4WD won't engage for use in our 14" of snow. Pretty embarrassing almost getting stuck when accords are whizing right by. I locked the hubs and the 4WD light comes on when the button is pressed, but only the back wheels are getting power. Any suggestions? This is my first winter with the car and never have tried 4WD in it before. Thanks.
4WD Issues - FJ62
- Thread starter tnw
- Start date
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Basic scheme of how it works:
Psh the butto and it accuates the solinoid on the firewall on top on the pass side. It is brown, green and black with 2 hoses going out of it and one going into it as well a few ele connectors. It is just a push/pull actuator. It pulls and forces the plunger in the transfer case to allow the hub to engage the splines and give you 4 WD. Hi/Low is controlled by the stick on the floor.
Put it in N and push the switch. Reach under and grab the FT drive shaft and see it it rotates. It should not. Check out all the vac lines going from the solinoid to the to the TC adn the input side line to the solinoid. I think there is a filter in line with the input side that might be clogged. If all is good pull the hoses to the TC off of the solinoid and have a friend push the switch on and off and verify that you are generating vacume out of one port then another. If only one port works it may be possible to flip the hoses and engage the 4WD. If no vc from either one check connections and then look at keil Thomsons write up on how to replace it chaep. If you get vac from both ports go below and check the same thing on the 2 larger vac hoses that go into the TC. If different results then you might have a bad hard line between it and the noid. If the hoses are good and the vac checks out you might not have enough vac to get it to engage. Use a mighty vac and try sucking on each line in turn and see if that will get you in/out of 4WD. If it does go back to the noid. If it does not or if it will not hold vac then you may have an internal leak in the vac diagphram on the case. It should hold vac. If all else fails take off the the vac diagphram from the TC You can get in there and move it into 4WD by hand. It it still wont go then it may be a TC issue. It could also just be gunked up on the piston end of the TC requiring more vac then supplied to engage.
One possible easy fix is to unlock the ft hubs and hit the switch then just drive around a while. The vas might eventually pull the sleeve over the ub. You will hear it chatter when it tries to go in; just hit the button and it will stop. Do this a few times and it might free it up.
Psh the butto and it accuates the solinoid on the firewall on top on the pass side. It is brown, green and black with 2 hoses going out of it and one going into it as well a few ele connectors. It is just a push/pull actuator. It pulls and forces the plunger in the transfer case to allow the hub to engage the splines and give you 4 WD. Hi/Low is controlled by the stick on the floor.
Put it in N and push the switch. Reach under and grab the FT drive shaft and see it it rotates. It should not. Check out all the vac lines going from the solinoid to the to the TC adn the input side line to the solinoid. I think there is a filter in line with the input side that might be clogged. If all is good pull the hoses to the TC off of the solinoid and have a friend push the switch on and off and verify that you are generating vacume out of one port then another. If only one port works it may be possible to flip the hoses and engage the 4WD. If no vc from either one check connections and then look at keil Thomsons write up on how to replace it chaep. If you get vac from both ports go below and check the same thing on the 2 larger vac hoses that go into the TC. If different results then you might have a bad hard line between it and the noid. If the hoses are good and the vac checks out you might not have enough vac to get it to engage. Use a mighty vac and try sucking on each line in turn and see if that will get you in/out of 4WD. If it does go back to the noid. If it does not or if it will not hold vac then you may have an internal leak in the vac diagphram on the case. It should hold vac. If all else fails take off the the vac diagphram from the TC You can get in there and move it into 4WD by hand. It it still wont go then it may be a TC issue. It could also just be gunked up on the piston end of the TC requiring more vac then supplied to engage.
One possible easy fix is to unlock the ft hubs and hit the switch then just drive around a while. The vas might eventually pull the sleeve over the ub. You will hear it chatter when it tries to go in; just hit the button and it will stop. Do this a few times and it might free it up.
Put the t-case in 2hi and lock the hubs. Crawl under the rig and try to turn the front drive shaft. If you can turn it one or both of your hubs aren't engaging. Had the same problem on a customers rig when the cold weather hit. Grease got to stiff in the cold. Disassembled, cleaned, and regreased hubs worked fine.
yooper
SILVER Star
I agree, sounds like your hubs aren't engaging. The switch that turns on the 4WD light is inside the transfer, so you can be 99% sure that 4WD is properly engaged there if the light is on. The hubs are pretty easy to take apart, clean out, and reassemble, but it's not very intuitive how the springs and stuff go back in, so pay attention to how it comes apart. The Factory Service Manual has a nice description that makes it easy. If you don't have an FSM, get one from Toyota Publications - it's the best investment you can make in your truck.
yooper
SILVER Star
I just realized that we are all assuming here that you knew to lock the hubs - if not, look at the center of each your front wheels at the hub- there is a dial there that you have to turn to the "lock" position BEFORE you switch into 4WD. So if you didn't lock them, press the 4 Hi button, drive until the 4WD light goes out, pull over, lock the hubs, and get back in and press the button again.
