Binding then "pop"
 

My 2000 SR5 4WD has developed a very disturbing behavior. It has a CDL button on the dash (left of the steering wheel), but I've never used it or really tested it out at all.

The truck is being used by my daughter @ college in western NC. She has been shifting between H2 and H4 this past winter as the conditions there have changed from snow/ice to dry surfaces and back to snow/ice. (This truck does not have the automatic 4WD button on the side of the 4WD shifter because it is an SR5 not Limited.) She has not used the CDL button at all, and I'm pretty sure it is OFF.

What happens is that when she puts the truck in Drive, the transmission will drop into gear, but when she presses on the gas pedal, it doesn't move until the rpms get up to about 1500 then something "pops" and it will lunge forward. Even when moving forward it seems like there is resistance. Also will do this in Reverse.

I visited her this weekend and verified this strange behavior. I checked the shifting from 2WD to 4WD and it doesn't always disengage the front driveshaft when in the 2WD position (and the green 4-wheel symbol on the dash will stay lit).

Is my center diff blown?

Axle seal leaking? They'll swell the brake shoes and stick.

Nope rear axles show no signs of leaking. Inside surface of rear tires are dry. That is one thing I always look for. Maybe my rear pumpkin has gone dry somehow? I saw no leaking back there, but didn't have a way to check the level.

Auto transmission fluid level is correct.

:keyboard:
Are you or her shifting from LO/HI while the vehicle is moving?

Have you ever routinely shifted from LO/HI while the vehicle is in motion?


My question is based on the assumption you are referring to the hand lever to mechanically shift from HI/LO while already in 4WD.

The owners manual says that it is ok to shift HI/LO while in motion. What the owners manual says should not apply to 4Runners with many miles.

I have 97 Limited and it has the engage 4WD button on the HI/LO lever.

I don't have the button on the HI/LO lever, that's on Limited only not SR5. The HI/LO shifter is "shift on fly" and I've done it a few times before just to test it.

.
The reason why I ask about the "shift on the fly" is because when some 4Runners get a lot of miles of them, shifting between 4WD HI/LO while driving will result in a terrible grinding sound as the gears hit. If you hear any grinding at all and "just force it" repeatedly you can destroy those gears and you 4WD will be kaput. I am not sure if that is what happened in your case but if your problems are only in 4WD and not 2WD then you probably have major issues in the transfer case.

On my truck, ever since 100,000 I have not been able to shift on the fly HI/LO without stopping first. If I even try, there is a grinding noise and it sounds terrible.

I asked my mechanic who only work on Toyotas about this and his explanation is that while the factory design is "shift on the fly", if you notice that it grinds IN ANY WAY then don't force it or you will damage the transfer case. He then went on to tell me about a customer who broke his 4WD two times because he didn't realize this and just forced it to shift despite the grinding sound. This damage can occur even if you are on snow or in mud, it has to do with the age (miles) of the drivetrain.

This explanation might not apply to your truck. I don't know how a 4Runner without the button goes from 2WD to 4WD. The issue I am talking about only has to do with switching 4LO/4HI while moving. I am able to engage the 4WD via the button without any issues and I assume the non-Limited trucks can do this as well.

:lookout:

Yes, my daughter did have problems with it grinding once this winter, but I had her stop the truck and shut it off and shift while the truck was still. She was only in a parking lot when she tried to shift from 4WD to 2WD when the grinding happened.

I don't know if she tried the 2WD/4WD shift after that (she was afraid to after that), but now it seems the transfer case (sorry, not the center diff) is having big problems.

Anyone have an estimate on a transfer case rebuild?

I don't recall the 2000 model having a CDL switch. Does your 4runner have a J-shifter for the transfer case? Something is askew about this.

As for the problem. I think it is mechanical, ( SR5 anyway) Once you move from 4wd hi to 2wd hi - That is it, no delay or anything. Now your ADD might take a moment to disconnect and this is a reason why your 4x4 light takes a long time to turn off.

As for the delay, it might be the transmission is going out.

If you have an SR5 - 2000 model, you don't have a center diff.

I have a transfer case (if it is the problem) that i will sell to you installed for $300. Works great and has no leaks.

I'll look in the morning to be sure, but I got on a t-case out of a early 99. Plain jane style without the actuator(on the back). I live in Va. and I will be going to OBX this coming Sat. Pm me if interested. $100. Singtoe is closer and will install though.

.
so it is still up in the air if it is the tranny or the transfer case....

Yes, there's a J-shifter, but no '4WD' button on the side like my Limited. There's no delay of the transmission dropping into gear, the delay is that when you push on the gas, you can feel the truck WANTS to go forward but can't (like the brakes are on or you're pulling a heavy load) then there's a "POP" and it takes off.

There is a button on the dash left of the steering wheel that says 'DIFF LOCK' or something similar.

I'm interested in your transfer case, installed, I'll give you a call.

It does sound like it is the transfer case. It sounds like one of two things, a bent shift fork and the transfer case is trying to engage hi and lo at the same time or the other thing that it could be is that there is a chain that transfers power from the main shaft to the front drive shaft (also in the transfer case) and it might be slipping off the drive sprockets causing binding and then the sudden pop.

PM'd you my cell... Only problem is getting here from Boone.