4Hi -> 4Lo grinding/High Idle??

[Nelsonmd]

When I shift from 4Hi to 4Lo or back, I get a pretty strong sound and feel of gears grinding. Maybe this is normal and I should just push through it. It feels like the teeth of gears coming together with one moving, one not, and skipping a bit before biting for good.

Also, my Idle has been sitting around 1500. I seem to remember it being more like 700 when I first got the thing. What do you run at? If my idle is higher, then maybe that is why I get a worse feeling when shifting from Hi to Lo.

 

[cordrayj1]

ummmm. im pretty sure i dont "push through it" when i accidentlly grind my gears when shifting. i dont think anyone would recommend that. as far as the idle goes and speed you are travelling...just stop the vehicle completely. i have a 5 speed so its a little different situation, but the 4runners do idle high when you first crank em up.

 

[theizzardking]

i've had this happen try shifting the trans in neutral then pushing through if you still have grinding kill the motor shift into neutral and then shifting, this may be fixed by adding fluid to the t-case.

that idle does sound high though but like said above they do run high at start up for a while.

 

[Nelsonmd]

Yeah, I should check the fluid levels anyway. Haven't done that since buying it.

I have been putting it in 4lo to get it onto ramps to do work, so it is right after I turn it on. I will try leaving it running for a bit first.

 

[Gerdo]

My 4runner is a manual trans and I'm not sure if the 4runner auto/transfer is different but on other 4wd automatics that I have driven I always come to a complete stop then either put the trans in park or neutral then shift the transfer into 4 Lo, same coming back out.

The high idle is something different. Try resetting the computer. Disconnect the battery for a few minuets. (always disconnect the negative first, if you aren't taking the battery out then only disconnecting the negative is enough)

 

[g8rdmd]

I have an auto/slushbox...I noticed that shifting the 4wd caused grinding as well--completely solved by shifting trans into neutral first :banana:

 

[Mr. Leary]

I have an auto/slushbox...I noticed that shifting the 4wd caused grinding as well--completely solved by shifting trans into neutral first :banana:

x2.

You should neither be moving nor in gear when shifting from hi range into low range. You are litterally grinding your gears... which will eventually ruin your transfer case. This could be compounded by the fact that there may be no fluid in the transfer case. Check it immediately!

Letting the engine warm up will have no effect on this, except to slow down the idle, which will create less grinding... so its less grinding, but not fixing the problem. Ideally, you want to be shifting when there is no power being applied to the mechanism, such as when you are in N.

The high idle when the engine is cold is completely normal. However, if this keeps up it could be one of several things, including MAF, IAC, or mechanical problems with the top end (highly unlikely).

 

[turbodudey2]

To shift the t-case from high range to low, I always follow this procedure and never get any grinding:

1. Stop vehicle (foot on brake)
2. Shift trans to N
3. Shift t-case to N
4. Shift trans to P
5. Shift t-case to 4L

and then the same thing for going back to 2H.

Maybe it's because I have push button 4H, but for some reason just putting the trans in N it still would grind when shifting the t-case into gear... however, shifting the trans to P after the t-case is in N eliminated that.

 

[Nelsonmd]

Yeah, I always have the trans in N when I shift, and I always stop for a sec at N on the transfer case before shifting. I will try it in park and see if that changes it.

From 4H to 2H I don't worry about it. I don't have any sound or even any tactile feedback. It just shifts smoothly, even if moving.

I definitely need to check the fluid.

 

[Gerdo]

To shift the t-case from high range to low, I always follow this procedure and never get any grinding:

1. Stop vehicle (foot on brake)
2. Shift trans to N
3. Shift t-case to N
4. Shift trans to P
5. Shift t-case to 4L

and then the same thing for going back to 2H.

Maybe it's because I have push button 4H, but for some reason just putting the trans in N it still would grind when shifting the t-case into gear... however, shifting the trans to P after the t-case is in N eliminated that.

Putting the trans in N, the inerds can and are probably still spinning. Everything can spin from the trans fluid pulling on the gears since the torque converter always spins when the engine is running.

 

[driffter33]

I have an auto/slushbox...I noticed that shifting the 4wd caused grinding as well--completely solved by shifting trans into neutral first :banana:

:iagree:

 

[COShadow]

This seems to be a common problem. You can follow the procedure exactly (shifting into N) and still get the grinding. It been in other threads here before-- shift into park instead of neutral before shifting into 4 lo. You can also shift into N and then THROW the shift lever into 4 lo very quickly. You won't get grinding this way.

 

[Nelsonmd]

So I tried putting it in park this morning to shift it, totally solved it. No sound or grinding at all.

Thanks for the tips guys.