I leave my hubs locked all winter. The only downside to that is slightly worse gas mileage and slightly more wear on the front axle parts. It's all worth it when I need to switch into 4WD in a hurry on a snowy/icy road though.
Good luck!
I leave my hubs locked all winter. The only downside to that is slightly worse gas mileage and slightly more wear on the front axle parts. It's all worth it when I need to switch into 4WD in a hurry on a snowy/icy road though.
Good luck!
- Thread starter
- #6
Thanks to all of you for the replies. Another 8" of snow this morning. Tried relocking the ubs and then drove for a while in 2WD. Pushed the 4WD button while moving and light came on and there was a quick grinding noise in the transfew case. But, then tried to go up a pretty easy snow covered hill and got stuck. Only one wheel moving in back. Finally made it through after a few tries. These should be better in the snow, right? Is there a problem with the differentials?
DO NOT push the button when moving at speed. Stop the truck then push it, that grinding was the 4 wheel drive attempting to engage with moving gears. I believe one of plaques on the dash says that you can under 45 mph, but I haven't seen it work yet.
Based on your description of the grinding noise when you pushed the dash button while moving the truck I would say that one or both of your hubs is not engaged. If they were engaged there would have been mininal grinding because the front driveshaft would have been turning. This same problem was discussed here a few weeks ago. Even if the hubs is turned to the locked postion it may not be engaged. It is probably frozen from the cold. Get a heat gun or hairdryer and warm up the hubs. With t-case in 2wd you can turn the front driveshaft with your hand. When it stops turning the hubs have both engaged.
Good luck
Good luck
It will grind if the hubs are locked or if they are unlocked. I should make no difference. The issue is with the drive shaft. You can lock the hubs and it will not turn if both hubs are locking. If one hub is locking it will turn but usually with more resistance. If you hit the 4WD button and you can turn the shaft then the issue is in the TC . The hubs either work or they dont; the TC is known for not engaging. As I said above it is a real easy test. Push the button with the hubs unlocked. if the shaft turns it is the TC if it does not, release the button and lock the hubs. The shaft should not turn.
yooper
SILVER Star
But it's pretty hard to think of a scenario when the light could go on and the transfer's not engaged. The switch for that light is on the fork inside the transfer that actually moves to engage the front drive. If the light's on then the transfer is engaged for 4WD.
Mine doesn't grind at all. Ever. EXCEPT for the one day that I forgot to lock one of the hubs because I got distracted - nasty grinding noise.
My owners manual states that I can shift into 4WD at "any speed".
I bet it's the hubs.
tnw: If one rear wheel was spinning and the other not, that's normal differential behavior. The spinning wheel had no traction. The solution to this is a locking differential, which your truck doesn't have.
Do this: in 2WD according to the light, with hubs apparently locked, reach under and see if you can turn the front driveshaft by hand. If so, then one or both of your hubs isn't really locked.
Mine doesn't grind at all. Ever. EXCEPT for the one day that I forgot to lock one of the hubs because I got distracted - nasty grinding noise.
My owners manual states that I can shift into 4WD at "any speed".
I bet it's the hubs.
tnw: If one rear wheel was spinning and the other not, that's normal differential behavior. The spinning wheel had no traction. The solution to this is a locking differential, which your truck doesn't have.
Do this: in 2WD according to the light, with hubs apparently locked, reach under and see if you can turn the front driveshaft by hand. If so, then one or both of your hubs isn't really locked.
Yooper, I really am not trying to argue a point here. It might very well be the hubs but if you leave them un locked, hit the switch and the ft shaft turns by hand then it is the TC. I can think of quite a few ways the light can come on and the TC will not engage.
I am not sure how the light gets powered. I think it is powered from the dash and comes on simply when you push it, bascially an idiot light to remind you you are in 4WD. It might require the switch on the TC to engage or some sort of feedback from the solinoid. I have seen then go into 4WD with the switch pushed and the light not come on but the lamp was not burnt out which reinforces the idiot light theory.
Either way it is a simple check to figure out if it is the TC or the hubs.
