4wd not working *solved*

nuddybuddy · Post by **nuddybuddy** » Tue Dec 27, 2005 3:45 pm

hello, I a newbie to this site.

I bought a rebuilder 2004 cc gmc sonoma 14,000 miles I have been working on. I been testing the 4wd to pull into my garage (on an incline w/gravel 4wd works fine in both hi an lo.

Today I drove down a 10 foot incline. When I was coming out the truck spun. I kicked it in 4hi and drove up the incline about a foot and I heard a loud clank noise like it popped out or something. I only had 2wd. I put it in 4lo and nothing. I can hear it changing over when I hit 4hi and 4lo but I have no 4wd. the vaccum thing goes up when I engage it.

all help and info greatly app.

Post by **Walt** » Wed Dec 28, 2005 11:15 am

I'm no expert here, but the clank you heard is probably the locker in the rear diff engaging if your truck is equipped with one (check for the G80 code in the glovebox). Your 4wd problem might not have anything to do with the clank.

The reason I say that is because if you truck is equipped with the factory Eaton locker, one wheel will spin for a sec, and the locker will engage, but if the wheel is moving more than 2 or 3 mph, the locker will make a loud clanking noise once when the other wheel engages.

Also, try totally disconnecting your battery for 10 minutes or so and see if that helps.

Just a thought. Maybe some of the more technically astute members on here can troubleshoot further....

nuddybuddy · Post by **nuddybuddy** » Wed Dec 28, 2005 12:25 pm

I disconnected the positve side for 1/2hr. rehooked it up and tried the 4wd out and nothing.

killian96ss · Post by **killian96ss** » Wed Dec 28, 2005 12:42 pm

Try reading this. Transfercase Codes Your problem sounds like the encoder motor, but try this diagnostic that HenryJ recently posted. This is good information and should help you track down the problem, but if you still can't figure it out let us know and we may be able to help you further.

Steve

nuddybuddy · Post by **nuddybuddy** » Thu Dec 29, 2005 10:17 am

I tried the code out , it only blinks once. so I pulled the fuse for 1 hr put it back in turned the key on and off 5 times , then tried the 4wd out and nothing. any other suggestions.

killian96ss · Post by **killian96ss** » Thu Dec 29, 2005 9:13 pm

It still sounds like the encoder motor to me. Do you have a local GM dealership? You can have them diagnose the exact cause of the problem, and then fix it yourself to save some money. I'm surprised nobody else is giving their opinion about your problem.

Anyone else have any ideas other than going to a dealership? If your problem does turn out to be the encoder motor or transfer case control module then you might like to know that neither one is very hard to replace.

Steve

killian96ss · Post by **killian96ss** » Thu Dec 29, 2005 9:21 pm

nuddybuddy, I meant to say this earlier! Welcome to the forum!

Steve

F9K9 · Post by **F9K9** » Thu Dec 29, 2005 9:26 pm

killian96ss wrote:It still sounds like the encoder motor to me..........Anyone else have any ideas other than going to a dealership? ........Steve

Steve, I knew about HJ's original source for the link that you provided and have tried my best to interpret his "single flash" but am unable to provide a better suggestion than what you have already provided.

Post by **HenryJ** » Fri Dec 30, 2005 7:59 am

I'd like to help here , but there are just way too many variables on a "builder". Without looking I have no idea what has been replaced, damaged, might be missing or incorrectly assembled.

The best I can offer is this link to the S-series.org - Understanding Your Front Differential

From what you describe, you have checked the actuator to make sure it is moving the cable. Next would be to make sure the actuator is moving the shift fork by disassembling it at the front axle. The shift fork is spring loaded and should move easily.

Sorry that I can't be of much help.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 8:58 am

can you give me a quick step by step on where to disassemble it at the front axle. not sure where I should take it apart ??? is it at the tube and the carrier case.

when I switched frames over the pass. axle fell out and I had to take it apart at the housing because of the washer slipped. I put it back togehter just like those pics. does it matter which way the sleeve goes on?

