Is this normal in 4HI ??

[AlphaQup]

Alright, this just started happening and I'm feeling a bit paranoid. I don't know if it's normal or if it's been happening everytime it's in 4HI, but I'll give a little discription:

Sometimes when I change to 4HI from 2HI, I feel and hear a thud from underneath the car. I typically change while doing 15-20mph and this happens about 50% of the time. That didn't really worry me but then I started feeling and hearing a more prevelent thud. This thud only happens when im accelerating from a complete stop and also when im making a complete stop (while in 4HI only). It feels like being hit from behind by another car, but thats an over exaggerated statement. Does anybody out there know what I'm talking about, or have experienced this in their 4th gen? Should I take it to the stealership to have them monkey around on my rig? Or is it all normal? Any input would be greatly appreciated.

Nick

 

[jharris2]

IT's normal to have a bit of a thud when you shift to 4Hi on the fly. There have been prior discussions on the forum where it was mentioned that it's better to shift at a stop, if possible.

But the thud after you've shifted sounds worrisome.

 

[sharp4runr]

That you are hearing when accelerating sounds like the driveshaft clunk others have described. I hear lubing the driveshaft fixes it for a while but it does return. Do a search and you'll see what I'm talking about.

 

[mtnracer]

Yes, I have the thud as well. Lubing the front drive shaft fixes it for a while but it always comes back. I've heard that this has been an issue on 4Runners even since the 3rd Gen and carried over to the 4th Gen.

You can minimize it by sort of feathering the brakes when coming to a stop when in 4HI. This prevents the shaft from binding up und then thud'ing when the suspension uncompresses at the stop or first acceleration.

I've had my 4th Gen for about a year and I am almost used to it. I don't believe it can be stopped.

That you are hearing when accelerating sounds like the driveshaft clunk others have described. I hear lubing the driveshaft fixes it for a while but it does return. Do a search and you'll see what I'm talking about.

 

[Thai]

I believe that the Lexus GX470 also has this infamous clunk when you stop.

 

[schwalmy]

to what i know
it is not good to use 4hi or 4lo on dry pavement
nor is it good to shift on the fly
my manual (full time 4wd) says that if i wish to change form 4hi to 4lo i must be at a stop
schwalmy

 

[jharris2]

to what i know
it is not good to use 4hi or 4lo on dry pavement
nor is it good to shift on the fly
my manual (full time 4wd) says that if i wish to change form 4hi to 4lo i must be at a stop
schwalmy

It's OK to use 4Hi on dry pavement -- the V6 works the same as the V8 in 4Hi. Hurts gas mileage, but that's all.

4Lo is different. You have to be stopped and in neutral to shift to 4Lo.

 

[jharris2]

I believe that the Lexus GX470 also has this infamous clunk when you stop.

According to the service manager at the dealership, all the 4WD Toyotas have it -- he was complaining about it on his Tundra. Something about the design allows it to happen.

 

[sharp4runr]

nor is it good to shift on the fly

Manual states that it is ok to switch from 4WD to 2WD and vice versa below 62mph. Also instructions are printed on the driver's sunvisor saying the same. If things break because I'm switching on the fly, then I'm blaming Toyota because they've stated that it is ok.

Switching back and forth to 4Lo is different scenario. You have to be stopped and in Neutral otherwise the light will just blink and you'll hear a beeping noise.

 

[AlphaQup]

Thanks for all the input guys. I guess I'll just have to live with it. I'll have to look into the lubing thing.