No 4wd at all, but i can hear both actuators

[Mirror]

My 4x4 switch seems to be working fine. I can hear the actuator motor running when switching between settings but it's not locking into a4d, 4hi or 4lo. Do i need a new transfer case? Absolutely no dash lights for 4x4. Only an abs light.

Was out today and checked some more. I turned the engine on and shut off the radio and blower so i could hear. I put the truck in neutral and took my foot off the brake then switched from 2wd to 4lo, heard the same noises then felt the truck jerk forward a tiny bit. Did this from 2wd to 4hi as well. But when i put it in drive and push the gas pedal fast, the rear tires spin and the front tires just roll normally with no extra power.

 

[IllogicTC]

How many miles? Was the transfer case fluid drained and refilled with Auto-Trac II (blue fluid from GM) every 50k miles?

Also, try the easy flowchart located here at GMTNation's sister site, OffroadTB. Gives you all the instructions on how to check various parts.

After you can single out specifically which part of the system is giving you trouble, we can go from there.

 

[Mirror]

I just got the truck in november so I have no idea when the fluids were changed or what is in it. it has 140,753kms on it.

 

[RayVoy]

Without doing any testing, it sounds like the passenger side front axle disconnect is broken. A very common problem. Try a search and read some of the threads, see if it sounds like yours. There will as be some testing you can try.

 

[Mirror]

i did just change both hub/bearings on the front and now there is a vibrating sound on the passenger side. when i turn right it's louder and when i slow down.

 

[linneje]

It would be easier for the members if you completed your profile of your vehicle ... if you listed the year model and engine in your profile it would help.

Does your switch light up the correct setting (4WD) when you select it? Or does the 2WD light stay lit?

 

[IllogicTC]

i did just change both hub/bearings on the front and now there is a vibrating sound on the passenger side. when i turn right it's louder and when i slow down.

I don't believe the 4x4 system would involve the hubs, however that sounds like one of the hubs might be bad out of the box to me. But why it sounds from the passenger side but gets louder turning right is beyond me, usually right means driver side, left means passenger.

A garbage hub could also be the issue with your ABS light, by the way.

 

[Mirror]

switch works fine

 

[linneje]

I agree with RayVoy, it sounds like your disconnect is broken, which is a gear carrier attached to your front passenger half axle. In 2WD, the two half axles from each side of the front are not joined or locked. When you choose 4WD, A4WD, or 4LO an actuator is signaled to extend a plunger. If this plunger extends properly, the switch will light up properly. (Occasionally the plunger is the problem)

The problem is, when parts in that carrier get worn or broken, the two half axles will not lock together even though the plunger is pushing correctly. And so you will not have 4WD despite what the switch light is telling you. This can be diagnosed by jacking up the front of the vehicle (make sure the vehicle was in a four wheel drive mode when shut off) and turning the driver's front tire by hand. The passenger front wheel should turn in the opposite direction.

The ABS light is a different problem and could be a result of your hub change.

If this disconnect is broken the right front tire assembly will have to be removed to get the disconnect off and check it out by opening it up. Usually the parts can be replaced rather than replacing the whole carrier assembly. I had this problem and fixed it for less than $150 in parts - had I taken it to the dealer it would have been about $1600.

 

[linneje]

http://gmtnation.com/f79/4wd-not-functioning-correctly-9607/

Check out the thread above, as it has some pics and a great explanation of diagnosing the front disconnect.

 

[Mirror]

Well one good thing, the humming sound is gone. I put the truck in the garage and melted a lot of ice but not all. So there was ice causing the sound, since it started doing it both directions i turned.

 

[linneje]

Yes, in our Canadian climate that can happen. I have had really bad thumping from driving in snow/slush then having the vehicle sit for a couple hours - the amount of ice frozen underneath caused incredible noise.

On to fix your 4WD now.

 

[Mirror]

Ok well i lifted up the truck today and found out the abs light is caused by the speed sensor on driver side. The wire got cut somehow. Installed the original but now the light turns on and off. Could be faulty. As for the 4x4, the passenger side driveshaft is loose at the 4x4 disconnect. Guessing the bearings are shot. What is the kit part numbers so i can order new ones?

Holy crap, rock auto has the 4x4 disconnect for $470 and just tthe house for $430. So how do i get just the $40 worth of insides for it?

 

[IllogicTC]

Find someone with the part laying around and make an offer. Go to a junk heap or pull-a-part and ask about getting just the innards - the housing obviously commands a huge price in itself, so I bet they'd be willing to keep it if you didn't want it. Not sure why, because most of the gripes on here have been about the internals breaking, not the housing.

Doesn't seem to be any rebuild kits on the aftermarket. Summit's ATP disconnect specifically states in the description "You could buy internal replacement parts and housing--if available--at a big price, and then spend more of your time rebuilding, but why? ATP front axle disconnect assemblies eliminate the need for rebuilding..." what do they mean, but why? We want to do it, that's why! A single shift fork or something would cost considerably less than buying the whole thing.

 

[IllogicTC]

Actually I think I have something!DIFFERENTIAL CARRIER/FRONT AXLE | Nalley Buick GMC Brunswick

They have a whole exploded view there where you can identify which part you need and order it individually. For example, if it's the shift fork, you can net it for about $70 on there. Reading the compatibilities up top and comparing to the shop manual, this looks like our front axle, compatibilities listed on individual parts at the bottom of the page confirms part application for particular vehicles.

