trouble shooting help or ideas???

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M

Mxndrnks

10 Year 15 Year
Joined
Nov 12, 2006
Threads
29
Messages
1,608
Location
Bird Rock, CA
I need some help trouble shooting a problem. Last May after towing a fully loaded 12ft enclosed Uhaul with the truck loaded down as well from San Francisco to San Diego I started getting a noise when I would pull up to a stop light. The noise was best described as a rotational grinding/whining noise. The noise would only appear every now and then and not consistently. When the noise would start, if I shifted from Drive to Neutral, it would immediately go away. Shift back to drive and it would start up again until I started to drive away. It only happened when stopped at red lights and stop signs with the truck in gear. Based on threads here and another I posted about transmission problems, I got the feeling it may be the torque converter.

I have driven the truck very little since the noise started last May. Fast forward to now. The noise is no longer there. But when in drive at red lights, stop signs, etc. with the truck in gear I get a low rumble/vibration. Shift to neutral/park and it goes away. In neutral/park the rpm's sit around 750. In gear and stopped the RPM's start at around 750 and then drop to about 600 and the low noise rumble starts.

I took it to a highly recommended toyota guy here in San Diego (SD Trux not a dealer) to have him look at it and do a 60K service on it since it was close to 150K now any way. He can reproduce the issue. But in his opinion the TC and transmission are working perfectly. I can partially agree with this as the transmission has always seemed buttery smooth. When he changed the fluids he said it looked perfect as well. No metal, burned smells, etc. He thinks it is something with the modifications on the truck. He thinks the frequency hum/vibration that I am hearing is coming from the Skid plates, suspension, bumpers, something in the mods..... But, basically he doesnt think it is a engine or transmission problem.

Now, had this noise always been just a hum/vibration I might buy into that. But, it started as a rotational grinding noise first. Not only that, I have completely rebuilt the entire suspension since the noise started. I have run around in the truck with out the Skids and the noise is still there. You also only here it inside the truck. Not outside, and nothing in the engine compartment. He did suggest it could be two different issues. Which is a possibility.

The history of MODS:

3 years ago I installed a Slee 2.5" Medium lift and Slee step sliders.
2 years ago I added an 03+ arb and superwinch Ep9
April of this year I added a BOIR rear bumper and Skids
May of this year after towing noise started
August of this year I:
Replaced all sway bar bushings front and rear
replaced the rear UCA's
Installed rear Slee heavy duty LCA's
Changed out rear Springs to 863's
Installed Radflo 2.5 remotes front and rear
Installed Total Chaos UCA's in front
Installed Timbren's front and rear
Installed new sway bar links front and rear
replaced the front diff support that was shown in the 200k refresh thread.
And completely refreshed everything on the underside with new paint and replaced all bolts that were rusted.

So suspension wise, everything is brand new on the underside of the truck. Hell it looks like it just rolled off the show room floor.

So, if I cant find it and the mechanic cant find it..... where would you start? Engine mounts? body mounts? Ideas? Any one had a similar issue?

My biggest fear is to write this off as a harmonic vibration issue and then get way out there and be stranded.

Thanks and sorry for the long post.... just trying to get as much info out as I can....
 
Well, I can't reply with as much information. But I have a very similar issue. At the stoplights the entire truck rumbles ( low freuqency vibration) and sounds like a 12" sub woofer going off. I can either push the gas pedal lightly to raise RPM's or shift to N. it's pretty damn annoying, I'm wondering if adjusting the idle RPM can cure this. It's almost embarrassing when you take friends out and your entire truck sounds like it is storing energy and about to explode. As for how long I have has this issue, probably 2.5years, no trans issues.
 
That is great that you have had it go that long with no issues... But, yeah it does sound as if something is eventually going to explode.

You know I do remember a tech bulletin about exhaust boom and a fix.... I wonder if I can find it again and if that may be the issue?????

Can you hear your outside the truck or only inside? I wonder if I should put the flux capacitor back on????LOL!
 
There was a TSB about booming. I can't hear it outside of my truck FYI. It may be the issue, a bad exhaust hanger coming in contact with the exhaust pipe transmitting the boom into the cab. Who knows, my truck has so many rattles and booms I could be driving next to a dump truck and not know it haha. Maybe the flux capacitor needs to go back on. Mine is a paper weight at work, or a projectile if somebody does something stupid. Which is common :)
 
I haven't found one yet. But, I am definitely starting to think it is a Harmonic thing like the shop said. I also did a 60K service on it and it is running better. The RPM's don't drop as low as often... therefore it isnt happening as often. I am going to do the throttle body cleaning and possibly seafoam treatment and see what that does. Next after that I will be looking into adjustments to Idle......
 
Mxndrnks said:
I haven't found one yet. But, I am definitely starting to think it is a Harmonic thing like the shop said. I also did a 60K service on it and it is running better. The RPM's don't drop as low as often... therefore it isnt happening as often. I am going to do the throttle body cleaning and possibly seafoam treatment and see what that does. Next after that I will be looking into adjustments to Idle......
Click to expand...

