Hit a huge pothole, 4Runner went into 4lo ...Anyone know why?

[Climb14er]

This winter left Denver with some huge potholes, and I've been fairly lucky... until last night.

I was in the right lane and all of a sudden the front right tire went down and hit a huge pot hole. Man, was I surprised!

The V8 was going about twenty mph and after hitting it, I slowed down and noticed there was a lower gear effect taking over.

I pulled over to a side street and sure enough, it felt as if the 4Runner in a lower gear.

I began to drive some more and it wouldn't shift to out of 4th gear into OD.

I took her on the freeway for a short exit and it wouldn't go into 5th.

I pulled to a side street and put it into 4lo and drove a bit. This felt more like 4lo with much lower gearing.

I shifted back and forth from 4hi to 4lo, and all of a sudden, something felt as if it loosened and the 4Runner was once again driving normally and into 5th/OD.

Anyone have any ideas what might have occurred?

Could the jolt to the right tire have affected the mechanism that goes from 4hi to 4lo?

I looked and there's no damage that I could see (luckily) and it's not pulling to the left or right.

I might be hearing the engine growl a bit more but this could be my imagination.

This has got me perplexed.

Any thoughts?

 

[pat161]

Not sure what happened but if you took it on the freeway and got up to speed you were definitely not in 4lo. Is it possible that you knocked it out of O/D, I have an 02 w/ the button on the shifter so I could see it happening, not sure if its as likely on a 4th gen as I don't know where that button is.

 

[Climb14er]

Not sure what happened but if you took it on the freeway and got up to speed you were definitely not in 4lo. Is it possible that you knocked it out of O/D, I have an 02 w/ the button on the shifter so I could see it happening, not sure if its as likely on a 4th gen as I don't know where that button is.

I'm surprised there are no more replies for the question I presented when there are so many knowledgeable folks on this forum.

Unfortunately, there's no override on the V8.

I spoke with Toyota and got the info I needed.

It's the 'fly by wire' that took over from the mechanical side of the operations.

There might be 'new codes' in the computer from what occurred.

There are other things the team leader mentioned but I won't be posting them.

Basically, he doesn't like the 'fly by wire' system!

I'm going to monitor the vehicle to see if any problems ensue.

 

[gizmopt2002]

I don't like the drive-by-wire system either. I can see that a bump that huge can cause some odd problem to happen.

 

[spud72]

Wow - if it was big enough to do that to a 4Runner, just imagine what it would have done to a car!

 

[Uneek]

There is an overdrive on the 4Runner. D will allow the transmission to shift upto overdrive. If you click over 4, it would be the same as driving it with the overdrive button off.

 

[JB.]

There are other things the team leader mentioned but I won't be posting them.

Basically, he doesn't like the 'fly by wire' system!

Why would you not want to post them? We don't know who you talked to.

As far as the overdrive thing, it just sounds like the shifter got nudged over into 4th. Any other slowing sensation could have been a big chunk of ice interfering with the free rotation of a wheel before dislodging.

 

[Climb14er]

Re: Re: Hit a huge pothole, 4Runner went into 4lo ...Anyone know why?

As far as the overdrive thing, it just sounds like the shifter got nudged over into 4th. Any other slowing sensation could have been a big chunk of ice interfering with the free rotation of a wheel before dislodging.

The only place the shifter was in all along, after the pothole was the same place it was at the beginning and nothing moved there.

The way the computer so-called 'learns' the habits of the driver and commits them to memory is a negative in the opinion of the team leader and me.

There were aspects of the computer fly by wire system that removed power and hindered my ability to get the 4Runner back to 'normal' in a short amount of time.

It appears as if the system had to go through some type of 'shut down and re-boot' to allow me to gain the type of control I had prior to the system's reducing the options I had right after the 4Runner hit the pothole.

The reduced power and inability to go to 5th gear was extremely frustrating and kind of nerve wracking in the sense that I thought either the tranny, the transfer case or the CVG joint or something else mechanical was broke!

What the computer did was at first shut down the energy from the vehicle and slowly bring it back up.

Who knows if my moving the vehicle from 4hi to 4low, back and forth had anything to do with getting back to speed.

The whole shutdown and reduced power 'episode' lasted about twenty minutes.

The team leader and techs who helped diagnose what occurred all agreed that if I had the ability to mechanically drive the 4Runner 'normally w/o the compuyter override, the whole reduced power episode would never have escalated.

All said, this 4Runner is TOUGH! If any other car had hit the pothole the way the 4Runner did, it would have been crippled.

The 4Runner ROCKS, even with the fly by wire system. :

 

[JB.]

Re: Re: Re: Hit a huge pothole, 4Runner went into 4lo ...Anyone know why?

..The 4Runner ROCKS, even with the fly by wire system. :

Thanks for the detail. I'm interested because I suspect electronic throttle control is at the center of the odd behavior of my truck in <a href="http://www.toyota-4runner.org/showthread.php?threadid=17181&highlight=throttle" target="_blank">this</a> thread so I'm always alert to anyone having strange symptoms possibly involving the drive by wire system.

You're right, though. 4Runners are very tough.

 

[Kmvreter]

Re: Re: Re: Hit a huge pothole, 4Runner went into 4lo ...Anyone know why?

... The way the computer so-called 'learns' the habits of the driver and commits them to memory is a negative in the opinion of the team leader and me.
... What the computer did was at first shut down the energy from the vehicle and slowly bring it back up.

Who knows if my moving the vehicle from 4hi to 4low, back and forth had anything to do with getting back to speed.
...

Did the check engine light (MIL) come on? If the drivetrain goes into safe or limp home mode then it might (or should) throw an engine or transmission code and turn on the MIL. Did the service guys mention a code or document it on the repair order?