twanging noise on steep hill start

[tucktuck8]

I was parked faced uphill on a steep driveway and I put it into drive and rolled back a little (maybe 3 feet) then hit the accelerator and it went forward but made a very weird twanging/clunking noise then stopped once i got moving a little bit. I then put it into 4lo and did the same hill start and it didn't roll back or make the clanking noise.

any Ideas to what this could be?

 

[netwon]

It is your hill start assist. Prevents excessive roll back for a couple of seconds.

 

[philskeeter]

I was parked faced uphill on a steep driveway and I put it into drive and rolled back a little (maybe 3 feet) then hit the accelerator and it went forward but made a very weird twanging/clunking noise then stopped once i got moving a little bit. I then put it into 4lo and did the same hill start and it didn't roll back or make the clanking noise.

any Ideas to what this could be?

had the same thing happen to me two nights ago. When I gave it gas while it was slowly rolling back it jerked hard and would lose traction and the traction light would blink and beep. It was dry and I accelerated slowly. To not to it I hold the brake and barely give it gas so that when I let off of the brake it won't roll back then when I give it more gas it takes off. This is what I do when pulling the boat out of the water.

 

[tucktuck8]

If it's supposed to be a hill start assist then this is not the case. When I let off the brake it IMMEDIATELY starts to roll back. Then while I'm rolling back I press on the accelerator and it starts making the twaning/pinging noise rapidly (pretty loudly) from the front until it gets going forward then it stops. I notice that it makes the same noise while I'm using the DAC (Downhill Assist Control). I was in 4lo and had the diff locker on while dissenting a hill about 5-8mph (dirt) and when i pushed the DAC it would just shudder the brakes and make the same noise. It was like ABS was coming on but it would make an awful noise and pulse in the same manner as the hill start assist would.

I just got my runner and I don't want to have a costly experiences with it already. I've already been through expensive repairs with my Subaru WRX and I just want reliability, that's why I bought my 4runner. I love the car and it runs perfect except for this. I'm pretty mechanically inclined so if you have advice on how to fix it without going to the dealer that would be a great help.

 

[JB.]

I'm pretty mechanically inclined so if you have advice on how to fix it without going to the dealer that would be a great help.

The only required fix is in your viewpoint. I've read nothing here that would make me think either one (hill start assist or downhill assist) is working abnormally.

 

[6wheelin]

Reviving this thread. Did the OP figure this out? I'd be curious what the solution is? As it just happened to me in my '05 runner. It did it on a hill I've been on before and the the hill assist worked great, prevented the truck from rolling back. The only thing that has changed, I had rock sliders welded on the frame. Is there any electrical wiring that may have been heated up and disabled the hill assist?

Thanks for any replies.

 

[keakar]

If it's supposed to be a hill start assist then this is not the case. When I let off the brake it IMMEDIATELY starts to roll back. Then while I'm rolling back I press on the accelerator and it starts making the twaning/pinging noise rapidly (pretty loudly) from the front until it gets going forward then it stops. I notice that it makes the same noise while I'm using the DAC (Downhill Assist Control). I was in 4lo and had the diff locker on while dissenting a hill about 5-8mph (dirt) and when i pushed the DAC it would just shudder the brakes and make the same noise. It was like ABS was coming on but it would make an awful noise and pulse in the same manner as the hill start assist would.

I just got my runner and I don't want to have a costly experiences with it already. I've already been through expensive repairs with my Subaru WRX and I just want reliability, that's why I bought my 4runner. I love the car and it runs perfect except for this. I'm pretty mechanically inclined so if you have advice on how to fix it without going to the dealer that would be a great help.

that "is" how it works, its not there to apply the brake for you, its there to prevent tranny damage or something but it make some funny noises if you give it gas as it starts rolling backwards.

Reviving this thread. Did the OP figure this out? I'd be curious what the solution is? As it just happened to me in my '05 runner. It did it on a hill I've been on before and the the hill assist worked great, prevented the truck from rolling back. The only thing that has changed, I had rock sliders welded on the frame. Is there any electrical wiring that may have been heated up and disabled the hill assist?

Thanks for any replies.

its normal, just ignore it and use the brake rather then accelerator to stop the backwards roll "before" giving it gas

 

[6wheelin]

that "is" how it works, its not there to apply the brake for you, its there to prevent tranny damage or something but it make some funny noises if you give it gas as it starts rolling backwards.




its normal, just ignore it and use the brake rather then accelerator to stop the backwards roll "before" giving it gas

I did apply the brakes then accelerate up the steep grade and of course it works. But it's annoying that a hill start assist should work so poorly. My 2017 Honda Civic HA works flawlessly. Thanks for the reply.

