Thunk Noise - Opinions Please

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Telly

Telly

10 Year
Joined
Apr 1, 2013
Threads
16
Messages
71
Location
Monument, Colorado
03 100 Series with 153,000, owned for 1 year. The two scenarios where the faint/dull thunk noise occurs (but not every time) are: 1. Releasing the brake at full stop, immediately hear/feel thunk from rear driveline area. 2. Upon slow acceleration, hear/feel thunk within a second of starting momentum. No noise with hard acceleration. I was convinced it was from a sticking rear brake caliper. Still occurs after new OEM rotors, pads, greased caliper pins, and inspected calipers. I have greased the driveshaft and u-joints but will be replacing the u-joints as a PM soon. Replaced the rear diff fluid with Mobile1 75W90. I checked for loose suspension components (none) but I'm planning to install the OEM medium 1.5 lift kit within the next few weeks (backordered). I'm hoping it's not a R&P or tranny issue. The sound is defiantly coming from the rear portion of the vehicle. Replacing the u-joints and suspension my cure it? Other thoughts/ideas I may be overlooking? Thanks.
 
Are you getting fresh grease oozing past the slip yoke seals? If not I'd keep greasing the front and rear slip joints 'till you do. A few pumps on each slip zerk every other day until fresh grease starts to ooze might be the simple and inexpensive fix.
 
That's all it took on mine.. Same thing with my 4th gen 4runner.. Good luck.
 
I had to pull both drive shafts, clean the old grease out of the splines and re-grease. Got to add a ton of grease directly to the splines before putting them back together. Take out the zerk to slide them back together or it acts like an air cylinder. My clunk/thunks didn't go away until I did this.

Tip: impact gun might be needed to get the bolts loose if it's the first time. Use the proper torque values from the FSM when tightening them back up.
 
I think I saw in one post on this issue (may have been in the thread linked in the FAQ) that too much grease pressure can damage stuff - like the transfer case. How much grease is too much in the slip yokes? Or, how much grease pressure or how much can you force the drive shaft to extend? I was adding some last night and I stopped when I saw the drive shaft extending out of the slip joint. I still have a clunk so I am wondering at what point do I tear it all apart, or just keep adding grease?
 
Update: I have pumped grease into the front and rear slip joint zerk on three separate occasions. I've probably pumped at lease 30 stokes in each zerk and still have not seen any evidence of grease oozing from the seals. The previous owner must have completely neglected these zerks. I will continue this process until I see oozing.
 
any update? I have the same problem.
 
I am two months in on my 100 ownership. I took it to Toyota and asked them to look at it. The mechanic reported no problem, he told the service tech there was slack in the driveline, and it is nomal? I'm not completely convinced.

Time to take it to Gary at Mudrack in Sonoma for a real eval.
 
phippsj said:
I had to pull both drive shafts, clean the old grease out of the splines and re-grease. Got to add a ton of grease directly to the splines before putting them back together. Take out the zerk to slide them back together or it acts like an air cylinder. My clunk/thunks didn't go away until I did this.

Tip: impact gun might be needed to get the bolts loose if it's the first time. Use the proper torque values from the FSM when tightening them back up.
Click to expand...


+1 for this fix.
 
Check your rear shocks. Mine had the same issue. After R&R of driveshafts, relube, etc... I finally figured it out when the shaft in the shock totally ripped out and was dangling.

You can always lock your CDL and drive with just front wheel drive to see if that does the trick, if so, you found your problem.
 
DJWUZJ said:
Check your rear shocks. Mine had the same issue. After R&R of driveshafts, relube, etc... I finally figured it out when the shaft in the shock totally ripped out and was dangling.

You can always lock your CDL and drive with just front wheel drive to see if that does the trick, if so, you found your problem.
Click to expand...


I have a '99 LX470 with 85k and AHC. I have the exact same issue that I have been chasing with the dealer. No luck. It almost sounds like a loose coil spring. It is not the driveline that is causing the noise, as it happens during steady state driving, not just accelerating, decelerating. Dealer thought it was coming from the coil and was all set to replace the coil springs on both sides, but took them off and they were fine. Im wondering now if it is a shock? How were you able to ID a shock problem?

Thank you for any info. This has been driving me crazy!
 
Wait until it completely unseats when headed toward the switch backs at Black Bear, waiting for something to give loose and go over the edge :) Yes, that happened, and you'll know it. The only way you can check that out is if you take the shock out completely. When we got to the bottom i could see where the stem was trying to shank the inner fender.

Do you know if the rubber seats are located at the top of the spring? That can cause some of it.

I'm not an AHC guru, but maybe someone here can chime in on it.
 
DJWUZJ said:
Wait until it completely unseats when headed toward the switch backs at Black Bear, waiting for something to give loose and go over the edge :) Yes, that happened, and you'll know it. The only way you can check that out is if you take the shock out completely. When we got to the bottom i could see where the stem was trying to shank the inner fender.

Do you know if the rubber seats are located at the top of the spring? That can cause some of it.

I'm not an AHC guru, but maybe someone here can chime in on it.
Click to expand...


Sounds like my failure is a little more, shall we say, progressive? Changing the suspension firmness setting seems to impact how often and loudly I hear the noise, so that is what has me leaning toward a shock issue. The dealer checked the spring perches and everything else and it all seemed ok, hence my frustration. I will pull the shock and see if it's on its way out. Thank you so much for the suggestion!
 
When you tweak your suspension, there are a lot of moving parts that move with it. I'd also check all of your bushings for your upper and lower control arms. Could also be sway bar links.

Grab a flashlight and poke around on those first.

If you pull the shock, get yourself a 22mm flex head gear wrench... best option next to cutting a hole in the floor.
 
DJWUZJ said:
When you tweak your suspension, there are a lot of moving parts that move with it. I'd also check all of your bushings for your upper and lower control arms. Could also be sway bar links.

Grab a flashlight and poke around on those first.

If you pull the shock, get yourself a 22mm flex head gear wrench... best option next to cutting a hole in the floor.
Click to expand...

Thank you. Unrelated I replaced the sway bar links after the noise started and poked around while I was down there. Shocks seem to be the only thing left. I have been avoiding them because I heard they were a PITA. Thanks for the tip on the ratchet.
 
Amendonsa said:
Thank you. Unrelated I replaced the sway bar links after the noise started and poked around while I was down there. Shocks seem to be the only thing left. I have been avoiding them because I heard they were a PITA. Thanks for the tip on the ratchet.
Click to expand...


DJWUJZ- A quick follow up. FSM calls for an SST to remove the top AHC shock bearing. Did you have to do this and did you find a non-factory tool that would work? Thanks in advance.
 
I've never done this before.. Any guides, I'd like to do this to mine.
Thanks.


...via IH8MUD app
 
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