Is it solely road speed dependant or does your throttle input impact it all like with u-joints?
Painful low frequency drone/pressure in cabin
- Thread starter LJE
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- Thread starter
- #262
I *think* it's all roads speed dependant. Going to spend some time on the road in the next day or two trying to rebaseline & recharacterize it after all the 'fixes' I've done.
I’m no expert on these things but is it possible that all the extra sound deadening you added is trapping the resonance in a certain part of the truck, or making it have a different frequency that is painful to humans?
Had to edit my earlier post as I had the bushing location wrong on the torsion bar crossmember. It looks like the 'support assy, front suspension' sits inside a frame crossmember. Appears the torsion bars and support assembly have to be removed to replace the bushings.
First pic below shows the support assembly with bushings circled.
Torsion bar adjustment below with bolt/bushing circled.
First pic below shows the support assembly with bushings circled.
Torsion bar adjustment below with bolt/bushing circled.
- Thread starter
- #266
Alright, update here.
Some observations (and no answers):
It's a good thing for this vehicle that I only found this after I put so much effort into resurrecting it. If I had less than $15K in it (I've got more than double that at this point with the lockers/leather/bumper/etc) I would roll it off a cliff.
Some observations (and no answers):
- It's definitely worse the higher outside temperature gets. That doesn't make sense to me, but neither does anything about this. Drove to work at ~0500 when it's 50 degrees outside - not terrible. Still there, but tolerable. Drove home at 1600 that day when it's 80 degrees outside and ow, my ears. So. Much Worse. This correlates well overall with my experience - terrible in the summer, better in the winter.
- It's better with more crap in the back. Loaded down for Cruisers on the Rockies, it was mostly tolerable. Some days on the road were worse than others, which is confusing.
- I ratchet-strapped the rear wing window mechanism to the floor D-rings to eliminate them vibrating the windows as a possibility. This actually changed things - rather than a 'pulsing' pain/pressure on your eardrums, it's now a constant pressure feeling - as if you were ascending/descending in an airplane but couldn't clear your ears. This would point to there being a pressure differential being created that was 'flapping' the rear wing windows, but with them ratchet strapped they can't do that any more; rather than a pulse you just get a constant pressure feeling on your ear drums. Still no audible noise.
It's a good thing for this vehicle that I only found this after I put so much effort into resurrecting it. If I had less than $15K in it (I've got more than double that at this point with the lockers/leather/bumper/etc) I would roll it off a cliff.
Wild shot here- What if instead of it being related to the ambient temp, it's actually something to do with whether you're running the heat or AC. Tried running with the HVAC off in the cooler/warmer duplicable conditions and seeing if the difference still exists?
This is really sounding like some sort of air intrusion/buffeting situation. How's the windshield seal/fitment? How's the sunroof seal? Window and door seals as well as rear hatch? Your last summary above makes me think that more air is entering the cabin than can escape the cabin...but from where?! The mention of the loaded rear made it better slightly......muffler tone or vibration?
- Thread starter
- #270
Alright, coming back to this thread after a couple months.
Problems still persist - I've swapped the front door weather sealing (both doorside and body side), and the main rear hatch stripping. No change. Next parts sale I'll grab the rear door seals and the seal that goes between the rear hatch and tailgate.
I pride myself on critical thinking and tough troubleshooting skills - but I just can't find a correlation here.
Some days it's 'OK', some days it's awful. Often time it's almost 'ok' in the morning, and bad on the drive home from work. Outside temperature seems like maybe the only strong correlations that I can find, but I don't know what would cause that.
One thing that I need help from the community on (and please, don't go off memory here - do me a favor and test this out!).
When I discovered this, I had the thought that maybe the engine intake was somehow creating a vacuum in the cabin. I pulled the fender well liner off and drove around like that for a while, no change to the ear pain & no change to the noise coming from between the headliner and roof when the sunshade is opened. I don't know what would cause this noise, but since I've been grasping at straws for over a year now I'd just like to know if this is something that everyone's vehicle does.
