4x4 not working again
- Thread starter Mirror
- Start date
Gerbil21
Member
- May 28, 2014
- 839
it may be wiring, any lights on or off on the dash or selector switch and did you try turning the car off and on again, after the tccm senses a fail in the system it gives up and wont try again so cycling ignition on and off may help. also can you hear the front disconnect?Mirror said:
Mounce
Member
What do you have the switch set on?
I don't know much about the 4wd systems but if I remember right, A4WD would do something like what you're describing.
I don't know much about the 4wd systems but if I remember right, A4WD would do something like what you're describing.
- Jan 27, 2014
- 335
Just got home and did some basic tests on a flat ice covered back lane with some small drifts on it.
without ever shutting off the vehicle, i put the truck in reverse and let go of the gas pedal to make sure the rear tires wouldn't pull me backwards, then switched to N put it in 4 low. back into reverse, the truck started pulling backwards. Did the same thing again with 4 high. Same results. which means the 4x4 is engaging.
so i drove into the snow drift in 2hi, stopped, then let go of the brake, truck wouldn't move. back to N, then into 4low. back into drive/reverse and the truck started pulling itself out. but when i pushed hard on the gas back tires would spin and i could feel the front grab and let go or at least that's what it felt like with just a tiny bit of snow being pushed up from the front tires.
No lights are on, on my dash except my abs light due to a speed sensor being broken.
without ever shutting off the vehicle, i put the truck in reverse and let go of the gas pedal to make sure the rear tires wouldn't pull me backwards, then switched to N put it in 4 low. back into reverse, the truck started pulling backwards. Did the same thing again with 4 high. Same results. which means the 4x4 is engaging.
so i drove into the snow drift in 2hi, stopped, then let go of the brake, truck wouldn't move. back to N, then into 4low. back into drive/reverse and the truck started pulling itself out. but when i pushed hard on the gas back tires would spin and i could feel the front grab and let go or at least that's what it felt like with just a tiny bit of snow being pushed up from the front tires.
No lights are on, on my dash except my abs light due to a speed sensor being broken.
- Jan 27, 2014
- 335
Cant seem to find anything on a google search about 4x4 and speed sensors.
On a plus side after a chevy 2500 yanked me out, two hard pulls to get me out. My PRND321 lights on the dash came back on.
On a plus side after a chevy 2500 yanked me out, two hard pulls to get me out. My PRND321 lights on the dash came back on.
djthumper
Administrator
marinegrunt
Member
- Oct 13, 2012
- 110
I had similar issues with ours Envoy. At first, the 4wd would sometimes engage and sometimes it wouldn't. There were times it would seem to pop in and out. 4 lo worked when 4 hi didn't but eventually lost 4 lo too. When I had it completely up on jack stands the 4wd would engage but only after really getting on the throttle. I tested it out in the wet grass and there was no 4wd at all under load. I first tried messing with the disconnect. I installed new bearings and put new grease in. The gears are in great shape. I also installed a new actuator. Then figured that it was the clutches in the transfer case but that wasn't the reason either. I finally decided to try and manually engage 4wd by removing the actuator and pushing on the fork in the disconnect with a long extension. It took a lot of force and I could tell that the splined collar didn't want to mesh properly with the other gear. I did this by jacking up the vehicle, front and rear, removing the actuator but leaving the harness hooked up, key turned on but not started, and selecting 4hi. I ended up making a little gadget that would manually engage the disconnect so I could at least narrow down the issue. (I'll post a pic). After doing so the 4wd now works fine. I really don't see how the disconnect could be the issue because I basically rebuilt it. What I think is going on is that the bearings in the front diff, especially on the intermediate shaft, are bad. I figure if there's a slight wobble in the intermediate shaft that would keep the splined collar in the disconnect from wanting to slide over the other inner gear.
If I were you, after doing what others have recommended, I'd try and jack the vehicle up and manually engage the disconnect. Do so by leaving the key on and engine off. Select 4hi, remove the actuator but leave it hooked up to the harness. Press on the fork, or where the actuator plunger pushes, with a long extension while turning the tire by hand. The reason behind this is too see how hard it is to get the splined collar to slide over the internal gear. If it doesn't slide right over I would then rig up a way to where it's always manually engaged. You then have to be sure to wire the actuator up and in a safe place before test driving. Like I already mentioned, mine just doesn't want to mesh up. That could explain why it was jumping in and out of 4wd.