 

[Prommy]

I did apply the brakes then accelerate up the steep grade and of course it works. But it's annoying that a hill start assist should work so poorly. My 2017 Honda Civic HA works flawlessly. Thanks for the reply.

The grades a 3k lbs civic is designed to handle and what the 4k+ lbs 4Runner is designed to handle makes me question the validity of comparing the two.

 

[6wheelin]

that "is" how it works, its not there to apply the brake for you, its there to prevent tranny damage or something but it make some funny noises if you give it gas as it starts rolling backwards.




its normal, just ignore it and use the brake rather then accelerator to stop the backwards roll "before" giving it gas

The grades a 3k lbs civic is designed to handle and what the 4k+ lbs 4Runner is designed to handle makes me question the validity of comparing the two.

I personally think it's a valid comparison. One works the other is wonky. What does it matter 4k lbs or 3k lbs? The tech should work,

 

[Prommy]

I personally think it's a valid comparison. One works the other is wonky. What does it matter 4k lbs or 3k lbs? The tech should work,

It is working as designed.

 

[6wheelin]

It is working as designed.

Yeah that video in no way represents how HAC works with my vehicle. When I was on a pretty typical hill where I live, light turned green and i moved my foot from the brake to the accelerator and the 4runner rolled back and made the twanging noise and the brakes shuddered. It was as though the entire engine was immobilized I could not move forward. I had people behind me. Finally the runner moved. It was a disconcerting feel to say the least.

Later my wife and I found another steep hill but less crowded and replicated the same conditions. From a complete stop I rapidly moved my foot from the brake pedal to the accelerator and the runner literally sounded like it was tearing itself apart, the vehicle refused to move forward it just continued to make the twanging noise. The only way I could get the truck to move up the hill was to keep my left foot on the brake and apply my right foot to the accelerator.

Does that sound like a properly functioning hill assist? Feels more like a anti-climb desist.

 

[dasx86]

Yeah that video in no way represents how HAC works with my vehicle. When I was on a pretty typical hill where I live, light turned green and i moved my foot from the brake to the accelerator and the 4runner rolled back and made the twanging noise and the brakes shuddered. It was as though the entire engine was immobilized I could not move forward. I had people behind me. Finally the runner moved. It was a disconcerting feel to say the least.

Later my wife and I found another steep hill but less crowded and replicated the same conditions. From a complete stop I rapidly moved my foot from the brake pedal to the accelerator and the runner literally sounded like it was tearing itself apart, the vehicle refused to move forward it just continued to make the twanging noise. The only way I could get the truck to move up the hill was to keep my left foot on the brake and apply my right foot to the accelerator.

Does that sound like a properly functioning hill assist? Feels more like a anti-climb desist.

if the "twanging" noise you're talking about is a rapid clicking coming from the dash, at about the height of the steering wheel, but to the left of the steering wheel.... I think this is traction control kicking in. would cause the throttle to cut out as well.

I've had this happen as well, which is why I'm interested in doing this mod:
http://www.toyota-4runner.org/engin...8882-new-fine-grained-vsc-off-mod-v6-1gr.html

my traction control seems to be way too sensitive on steep inclines.

edit: lock your center diff and see if it you can replicate the issue. locking the diff disables traction control.

edit2: okay, this does sound like hill assist. https://youtu.be/VQTLFquSKPY. but, you can hear traction control kick in (the beeping)

 

[6wheelin]

if the "twanging" noise you're talking about is a rapid clicking coming from the dash, at about the height of the steering wheel, but to the left of the steering wheel.... I think this is traction control kicking in. would cause the throttle to cut out as well.

I've had this happen as well, which is why I'm interested in doing this mod:
http://www.toyota-4runner.org/engin...8882-new-fine-grained-vsc-off-mod-v6-1gr.html

Do a mod to bypass traction control? It's just easier to hold the brake versus spend $ to disable a function that should work.

my traction control seems to be way too sensitive on steep inclines.

I agree here. Mine is perhaps too sensitive.

edit: lock your center diff and see if it you can replicate the issue. locking the diff disables traction control.

edit2: okay, this does sound like hill assist. https://youtu.be/VQTLFquSKPY. but, you can hear traction control kick in (the beeping)

Yes this is the traction control, you can see the TC symbol in the right gauge flick on and off. My issue is from a dead stop.

Anyone know why the traction control does this? Is there a fix besides disabling? Is Toyota aware of this issue? Yeah I saw other posts about how the dealer will look at you with a stare and say "yes dumbass that's the traction control working" which isn't helping.