I did have the injectors cleaned/checked by FIS in CO (I had 'DIY' cleaned them at home when I built the engine, and the report from FIS actually came back really good before they even did any cleaning, so that was nice to see I guess). I'm also going to swap the fuel pump because I've had a couple long cranks. No sort of weird fuel trims though, so I don't think it's affecting engine performance.
Right now the plan is to take this to the Car Care Nut (~4 hour drive) from me sometime this winter. I hate that idea - I've done the hard diagnostic thinking. I've gone through all the information that I can find. I've resorted to the parts cannon at this point, but something is still wrong & at this point it's going to take someone with more experience than I have to find & correct it.
(especially before I yank the TRD supercharger off 2UZ 4runner I bought for $1800 and drop it on the LX, hah).
Problems still persist - I've swapped the front door weather sealing (both doorside and body side), and the main rear hatch stripping. No change. Next parts sale I'll grab the rear door seals and the seal that goes between the rear hatch and tailgate.
I pride myself on critical thinking and tough troubleshooting skills - but I just can't find a correlation here.
Some days it's 'OK', some days it's awful. Often time it's almost 'ok' in the morning, and bad on the drive home from work. Outside temperature seems like maybe the only strong correlations that I can find, but I don't know what would cause that.
One thing that I need help from the community on (and please, don't go off memory here - do me a favor and test this out!).
- Open your sunroof shade (but leave the sunroof closed)
- Get up to 30-40 mph
- Punch the gas
- Listen
When I discovered this, I had the thought that maybe the engine intake was somehow creating a vacuum in the cabin. I pulled the fender well liner off and drove around like that for a while, no change to the ear pain & no change to the noise coming from between the headliner and roof when the sunshade is opened. I don't know what would cause this noise, but since I've been grasping at straws for over a year now I'd just like to know if this is something that everyone's vehicle does.
I did have the injectors cleaned/checked by FIS in CO (I had 'DIY' cleaned them at home when I built the engine, and the report from FIS actually came back really good before they even did any cleaning, so that was nice to see I guess). I'm also going to swap the fuel pump because I've had a couple long cranks. No sort of weird fuel trims though, so I don't think it's affecting engine performance.
Right now the plan is to take this to the Car Care Nut (~4 hour drive) from me sometime this winter. I hate that idea - I've done the hard diagnostic thinking. I've gone through all the information that I can find. I've resorted to the parts cannon at this point, but something is still wrong & at this point it's going to take someone with more experience than I have to find & correct it.
(especially before I yank the TRD supercharger off 2UZ 4runner I bought for $1800 and drop it on the LX, hah).
I haven't read through this entire thread, but have you had somebody "tape" you in, as in tape every door jam, body line, and window up? I'm thinking, based on the last 60 seconds of read time, that it could be a air flow disturbance and potentially multiple things creating this (perfect combo of old seals, a gap, misaligned door stiker, hood, etc)
I would even tape the rear air outlets on the D Pillar, and potentially the HVAC Intake right by the windshield. If it goes away, remove one section of tape at a time until it comes back. If you think it's a pressure issue
I would even tape the rear air outlets on the D Pillar, and potentially the HVAC Intake right by the windshield. If it goes away, remove one section of tape at a time until it comes back. If you think it's a pressure issue
I really respect the effort you have put into this problem. The "taping in" is an interesting idea. Why not? Cheap test. Also, I go back to early in this thread when I mentioned body panels loose on Sprinter Vans causing droning at highway speed. Another cheap idea would be to get a fairly large magnet(s) placed in a sock and randomly placed around your Cruiser to add weight to eliminate possible body panel buffering. Just another possible idea. Really appreciate your tenacity here!
Also, I never replied to you about the nice camera mount you made for me. Thanks!