Here's the gadget I made to ensure that 4wd was engage. I used a piece of steel and a small piece of 3/4" black pipe. You could probably even use a piece of 1/4 plywood or a piece of plexi glass. Then used a piece of 3/4" pvc. It would be easier to work with. I ended up welding the pipe to the plate steel because I plan on just leaving mine for the time being. If you're just using it for troubleshooting just make it out of something basic and materials easy to work with.
One other thing, I remember someone saying that there are times it seems like the front actuator is working. You can hear it whining, and when removed, you see the plunger extending but the plunge isn't extending as long as it should. If you end up needing one you can get one on Amazon for $50 rather than spending $100 at the local parts stores.
If I were you, after doing what others have recommended, I'd try and jack the vehicle up and manually engage the disconnect. Do so by leaving the key on and engine off. Select 4hi, remove the actuator but leave it hooked up to the harness. Press on the fork, or where the actuator plunger pushes, with a long extension while turning the tire by hand. The reason behind this is too see how hard it is to get the splined collar to slide over the internal gear. If it doesn't slide right over I would then rig up a way to where it's always manually engaged. You then have to be sure to wire the actuator up and in a safe place before test driving. Like I already mentioned, mine just doesn't want to mesh up. That could explain why it was jumping in and out of 4wd.
Here's the gadget I made to ensure that 4wd was engage. I used a piece of steel and a small piece of 3/4" black pipe. You could probably even use a piece of 1/4 plywood or a piece of plexi glass. Then used a piece of 3/4" pvc. It would be easier to work with. I ended up welding the pipe to the plate steel because I plan on just leaving mine for the time being. If you're just using it for troubleshooting just make it out of something basic and materials easy to work with.
One other thing, I remember someone saying that there are times it seems like the front actuator is working. You can hear it whining, and when removed, you see the plunger extending but the plunge isn't extending as long as it should. If you end up needing one you can get one on Amazon for $50 rather than spending $100 at the local parts stores.
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no, but your front axle will be permanently engaged, will use a bit more mpg and a bit more wear on the diff, but no ill effects. Some of the offroad fellas have swapped the AWD spline connector which is essentially the same as manually engaging it.Mirror said:
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
marinegrunt
Member
- Oct 13, 2012
- 110
I mentioned engaging it manually more for troubleshooting than anything. If it is then working that would at least rule out the transfer case clutches and any major issue in the front diff. Mine was doing pretty much the same thing yours is doing but it works with it manually engaged. I'm really leaning towards the intermediate shaft bearings or bushings. I'm thinking there's play in the intermediate shaft and it's not allowing the splined collar to mesh. I could tell it didn't want to mesh from when I engaged the disconnect on my own using a long extension. I really had to push on it and could feel the teeth on the splined collar jumping. I installed new bearings in the disconnect and the gears are in great shape. I also replaced the transfer case thinking it was the clutch pack. I'm going to pull the front diff once winter is over. I heard by leaving it manually engaged you lose about 1 mpg. The wife only drives it a mile to work each day so that's why I figured I'd wait until after winter and she no longer needs 4wd.
If the speed sensor doesn't do it, remove the actuator and try to manually engage the disconnect just to see how easy it engages. If it's touch to engage you could be having the same issue I'm having. It's also possible it could be the clutches in the transfer case.
If the speed sensor doesn't do it, remove the actuator and try to manually engage the disconnect just to see how easy it engages. If it's touch to engage you could be having the same issue I'm having. It's also possible it could be the clutches in the transfer case.
- Jan 27, 2014
- 335
Ok, well I just followed that chart on the link above, and everything was a no except the first which is a yes, which points to the disconnect again. I put the truck on the ground, backed up into snow, made sure the truck wasn't able to move with engine idle while in snow in drive or reverse with 2HI on. Put it into 4 low, heard noises then the clunk and put it in drive and reverse, both times the truck pulled itself out. But as soon as I put engine power using the gas pedal, i can't get the front tires to turn. Makes no sense. But I did see this on both cv axels which are both brand new, installed when i put the new disconnect in.
