Delay Shifting into 4HI

[smackitsakic]

Just curious as to why it sometimes takes our 07 SR5 (V6) a longer time than others to shift into 4HI?

It also takes random lengths of time to lock the diff. On Saturday night I was sitting in an empty, snow packed parking lot for over a minute trying to get the truck into 4HI then again to lock the diff.

Is there a secret to doing this quickly?

 

[GMZ]

Just curious as to why it sometimes takes our 07 SR5 (V6) a longer time than others to shift into 4HI?

It also takes random lengths of time to lock the diff. On Saturday night I was sitting in an empty, snow packed parking lot for over a minute trying to get the truck into 4HI then again to lock the diff.

Is there a secret to doing this quickly?

When it goes into 4wd the gears have to be aligned, and if you are stopped they may not be aligned properly. So if you are stopped try putting it in N or putting it in D and creeping fwd a bit.

 

[Zinarac]

One thing I've noticed is that the more often I use the 4WD components on my 2004 SR5, the quicker it activates 4HI, 4LO, and the center differential lock. I think the 4WD components just need to be exercised.

It used to take me about 30 seconds to switch from 2WD to 4HI. Recently, it has switched in a matter of seconds. I am usually rolling slowly in drive to allow the gears to align properly.

 

[Nuke]

I agree with exercising the 4WD mechanisms to help speed up the engagement time but I still don't like the delay. I miss my 2nd and 3rd gen's manual lever engagement and worry now with the 4th gen since I had instances with the other 4R's where I was in trouble and needed 4WD immediately.

 

[smackitsakic]

There still seems to be a more than lengthy delay in shifting...today I was at an intersection (icy at that) and was in 2WD. Traffic was busy and I was waiting for a clearing to pass. I flipped the switch to 4 HI and waited, and waited, and waited. I creeped forward, put it in neutral, etc. and it took a good 30 seconds before it would switch to 4HI and I could finally pass through the intersection.

What gives?

 

[scottm]

If the gears are sitting tooth-to-tooth, they can't mesh. If you drive perfectly straight forward, the gear associated with the front axle drive will turn exactly the same speed as the gear in the transfer case hooked to the rear axle, that doesn't help. If you steer left or right, the front wheels and gears turn a little faster than the rear, and the gears will eventually align tooth-to-valley and lock up. If you put the transmission in neutral, the gears have no torque holding them and they can rotate a few degrees to help align them.

So, it helps to turn a bit, and it helps to put it in neutral. And it helps to exercise the system occasionally to keep things loose.

 

[dpav02]

If the gears are sitting tooth-to-tooth, they can't mesh. If you drive perfectly straight forward, the gear associated with the front axle drive will turn exactly the same speed as the gear in the transfer case hooked to the rear axle, that doesn't help. If you steer left or right, the front wheels and gears turn a little faster than the rear, and the gears will eventually align tooth-to-valley and lock up. If you put the transmission in neutral, the gears have no torque holding them and they can rotate a few degrees to help align them.

So, it helps to turn a bit, and it helps to put it in neutral. And it helps to exercise the system occasionally to keep things loose.

Thank you SO much for this! This helps me understand this system A LOT...

I thought there was something wrong with my transfer case because my 2006 Sport sometimes would NOT shift into 4HI on the straight highway, no matter how fast or slow I was moving... But as soon as I'd turn, I'd hear a slight 'bump' and it would lock.

Your explanation makes total sense, I just wasn't thinking about it, but now I know how to get it to catch, just go slow and turn left to right a little until it catches.

THANK YOU

 

[having fun]

On top of stated above, change your fluids also.

 

[dpav02]

Just an update, I've been using the system regularly in my 2006 and now everything is super smooth and fast.

From getting into high, to low, to locking and unlocking the center diff.

I'm SO happy. Thanks to this forum (and Toyota manual, to be fair) it's like my truck is brand new with 105,000 miles!

Going to get the fluids changed later this spring once I have the cash.

 

[Martinjmpr]

One thing I've noticed is that the more often I use the 4WD components on my 2004 SR5, the quicker it activates 4HI, 4LO, and the center differential lock. I think the 4WD components just need to be exercised.

It used to take me about 30 seconds to switch from 2WD to 4HI. Recently, it has switched in a matter of seconds. I am usually rolling slowly in drive to allow the gears to align properly.

I've noticed the exact same thing. The more I use it, the quicker it shifts.

Remember that with our 4th gens, you can leave it in 4 hi unlocked and drive on hard, dry pavement all you want. So my technique is that if it looks like there's even a possibility of needing 4wd I go ahead and shift it into 4hi unlocked and drive it that way.

My thought is "better safe than sorry" and one of the reasons I got a 4th gen instead of some other vehicle was the multi-mode 4wd lets me do just this.

 

[BCfish]

It also helps to be moving about 10kmph when going between 2wd and 4hi IMHO. I know 4low you are supposed to be stopped and in N to shift to 4low from 4hi. 2wd to 4hi is a shift on the fly thing that works anywhere below 80kmph I know when sitting still and trying to get to 4hi from 2wd it takes a bit of forward or rearward movement.