Whistling noise at low RPM and under load (1 Viewer)

[fjobsessor]

For the last couple of years on my 1985 FJ60 (142K miles), I've had an intermittent whistling noise that seems to happen at low RPM and under load. It happens in mostly second and third gears. I haven't noticed it in fourth or reverse. The noise seems to be coming from the front or under the vehicle and doesn't seem to speed up or slow down at faster speed. It's just a constant noise that only occurs when I'm moving in gear and goes away if I let off the gas (not under load). It runs great but it does buck a bit when accelerating at low speeds.

Here are some things I've done after the noise started that seem to have no impact:

• Greased the drive train.
• New brake pads up front.

Here are some things that were done in the last few years but before the noise showed up (all done by a professional shop):

• Removed and resurfaced intake/exhaust manifolds. replaced all vacuum hoses, new gaskets insulator plate.
• Clutch, pressure plate, throw-out bearing. Crankshaft seal-rear, front transmission seal and service fluid. Clutch master and slave cylinder and flush system.
• Replaced water pump.
• New belts.
• Front axle rebuild, steering box rebuild, EGR valve cooler gasket, drain/fill transfer case and front differential, replace exhaust hangers, new carb. cooling fan wiring and wrap, flush and fill clutch and brake hydraulic fluids, adjusted parking brake, repaired broken hub bolt.

I suspect it's related to the vacuum hoses and/or manifold work. Could also be the drivetrain but seems premature for a cruiser that only has 142K miles.

Is there a common issue that would make this noise under these conditions?

Any guidance on what to check or how to troubleshoot further would be greatly appreciated.

 

[HemiAlex]

See if it stops when the ac is off.

My expansion valve makes a similar noise.

 

[fjobsessor]

See if it stops when the ac is off.

My expansion valve makes a similar noise.

Thanks for the suggestion. My A/C is never on.

 

[dbbowen]

Its could be your idler shaft in the tcase. If it is, its gear noise from it being slightly not perfectly straight under the light load and the idler gears whining. If you have a 2f still check for wear. When was your last tcase rebuild? Does the noise go away when you lift your foot off of the pedal? can you feel the noise or vibratiuons if you hold the tcase shifter? A worn idler shaft will misalign the idler gears enough to make it whine. It sounds like a high pitched supercharger almost hah and mostly happens in light load cruising situations like maintaining 65 mph and what not. If its like a whistle though its probably a vacuum leak or a vsv installed backwards

 

[GRpufnstuf]

shoot starting fluid at vacuum areas that may be suspect. The revs should climb if there is a leak. DON'T set yourself on fire please

 

[fjobsessor]

Its could be your idler shaft in the tcase. If it is, its gear noise from it being slightly not perfectly straight under the light load and the idler gears whining. If you have a 2f still check for wear. When was your last tcase rebuild? Does the noise go away when you lift your foot off of the pedal? can you feel the noise or vibratiuons if you hold the tcase shifter? A worn idler shaft will misalign the idler gears enough to make it whine. It sounds like a high pitched supercharger almost hah and mostly happens in light load cruising situations like maintaining 65 mph and what not. If its like a whistle though its probably a vacuum leak or a vsv installed backwards

The transfer case has never been rebuilt to my knowledge. The noise does go away when I lift my foot off the pedal. I haven't tried feeling for vibrations on the shifter but I'll give that a shot next time I'm driving. I'm inclined to agree with your assessment about it being the idler shaft/gears because it sounds like a high-pitched supercharger.

I drove it yesterday and confirmed it does happen in fourth gear too but just not as often.

I had eventually planned on having a shop replace the 4-speed with the HF55 and rebuilding the transfer case but I'm unemployed at the moment so now I'm wondering if I can rebuild the transfer case on my own. Can anyone recommend a kit?

 

[fjobsessor]

shoot starting fluid at vacuum areas that may be suspect. The revs should climb if there is a leak. DON'T set yourself on fire please

Since all the vacuum lines and gaskets were just gone through a couple of years ago and the noise only happens when driving I'm inclined to think it's something in the drive train as @dbbowen suggested.

I don't put a lot of miles on her. I've only put on around 10K miles in the 5 years since I've owned the rig.

 

[dbbowen]

The transfer case has never been rebuilt to my knowledge. The noise does go away when I lift my foot off the pedal. I haven't tried feeling for vibrations on the shifter but I'll give that a shot next time I'm driving. I'm inclined to agree with your assessment about it being the idler shaft/gears because it sounds like a high-pitched supercharger.

I drove it yesterday and confirmed it does happen in fourth gear too but just not as often.

I had eventually planned on having a shop replace the 4-speed with the HF55 and rebuilding the transfer case but I'm unemployed at the moment so now I'm wondering if I can rebuild the transfer case on my own. Can anyone recommend a kit?

Cruiser outfitters (@cruiseroutfit ) or Valley hybrids (@orangefj45) here both sell great kits and it is very much so a DIY job if you are inclined.

If i was you id still spray starter fluid over all of the vacuum hoses in your engine bay to look for leaks first, its a really cheap and easy option. Also check both of your diffs to be sure the gear oil is good and your front hubs are unlocked. As well as your trans fluid level and maybe drain the trans fluid and add some Redline MT90 to the trans first if you dont have the time to pull the case


The Tcase rebuild can be done without dropping the trans under the truck its just kind of a pain. Heres a few videos on how to do it:









For me, My truck just whines, i tried rebuilding twice, I tried a brand new transfer case, everything. I have a really s***ty transmission adapter to mate the t case to a gm trans and i think the adapter is causing the misalignment. ITs definitely the idler shaft though because you can see the wear on it when you take it out.