Post by **HenryJ** » Fri Dec 30, 2005 9:18 am

nuddybuddy wrote:can you give me a quick step by step on where to disassemble it at the front axle. not sure where I should take it apart ??? is it at the tube and the carrier case.

when I switched frames over the pass. axle fell out and I had to take it apart at the housing because of the washer slipped. I put it back togehter just like those pics. does it matter which way the sleeve goes on?

I think you may have found your problem. Yes it does matter which way the sleeve goes in.
You will need to remove the front differential assembly. Stand it up on end , resting on the drivers side short axle. Pull the passenger side (long) axle and the tube.

If the front axle won't engage it is likely that the washer is not centered. It may have again dropped out of position when you last assembled it. If the shift collar/sleve is installed backward I would think that it would not disengage? I could be wrong though. Look things over carefully when you have it apart. It should be pretty easy to figure out which way it needs to go in to work properly.

killian96ss · Post by **killian96ss** » Fri Dec 30, 2005 9:21 am

Are you sure the t-case is engaging? If you put the truck up on jack stands with all 4 wheels off the ground and engage the 4wd does the front driveshaft spin? Make sure this is not your problem before you start tearing the front diff apart. When my encoder motor failed the front diff would still engage, but without the t-case engaged you will still only have 2wd. maybe you have already checked this, but I just wanted to be sure.

Steve

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 9:33 am

henryj whenever I pulled my truck into my garage it is on a good slope w/gravel. I have the bed off and the back end is very light and it will just spin the tires I would put it in 4hi and it would pull up just fine. it did disengage fine when it did work.
I will go out and jack all 4 wheels off the ground and see what happens.

Post by **HenryJ** » Fri Dec 30, 2005 9:48 am

nuddybuddy wrote:... I have the bed off and the back end is very light and it will just spin the tires I would put it in 4hi and it would pull up just fine. it did disengage fine when it did work.

So does it work or not?

nuddybuddy wrote:...I kicked it in 4hi and drove up the incline about a foot and I heard a loud clank noise like it popped out or something. I only had 2wd. I put it in 4lo and nothing. I can hear it changing over when I hit 4hi and 4lo but I have no 4wd...

This is what I was trying to help with.

HenryJ wrote:I'd like to help here , but there are just way too many variables on a "builder". Without looking I have no idea what has been replaced, damaged, might be missing or incorrectly assembled.

Sorry.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 9:55 am

no 4wd doen't work. all help is more than greatley helpful. I am trying everything you guys are telling me and directing me.

I just jacked all 4 wheels off the ground and the front drive shaft does spin. I grabbed the drive shaft to see if I could hold it still and it still spun. should I take it apart and see if the fork is engaging?

Post by **HenryJ** » Fri Dec 30, 2005 10:04 am

I would take the actuator off first. Pull the three bolts, pry loose the retention spring and take the cable loose. You should be able to feel if the shift fork is moving properly. Rotate the RH wheel to see if it sleve engages it. If it does not, you will need to pull the diff. and check that washer and sleeve.
Pulling the front diff. is really not all that bad a job. I swapped a Tahoe diff twice a few weeks ago.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 10:18 am

I pull the 3 bolts on the shaf housing correct? when I pull the acutator off pull loose the cable then take off the retension spring?

when i pull the actuator off there is a short shaft that has the retention spring (kinda like a coiled spring)??

do I push the shaft in and rotate the RH wheel?

Post by **HenryJ** » Fri Dec 30, 2005 10:26 am

Yes the shift actuator. If it won't go in all the way , then it is likely that the washer has dropped down preventing the sleeve from engaging the differential side gear.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 10:32 am

how much play should that have, when I push it in and out?