- Thread starter
- #274
Coming back to this - it's still a problem, but I've now confirmed that it's (mostly) worse when the temp outside is above 40F. I thought that placebo the first winter I had it (as it seemed to get better over the winter), but it did it this past winter too.
At this point? It's gotta be transmission or engine.
As a refresher, the engine in this truck is a 2UZ out of a tech school closet that I bought & built from the bare block up by the book - totally possible that I bodged something there, but, I'd also sorta expect it to have dissembled itself by now if that was the case. The fact that it's also not dependent on engine speed (can shift gears and it doesn't really change) also makes me thing that the engine is OK. I just changed the oil again (about the 15K mark since I built it), but I grabbed an oil sample this time so I'll send that off to see if there's any apparent issues there.
That leaves the transmission. When I swapped engines, I noticed this trans (at the very least) has an aftermarket torque converter. I have no idea what else was done/was not done to this or what happened to the original TC - but that makes me suspicious.
Now, obviously LC/LX trans aren't super common, and it's a non-trivial amount of work to just go swapping on a whim, so I've been trying to do some other things to understand the problem... it's just challenging when the vibrations are so low frequency that they show up as changes in ear pressure, haha. I'm also surprised that if the trans is vibrating like this that it also hasn't dissembled itself...
But, the fact that the transmission doesn't have a thermostat (and therefor depends on outside temps) sorta lines up with the whole 'it gets worse when it gets warm outside'. On the other hand, when I do start with a very cold transmission (sub 40F-ish), I sorta feel like the truck seems like it's tripping over it's own feet (I don't really know how to describe it, but that's the best I can do) until the trans warms up a bit. Not a super obvious thing because it gradually gets better, but that's also an oddity. And it's not the engine that's coming up to temp - that happens way faster than the trans, and it'll still feel clumsy once the engine is at temp before the trans gets up above 90-100F.
Also as a reminder, since this started (well, I bought this truck non-running with a blown engine, so really this is all the things I've done to the truck - no idea when the problem actually started)...
So... Transmission next I think? I've got a TRD supercharger sitting in the garage as a treat for the 'ol gal once she starts behaving...
At this point? It's gotta be transmission or engine.
As a refresher, the engine in this truck is a 2UZ out of a tech school closet that I bought & built from the bare block up by the book - totally possible that I bodged something there, but, I'd also sorta expect it to have dissembled itself by now if that was the case. The fact that it's also not dependent on engine speed (can shift gears and it doesn't really change) also makes me thing that the engine is OK. I just changed the oil again (about the 15K mark since I built it), but I grabbed an oil sample this time so I'll send that off to see if there's any apparent issues there.
That leaves the transmission. When I swapped engines, I noticed this trans (at the very least) has an aftermarket torque converter. I have no idea what else was done/was not done to this or what happened to the original TC - but that makes me suspicious.
Now, obviously LC/LX trans aren't super common, and it's a non-trivial amount of work to just go swapping on a whim, so I've been trying to do some other things to understand the problem... it's just challenging when the vibrations are so low frequency that they show up as changes in ear pressure, haha. I'm also surprised that if the trans is vibrating like this that it also hasn't dissembled itself...
But, the fact that the transmission doesn't have a thermostat (and therefor depends on outside temps) sorta lines up with the whole 'it gets worse when it gets warm outside'. On the other hand, when I do start with a very cold transmission (sub 40F-ish), I sorta feel like the truck seems like it's tripping over it's own feet (I don't really know how to describe it, but that's the best I can do) until the trans warms up a bit. Not a super obvious thing because it gradually gets better, but that's also an oddity. And it's not the engine that's coming up to temp - that happens way faster than the trans, and it'll still feel clumsy once the engine is at temp before the trans gets up above 90-100F.
Also as a reminder, since this started (well, I bought this truck non-running with a blown engine, so really this is all the things I've done to the truck - no idea when the problem actually started)...