 

[fjobsessor]

Cruiser outfitters (@cruiseroutfit ) or Valley hybrids (@orangefj45) here both sell great kits and it is very much so a DIY job if you are inclined.

If i was you id still spray starter fluid over all of the vacuum hoses in your engine bay to look for leaks first, its a really cheap and easy option. Also check both of your diffs to be sure the gear oil is good and your front hubs are unlocked. As well as your trans fluid level and maybe add some Redline MT90 to the trans first if you dont have teh time to pull the case


The Tcase rebuild can be done without dropping the trans under the truck its just kind of a pain. Heres a few videos on how to do it:









For me, My truck just whines, i tried rebuilding twice, I tried a brand new transfer case, everything. I have a transmission adapter to mate the t case to a gm trans and i think the adapter is causing the misalignment. ITs definitely the idler shaft though because you can see the wear on it when you take it out.

Thanks a bunch for the suggestions and guidance. Very helpful.

I'll try spraying the vacuum hoses and if nothing comes of that I might go ahead and do the rebuild. I've already watched the videos you suggested to get an idea of the effort. I hadn't considered doing the rebuild while keeping the transfer case in the rig but something to think about. All I have is jack stands and a floor jack.

In any case, thanks again!

 

[dbbowen]

Thanks a bunch for the suggestions and guidance. Very helpful.

I'll try spraying the vacuum hoses and if nothing comes of that I might go ahead and do the rebuild. I've already watched the videos you suggested to get an idea of the effort. I hadn't considered doing the rebuild while keeping the transfer case in the rig but something to think about. All I have is jack stands and a floor jack.

In any case, thanks again!

Dude no problem. Ive done the rebuild and replace while it was in the vehicle like 4 times. put the truck up as high as you can on floor jacks to get you some room under there, then undo the crossmember and lower the transfer case as much as you can (the motor mounts will flex) with the jack under the trans. Then put a jack stand or a bunch of wood or something under the trans to support the trans so youre not just relying on the jack. That should be all you need to do it under the truck

 

[cps432]

I second the T-case opinion. I had a whine that turned into a chatter and eventually a physical vibration. After rebuilding both axles, replacing the 4 speed with a 5 speed, rebuilding the sad T-case, and installing new suspension and tires my truck is still obnoxiously loud. But that whine is gone. It doesn’t sound like an airport/rollercoaster under my arse anymore. Just the classic roar of the 2F and H55F.

 

[fjobsessor]

I have updates. It turns out I'm able to reproduce the same whistling sound while the rig is parked and cranking the RPM up to about 2K. I'm not sure why I didn't try this before. I guess I assumed if it was a vacuum leak it would always be audible even during idle. Now I'm convinced it's a vacuum leak which makes sense because I'm pretty sure this showed up right after I got it back from my shop after they "Removed and resurfaced intake/exhaust manifolds. replaced all vacuum hoses, new gaskets insulator plate."

I already spent some time a little while ago chasing down the leak but I haven't found it yet.

Here's a quick video with the noise:

 

[dbbowen]

I have updates. It turns out I'm able to reproduce the same whistling sound while the rig is parked and cranking the RPM up to about 2K. I'm not sure why I didn't try this before. I guess I assumed if it was a vacuum leak it would always be audible even during idle. Now I'm convinced it's a vacuum leak which makes sense because I'm pretty sure this showed up right after I got it back from my shop after they "Removed and resurfaced intake/exhaust manifolds. replaced all vacuum hoses, new gaskets insulator plate."

I already spent some time a little while ago chasing down the leak but I haven't found it yet.

Here's a quick video with the noise:

thats a hell of a lot easier than a tcase rebuild lol

 

[fjobsessor]

thats a hell of a lot easier than a tcase rebuild lol

More updates. I hooked up a smoke machine looking for a vacuum leak and just found the rubber boot on the top of the carb was toast. After replacing that, no leaks other than some slight leaks coming from EGR modulator valve and the top of the EGR pipe. I'm guessing that neither of these are my issue.

So back to square one. What else could be making the whistling noise? Again, it seems to make a noise either at lower RPM under load or at higher RPM with no load.

 

[OSS]

Carefully check every connection in the PCV plumbing

 

[fjobsessor]

Carefully check every connection in the PCV plumbing

Did that today. Even removed the hoses and smoke tested them off the rig.

 

[Alex7]

Did that today. Even removed the hoses and smoke tested them off the rig.

Hello, I think I may be getting the same noise. I didn't/havent tried it idle, but I did notice it under throttle/driving the other day. Any updates with yours ? Thank you.

 

[fjobsessor]

Hello, I think I may be getting the same noise. I didn't/havent tried it idle, but I did notice it under throttle/driving the other day. Any updates with yours ? Thank you.

No real progress. I initially thought it just happened while under load and driving but I can consistently reproduce the noise just by operating the throttle while it's stationary. While I'm driving there's definitely a hesitation issue but not sure if that's related.

At this point I suspect it may be EGR related but no evidence to back that up yet. My rig only has 142K miles but most of the EGR stuff is pretty rusty.

 

[OSS]

EGR system is inactive at idle. Install a little vacuum tee in the vacuum hose leading to the EGR valve and a vacuum gauge to the tee. You can then see when it actuates.