Passenger side -
Driver side -
Passenger side -
Driver side -
- Jan 27, 2014
- 335
Well we did the check on the disconnect. I push in on it and when we turn the tire, the disconnect tries to connect but pushes in and out and wont lock. As for the cv axels, we are replacing them since both of the retaining straps on the back are loose now. Then we will take apart the disconnect and see if everything inside is ok. If so we will regrease with -50 grease.
marinegrunt
Member
- Oct 13, 2012
- 110
That's exactly what my disconnect was doing. I could feel the gears on the splined collar kind of skipping off of the internal gear. I took my disconnect apart 3 times and even installed new bearings. The gears are in perfect shape as is the shift fork. The new bearings fit in really tight so I know the bushings are okay. That's why I made that little gadget to manual lock it on. I mainly wanted to make sure my 4X4 work if it was engaged.
I'm wondering if the problem could possibly bearings in the diff for the intermediate shaft? My thinking is if that shaft has a little play the internal gear in the disconnect might be a tad off? But, if I installed new bearings in the disconnect wouldn't it hold the intermediate shaft in place? I guess if the bearing at the opposite end of the shaft has play it could still wobble a tad. I've heard it doesn't take much for the gears to be off.
I decided to leave that manual gadget in for now just to get through winter. Once the snow is gone I'm going to pull the diff and replace the bearings. I'd like to get others opinions on this problem though. I kind of wondered if it could still be my disconnect even though it has new bearings and looks good but since yours is basically brand new there has to be some other issue.
If you want me to make you one of those gadgets to use for the time being let me know. I'd be more than happy to make one and mail it out to you. I notice no difference in 2hi and haven't noticed any drop in gas mileage. I drove 125 miles today and the gas mileage was the same as what it normally is. Other factors may have came into play though.
If you figure out the problem please keep me posted and I'll do the same.
I'm wondering if the problem could possibly bearings in the diff for the intermediate shaft? My thinking is if that shaft has a little play the internal gear in the disconnect might be a tad off? But, if I installed new bearings in the disconnect wouldn't it hold the intermediate shaft in place? I guess if the bearing at the opposite end of the shaft has play it could still wobble a tad. I've heard it doesn't take much for the gears to be off.
I decided to leave that manual gadget in for now just to get through winter. Once the snow is gone I'm going to pull the diff and replace the bearings. I'd like to get others opinions on this problem though. I kind of wondered if it could still be my disconnect even though it has new bearings and looks good but since yours is basically brand new there has to be some other issue.
If you want me to make you one of those gadgets to use for the time being let me know. I'd be more than happy to make one and mail it out to you. I notice no difference in 2hi and haven't noticed any drop in gas mileage. I drove 125 miles today and the gas mileage was the same as what it normally is. Other factors may have came into play though.
If you figure out the problem please keep me posted and I'll do the same.
- Jan 27, 2014
- 335
Ok so we regreased the inside with -50 grease, all gears and bearings are fine. We can get the disconnect to engage with around 45 to 55 lbs of force. But the push rod on the actuator only takes between 10 and 15 lbs of pressure to push in. Has anyone else tested the push rod on the actuator to see how much lvs it takes to push in? (Turn on 4hi then disconnect actuator, push rod stays out)
Btw, with doing this, I can still switch from 2hi to 4x4. Just that in 2Hi, the two front tires are connected to eachother but no powered, then switch to 4hi/4lo the transfer case engages and now it's in 4x4.
This is our version of what you built,
And this is what I did with the actuator so I don't get the 4x4 not working light:
Btw, with doing this, I can still switch from 2hi to 4x4. Just that in 2Hi, the two front tires are connected to eachother but no powered, then switch to 4hi/4lo the transfer case engages and now it's in 4x4.
This is our version of what you built,
And this is what I did with the actuator so I don't get the 4x4 not working light:
That's one of the better fixes I've seen for that thing. I like the fact that it's 'reversible', the 4WD doesn't have to be on all the time, and pretty easy to engage and dis engage.
Can you mark the bolt so you know when to stop turning it?
Can you mark the bolt so you know when to stop turning it?
HARDTRAILZ
Moderator
- Nov 18, 2011
- 49,665
- Jan 27, 2014
- 335
My 4x4 stopped working again yesterday when i burried my rear driverside tire half way up in gravel. I tightened the bolt a quarter turn and 4x4 worked perfectly and pulled me out without a problem.
Now my question is, can the insides of the disconnect be purchased seperately? I may want to convert the gears to the awd unit instead of using this bolt meathod.
Now my question is, can the insides of the disconnect be purchased seperately? I may want to convert the gears to the awd unit instead of using this bolt meathod.