 

[Mirror]

So i would order parts 1 - 9 except 3 and 7 then?

 

[Mirror]

Well this sucks. I have to buy the entire 4wd disconnect. The front cover got worn out from the axel rotating in it cause everthing inside to get worn out or destroyed. Plus the back cover fused its self to where it bolts on.

Now we have to figure out how to get the rear bearing out. We sprayed some heavy duty rust inhibitor on it last night.

 

[Mirror]

Just phoned gm dealers and piston ring. No one has this in stock and their price us $900+tax

What year of trail blazers share this part? Or is it a different part number for different years?

 

[The_Roadie]

1) Read this link to get a FULL understanding of what's inside the unit: Offroadtb.com Front Axle 4WD Disconnect

2) And if you need a full assembly for a replacement, there's an aftermarket company making a MUCH more affordable unit: ATP 111001 (available on Ebay and Amazon typically)

http://gmtnation.com/f79/splined-disconnect-rebuild-replacement-info-8703/#post181037

ATP 111001 Front Axle Disconnect : Amazon.com : Automotive

For some nutty reason, this Amazon picture is for the AWD version with no provision to mount the actuator. I can't fix dumb.
View attachment 32543

 

[High Voltage]

Wow! What a great read! Bookmarked for future use.

 

[Chickenhawk]

Rock Auto also sells the ATP unit. Shipping is fast and relatively inexpensive to Canada.

 

[Mirror]

And it starts at $470 USD. Our dollar has dropped so that goes up a good amount. The amazon one after shipping and exchange rate will be $496 cdn before duty.

 

[Chickenhawk]

True enough! Amazon also now does prepaid customs clearing, duty (if any) and GST too so all that has to factor into the final delivered price.

I have dealt with both Amazon and Rock Auto in Canada, and both were reasonably quick. The only problem I ever had was two spark plugs packed into the wrong package from Rock Auto and they quickly offered to replace them or refund the price. I didn't bother as it was only $10 or so and it wasn't their fault anyway.

Amazon in Canada doesn't stock much in the way of auto parts but Amazon in U.S. is almost as fast and often cheaper. The only downside is that some items can't be shipped to Canada, but Amazon tells you right away as soon as you put it in your shopping cart.

Hope you are back up and running soon! We have to go for a beer after all! (Hopefully this also fixes the ABS code too, but if not, I will bring my code reader.)

 

[Mirror]

ABs code is the speed sensor. It fixed itself after i installed the old one back in since the new one's wires got severed somehow. But it didnt last long. Apparently there wasn't enough spacers on it. When we had the truck lifted in the air. We spun the driver side front tire forward. No problem. BUt when we spun it backwards, we heard a rubbing sound. Tracked it down to the speed sensor. The old hubs had about 7 spacers on it. Where the new hub only had two. They varied in size as well. I'm driving the truck right now with the disconnect off the truck. Luckily i only need it to drive 8 miles a day on a paved hwy until i save up the cash for a new disconnect.

 

[Mirror]

Here's a question, since i will be in need of an oil change soon. Can i access this stuck portion of the 4wd disconnect from inside if i drop the oil pan? Also how much oil do i need for an oil change?

 

[Matt]

Mirror, everything is in the owners manual, if you don't have one, download this: http://gmtnation.com/f23/need-service-manuals-get-them-here-371/

The 4.2 takes 7 quarts.

 

[The_Roadie]

Here's a question, since i will be in need of an oil change soon. Can i access this stuck portion of the 4wd disconnect from inside if i drop the oil pan? Also how much oil do i need for an oil change?

Dropping the oil pan is NEVER needed - hope you mean the oil pan skid shield?

The disconnect is on the side of the oil pan where the passenger side CV shaft goes in. You get at it from behind the wheel.

 

[BRomanJr]

1) Read this link to get a FULL understanding of what's inside the unit: Offroadtb.com Front Axle 4WD Disconnect

2) And if you need a full assembly for a replacement, there's an aftermarket company making a MUCH more affordable unit: ATP 111001 (available on Ebay and Amazon typically)

http://gmtnation.com/f79/splined-disconnect-rebuild-replacement-info-8703/#post181037

ATP 111001 Front Axle Disconnect : Amazon.com : Automotive

For some nutty reason, this Amazon picture is for the AWD version with no provision to mount the actuator. I can't fix dumb.
View attachment 19919

Isn't that picture of the backside that mounts toward the oil pan? Here are some other views.

 

[Mirror]

Dropping the oil pan is NEVER needed - hope you mean the oil pan skid shield?

The disconnect is on the side of the oil pan where the passenger side CV shaft goes in. You get at it from behind the wheel.

If you read the rest of the thread. The back plate broke off and the inner bearing is now stuck in the mounting hole.

That why i want to know if i can get access to it if i drop the oil pan. Not shield.

 

[The_Roadie]

My impression from reading about a few broken housings is that they can be tediously removed from the well that they're in by drilling holes in the housing and chiseling fragments out. Being careful to not nick the oil pan casting. Sorry I forgot what condition your issue was currently in.