- Every bushing on this truck was changed. Including upper/lower AHC shock bushings, and body mounts.
- Replaced AHC accumulators & flushed fluids.
- All new wheel bearings
- New ball joints
- Rebuilt steering rack (rebuilt here in my garage - still holding fine!
- Installed panel deadening (dynamat knock-off) on floor/ceiling/doors/etc
- Doug Thorely short tube headers
- New wheels/tires
- Tried 4 different OEM Toyota rear drive shafts (seems like I'm good at finding boulders with them... Hah!) , replaced front drive shaft.
- Front/Rear diffs have been rebuilt, re-geared and ARB lockers installed.
- Replaced main muffler
- Installed sliders & rear swing-out bumper.
- Reglued both the hood sheet metal & the roof sheet metal to the supporting braces.
- Transfer case has been swapped.
- Door seals have been replaced.
- Windshield has been replaced.
- I've taped up every nook, cranny, etc, that I could find to make sure it wasn't a weird air infiltration thing.
- Adjusted tailgate stoppers.
- Probably a lot more that I'm forgetting at this point.
So... Transmission next I think? I've got a TRD supercharger sitting in the garage as a treat for the 'ol gal once she starts behaving...
Last edited:
FamilyCamper
SILVER Star
Short answer but thanks for posting up all the updates. I think you've put so much into that truck at this point get a cheap used trans and swap it. aftermarket torq converter sounds sketchy for sure. One step at a time but you want to be able to enjoy driving it after all that work and hopefully the trans would solve it
Have you tried adding weight to the exhaust system?
It is one of the band aids that Toyota came up with to "solve" vibrations in the LC on one of their TSBs, together with the frame weight..
It is one of the band aids that Toyota came up with to "solve" vibrations in the LC on one of their TSBs, together with the frame weight..
This is the first I've ever heard or seen of this!
They came up with this one attached to this thread:
It's for cabin drone while on D and stationary, but considering the length of part replacements @LJE went through, and the fact that he's considering a transmission swap i think a $20 part is worth trying.
They have different ones based on the frequency of the vibration, impossible to measure w/o specialized equipment, but I'd go for the heaviest first
17581–70090 Same Damper, Exhaust Pipe (32 Hz)
17581–50090 Same Damper, Exhaust Pipe (39 Hz)
17581–17020 Same Damper, Exhaust Pipe (48 Hz)
17581–50140 Same Damper, Exhaust Pipe (43.8 Hz)
17581–70080 Same Damper, Exhaust Pipe (34.6 Hz)
The wife's RX350 went through this TSB (or something similar) when it was newer.. I didn't feel a difference but I barely drove that car.
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- #279
That TSB is really only applicable at idle - and 40hz is way higher frequency than what's going on now (best I can measure, it's in the sub 6-hz range).They came up with this one attached to this thread:
It's for cabin drone while on D and stationary, but considering the length of part replacements @LJE went through, and the fact that he's considering a transmission swap i think a $20 part is worth trying.
They have different ones based on the frequency of the vibration, impossible to measure w/o specialized equipment, but I'd go for the heaviest first
17581–70090 Same Damper, Exhaust Pipe (32 Hz)
17581–50090 Same Damper, Exhaust Pipe (39 Hz)
17581–17020 Same Damper, Exhaust Pipe (48 Hz)
17581–50140 Same Damper, Exhaust Pipe (43.8 Hz)
17581–70080 Same Damper, Exhaust Pipe (34.6 Hz)
View attachment 4134814
The wife's RX350 went through this TSB (or something similar) when it was newer.. I didn't feel a difference but I barely drove that car.
(much) earlier on I did have the 40hz resonance due to a bad driveshaft & bad rear output bearing on the transfer case, and there is some exhaust resonance at idle in D still - but, again, very different sound/sensation than the main issue I'm tracking down here unfortunately.
My muffler also already has a weight - unsure of which one it is though.