Let me know what seafood does. I would be thrilled to get rid of it. Is there a way to adjust the idle speed? Another 150RPM and she would be good.
 
Seafood?????:confused:

j/K

If I do it and it does anything i will be sure to post. I haven't looked into the trying to adjust Idle yet. So, I have no idea if it can be done or is easy to do. But, yeah... I only need like 50-150 rpms and the issue is gone. It actually goes away when I let off the break.... So only a small adjustment...
 
Mxndrnks said:
Seafood?????:confused:

j/K

If I do it and it does anything i will be sure to post. I haven't looked into the trying to adjust Idle yet. So, I have no idea if it can be done or is easy to do. But, yeah... I only need like 50-150 rpms and the issue is gone. It actually goes away when I let off the break.... So only a small adjustment...
Click to expand...

haha. I think there is a way to up the idle speed just a tad. I'll check the FSM when I get home from work. Does anybody know if there is a idle adjuster before I look for 30 minutes? I'm sitting in traffic with my truck rumbling and booming. my idle is right at 600RPM. If I go to 650-700 it's silent and smooth.
 
Mine does this moderately when the A/C kicks on, which seems to be fairly often as it runs just to dehumidify when it's cool out. Try turning off the A/C and see if it goes away. I leave mine on because the wife drives the 100 most, and might not realize why her windows are fogging on a cold day. But I certainly notice when it kicks on by the rumbling, and the rumbling goes away when I turn off the A/C. It's not bad on my '03, but I listen for things like that.
 
Does the cruiser have active engine/transmission mounts? Even if it didn't, I'd definitely consider replacing the engine/tranny mounts especially on a high mileage car. Just like suspension bushings, the engine/tranny mounts can be way out of spec yet still be functional, but invite issues such as these. It shouldn't cost too much to replace them so it's worth a shot.

For a low rpm issue like this, it could also be a worn harmonic balancer at the nose of the crank driving the accessories. It could invite funny resonances in the rotational assembly if out of spec.
 
Back on this topic....

After I did a 60K service the vibrations got a lot better. But were still there just less noticeable.

After running around in the desert two weeks ago, the original rotational grind/whine is back. It is definitely on the front of the engine. It does not sound like when a belt is loose, but more of a grind/worn bearing issue. It only happens when the car is IN gear (not when in park or neutral). Any tips or ideas for trouble shooting the part that seems to be failing?
 
I would like to solve my "booming" as well. I would LOVE to adjust my idle RPM up 50 revs. That would be awesome. Does anybody know if there is a adjuster anywhere on the 100? trying to push the gas and brake at the same time is getting old, and constantly going D>N>D at stop lights seems like a lot of added wear.
 
I have the same problem. It happens intermittently in gear when stopped.
 
Mine does it intermittently as well. I've identified that it happens when that ac compressor comes on when stopped in drive. At least I think it's the ac compressor
IMG_0261.jpg
 
petrotk40 said:
Mine does it intermittently as well. I've identified that it happens when that ac compressor comes on when stopped in drive. At least I think it's the ac compressor
Click to expand...

I did some solo test the other day and there is definitely a correlation between the noise and the AC. I am REALLY hoping it is somehting beside the AC though. I just replaced my AC compressor a couple of years ago.....
 
I think that when the AC compressor clutch engages, the RPM's are raised ever so slightly to where it resonates somewhere. I need to slap some big hose clamps on the cats and see what happens.
 
my 4runner has a spring loaded adjuster on the a/c idle up valve that lets you adjust the idle speed when the compressor engages. maybe the 100 has a similar feature. i actually tapped into the switch(on the runner) to engage the idle up when my arb air compressor turns on to increase the rpms when filling tires. i recently added my winch to the mix as well.

back on subject why don't you reinstall the "flux capacitor" to see if the noise is still there? is it not possible with the sliders installed? I know there has been talk of this before but there has to be a reason that part is on the truck. toyota obviously added that after the truck was designed and built because they found some sort of harmonic problem with it. that thing is a band aid for something.

someone should also remove their sliders altogether and drive around a while to see if there is any difference. i noticed in the original post this started right after rear bumper and sliders installed. all of these heavy accesories could cause some sort of harmonic imbalance. plastic and foam(stock bumpers) absorb noises/vibrations, metal could amplify it. Does everyone that is having this problem have aftermarket bumpers and/or sliders?
 
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There was a TSB on the booming....mine does it a little at idle in D but I also have it between 1800-2000 rpms when driving and then disappears....figure it is just harmonics as I have replaced both front axles...new gears in front and rear diffs....etc.

I am going to replace my exhaust from CAT back and put new pipe and a Magnaflow muffler this year and change the bends in pipe for more clearance especially towards rear where spare used to be....but hoping that fixes it.

Only other rumble i have is slowing for lights when I get around 5mph or before complete stop I can hear and feel every single cleat in my tire tread pattern. LOL
 
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