I am not sure how the light gets powered. I think it is powered from the dash and comes on simply when you push it, bascially an idiot light to remind you you are in 4WD. It might require the switch on the TC to engage or some sort of feedback from the solinoid. I have seen then go into 4WD with the switch pushed and the light not come on but the lamp was not burnt out which reinforces the idiot light theory.
Either way it is a simple check to figure out if it is the TC or the hubs.
The fact that it grinds going into 4 tells me the hub or hubs are not working correctly. If the hubs are engaged the front shaft will be turning and the t-case will slide into 4 without any trouble, of course, assuming you were not spinning the rear tires when you tried.
One tire spinning is proper open diff operation. To eliminate this problem install a locker. If you live around snow you probably don't want an auto-locker because both tires will spin when you don't want them too. Put in a selectable locker like an ARB so you can engage when needed and disengage at will. You'll have much better control that way.
It is possible for the t-case to engage and the light stay off.
One tire spinning is proper open diff operation. To eliminate this problem install a locker. If you live around snow you probably don't want an auto-locker because both tires will spin when you don't want them too. Put in a selectable locker like an ARB so you can engage when needed and disengage at will. You'll have much better control that way.
It is possible for the t-case to engage and the light stay off.
yooper
SILVER Star
[quote author=dd113 link=board=1;threadid=10873;start=msg98297#msg98297 date=1075782196]
Yooper, I really am not trying to argue a point here....I am not sure how the light gets powered. [/quote]
It's cool DD!
I AM sure that the switch for the light is in the transfer case, part number 84222-60021, "SWITCH, TRANSFER INDICATOR #1". It's not just an idiot light - to prove it to yourself, watch it sometime in your own FJ62 - you will notice that in those situations when the transfer doesn't engage right away (like accelerating uphill), the light won't go on right when you press the button, but goes on when the transfer actually engages. Same thing for when the light goes off - it doesn't happen until the transfer actually disengages. This is a useful indicator light!
Yes, the transfer can be engaged and the light be off, if either the either switch (inside the transfer), wires, or bulb are broken. What is very unlikely is to have the light on with the transfer not engaged. I suppose there could be a short circuit somewhere, especially on a 14+ year old truck.
Should we make a bet re: tnw's truck?
I bet it's the hubs! 
Yooper, I really am not trying to argue a point here....I am not sure how the light gets powered. [/quote]
It's cool DD!
I AM sure that the switch for the light is in the transfer case, part number 84222-60021, "SWITCH, TRANSFER INDICATOR #1". It's not just an idiot light - to prove it to yourself, watch it sometime in your own FJ62 - you will notice that in those situations when the transfer doesn't engage right away (like accelerating uphill), the light won't go on right when you press the button, but goes on when the transfer actually engages. Same thing for when the light goes off - it doesn't happen until the transfer actually disengages. This is a useful indicator light!
Yes, the transfer can be engaged and the light be off, if either the either switch (inside the transfer), wires, or bulb are broken. What is very unlikely is to have the light on with the transfer not engaged. I suppose there could be a short circuit somewhere, especially on a 14+ year old truck.
Should we make a bet re: tnw's truck?
I bet it's the hubs! - Thread starter
- #15
OK...it seems to be a problem with the hubs. I reached under and turned the front drive shaft freely when the vehicle was in 2WD and the hubs were suppossedly locked. I also engaged the 4WD and tried to spin the shaft....won't budge. So, the problem appears to be the hubs. I tried heating them up a bit with a heater, but I still couldn't get them to engage. Are hubs easy to take apart and clean myself, or do the ygenerally just get replaced.
Thanks in advance. You guys are helping me out BIGTIME!!!
Thanks in advance. You guys are helping me out BIGTIME!!!
yooper
SILVER Star
As the yooper pointed out..DO NOT OVER GREASE THE LOCK OUT!
This is a very common mistake made. There is no reason to have a massive amount of grease in them. A light coating is best.
Good luck!
-Steve
This is a very common mistake made. There is no reason to have a massive amount of grease in them. A light coating is best.
Good luck!
-Steve
Too much grease can stop the free movement of the splined engagement collar.
yooper
SILVER Star
[quote author=dd113 link=board=1;threadid=10873;start=msg98978#msg98978 date=1075903516]
No matter how many times you prove me wrong I will go to my deathbed insisting it was the TC
The magic elves that conspire against me fixed his case during the night and broke his hubs.
[/quote]
No matter how many times you prove me wrong I will go to my deathbed insisting it was the TC
The magic elves that conspire against me fixed his case during the night and broke his hubs.
[/quote]