Post by **HenryJ** » Fri Dec 30, 2005 10:34 am

It will travel nearly an inch. That is not important though. You want to make sure it engages. If it does slide and engage the axle then your problem is elsewhere.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 10:53 am

I will be getting to it later this afternoon. I will keep you posted.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 11:59 am

I pulled the acutator off the tubing and the cable. pulled the pin out while turning the passenger wheel. I saw the front driveshaft spinning. So then I kept the pin pulled out and turned the driveshaft and the tires moved. (oppisite directions) so does that mean I have a bad cable? when I put it in 4wd the acutaor crunches together. how do I tell if I have weak vaccum?

I'm going put in 4wd pull hose off actuator and see how much vaccum there is.

Post by **HenryJ** » Fri Dec 30, 2005 12:14 pm

Sounds like you are taking the right approach. Try attaching a hose to the actuator and pulling vacuum on it. If you suck on it it should not leak back. If it does the diaphram is bad.
A hand vacuum pump would be nice to check this, but do what you can. Make sure you don't have any vacuum leaks and that the switch on the transfercase is providing vacuum to the actuator.

If you have engaged the front axle manually and the tires spin then you just need to find the problem by following the components back from the front axle.

I do not know exactly how much vacuum is required to operate the actuator. I would imagine 10lbs would be enough. I doubt the system provides much more than 20 lbs or so, depending upon your altitude.

How much damage was there to the left front fender? Any chance the vacuum reservoir inside it was damaged?

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 1:36 pm

I just pulled the vaccum hose of and found out the the screws on the bottom of the vaccum actuator are gone. I put new ones in, tried 4wd and still not working. I think the cable is not pulling the pin out so 4wd will engage.

Post by **HenryJ** » Fri Dec 30, 2005 1:40 pm

If you put a hose on the actuator and suck on it does it try to move the cable?

If it does the next thing to do is check that hose to see if it gets vacuum when 4x4 is engaged.

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 1:58 pm

when I have the hose off and 4wd button is pushed it does have a suction vaccum i'll. I'll hook a hose up to actuator and see if it tries to move.

Post by **HenryJ** » Fri Dec 30, 2005 2:03 pm

Since it does have vacuum to that line when you switch to 4x4, the problem must be between there and the axle.

Bad cable? Bad actuator diaphram?

killian96ss · Post by **killian96ss** » Fri Dec 30, 2005 2:26 pm

Maybe the cable is seized up and needs some lube.

I remember seeing this before on ZR2.com.

Steve

nuddybuddy · Post by **nuddybuddy** » Fri Dec 30, 2005 3:38 pm

I got it fixed thanks to all the help and tracking things down from you guys. it was the vaccum actuator, the screws came out of it and it did not have pull on the cable. when I took it apart and put it back together to try it out again I did not get the cable locked into the spring. now it is working great.

thank you all for replying, and giving me all the info. I've been looking for those pic diagrams forever. thanks guys HenryJ thank you.

I will definatley be back I only had my truck for 2 mo. it is a rebuilder and I been working on it slowly. it has come a long way. it is a 04' 14,000 miles.

Happy new year!

F9K9 · Post by **F9K9** » Fri Dec 30, 2005 4:00 pm

Glad that they could help you. Rebuilder is not a term that is it used in my part of the country. Is it used to describe one who takes an insurance "totalled" vehicle and uses other parts to make it road worthy? We call the finished product "clips" here and KY will license these type of vehicles.

Post by **HenryJ** » Fri Dec 30, 2005 7:12 pm

Thank goodness your trouble shooting skills are in good standing!
I was not of much help since I tend to go worst case scenario

Fortunately you were able to solve your problem

Taking on a totaled truck is quite a bit of work, but well worth the efforts on a good one.

I used to work for a guy who rebuilt salvage vehicles in the off season. It was lots of fun.

Thanks for taking all the suggestions with a great attitude. It really can be frustrating to try to diagnose a situation with so many variables.

S-10CREWCAB.NET

4wd not working solved

4wd not working solved