolts, its a really good idea to check them occasionally with a torque wrench, especially if you wheel hard and/or run 35/37 inch tires. Don't know of any that were well maintained that failed.

I was thinking that the ARP ones are stronger and are less likely to shear in case the nuts loosen up? I'm only running 33s. I never bothered to retorque the knuckle studs, from now on I'll be sure to check them before and after wheeling

 

[richardlillard1]

I was thinking that the ARP ones are stronger and are less likely to shear in case the nuts loosen up? I'm only running 33s. I never bothered to retorque the knuckle studs, from now on I'll be sure to check them before and after wheeling

There's a lot of forces in that area and while the ARP kit calls for loc-tite (on the stud only, which sounds like a good idea on the surface, but is a bad idea in my opinion, for multiple reasons), all it takes is the nut coming loose to screw things up and shear off whatever stud is there.

Besides, a torque wrench is something you should already have, so taking the time to get under the truck and torque them every few months is probably a good idea.

 

[richardlillard1]

Keep those nuts, flat washers and cone washers. They're now great trail spares.