What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Doubeleive]

Thats what I figure it is. Shop floor is all wet now and the Mrs needs me today.

unless you are snowed in you are good to go, lol

 

[George B]

unless you are snowed in you are good to go, lol

I has taken a-lot for me to learn that things like this are not critical. I used to get all balled up and would go to fixit mode. Now I can let it ride.

 

[gooffeyguy]

Now watch you get a bunch of snow in the next couple days!

 

[George B]

Now watch you get a bunch of snow in the next couple days!

Thats what drove the discovery.

 

[Doubeleive]

Thats what drove the discovery.

junkyard probably has one, just unplug the harness, grab a wrench and break it loose, then it just spins out, you might loose a couple ounces of fluid on the ground.
then you can either put the harness back on, hit the 4wd button and see if it works or not, or just apply 12v to the pins, sometimes they might barley move or move real slow. a good working one should move quick.

 

[Fless]

Found out my four wheel drive is inoperative. Front axle wont engage. Transfer case shifts into all modes and ranges.
When in 4HI and with one front wheel off the ground I can turn it. Drive shaft doesn’t turn so I suspect the actuator or shift fork mechanism. Checked with the tech2 and the truck believes all is well with no codes anywhere and everything seems to respond correctly.

Make sure the grounds that are on the frame, behind the driver front tire and below where the driver's foot would be are clean and good. One of those, I think, may be for the front actuator. You can also unscrew the actuator and let it hang down, and push your 4HI button to see if it extends. If it takes more than a second or so, or doesn't extend at all, you may need to test the circuit or replace the actuator.

EDIT: If you haven't yet, use the Tech 2 to command the 4x4 modes. Make sure that what's commanded, and indicated on the dash switch, is what the Tech 2 shows is actual. As an example, mine had an encoder motor that would light the switch in 4HI (as selected) but actual mode was AUTO.

 

[cmatt]

Got the wiring done so the C-shaped led acts as DRL only and also will come on with the park lamps. Just waiting on parts to convert the old drl bulb to a park/turn signal. Then need to decide to move forward with the led projector retrofit.

DRL

DRL + park lamps

 

[RooTBeeRthe1st]

Charged the batteries up since it's been sitting for weeks, getting started just long enough to move it from the street to the driveway and back a couple times.

Meanwhile I love truck has been taking up all of the driveway workspace and my time.
Might actually finish it today and be driving it tonight.

Then I will finally have a chance to start on the 14 bolt swap and see just what I killed in the 8.6".

 

[George B]

junkyard probably has one, just unplug the harness, grab a wrench and break it loose, then it just spins out, you might loose a couple ounces of fluid on the ground.
then you can either put the harness back on, hit the 4wd button and see if it works or not, or just apply 12v to the pins, sometimes they might barley move or move real slow. a good working one should move quick.

Make sure the grounds that are on the frame, behind the driver front tire and below where the driver's foot would be are clean and good. One of those, I think, may be for the front actuator. You can also unscrew the actuator and let it hang down, and push your 4HI button to see if it extends. If it takes more than a second or so, or doesn't extend at all, you may need to test the circuit or replace the actuator.

EDIT: If you haven't yet, use the Tech 2 to command the 4x4 modes. Make sure that what's commanded, and indicated on the dash switch, is what the Tech 2 shows is actual. As an example, mine had an encoder motor that would light the switch in 4HI (as selected) but actual mode was AUTO.

More clues…
There is a puddle of gear lube on the shop floor right under where the front axle actuator is.

 

[George B]

The right axle flange is pushed out of the housing. ???

 

[Doubeleive]

The right axle flange is pushed out of the housing. ???

HMM, well that's not right and would explain the fluid puddle, looks like it's been like that for a while has it been worked on by anyone? have you checked to see if it is full? i'm gonna guess it's not, if you remove the fill plug/bolt the fluid should be level with the hole

 

[George B]

HMM, well that's not right and would explain the fluid puddle, looks like it's been like that for a while has it been worked on by anyone? have you checked to see if it is full? i'm gonna guess it's not, if you remove the fill plug/bolt the fluid should be level with the hole

This is new. I was just under it less than a month ago doing the oil change. I inspected everything at that time. The diff is full and I check it regularly. The truck hasn’t leaked a drop since I have owned it. The front axle was out for service 40k ago by a dealer. I replaced that cv over a year ago. Thats all I know.

 

[Doubeleive]

I am not sure if you can unbolt the axle and then smack that back in with a deadblow or not or if you have to pull that housing off and put back in that way. all the rebuild videos show it just going back in easy with the housing when reassembled
on this video he shows at 25min just hitting the one side with a dead blow
im confused on which part it is at 27 min he shows the other side just getting pushed on

 

[George B]

I am not sure if you can unbolt the axle and then smack that back in with a deadblow or not or if you have to pull that housing off and put back in that way. all the rebuild videos show it just going back in easy with the housing when reassembled
edit I was looking at the wrong side
on this video he shows at 25min just hitting it with a dead blow

Yeah, I was just looking at this. It looks like there is a cir-clip that let go. I can try to knock it back but I might try getting that half off.

 

[George B]

I am not sure if you can unbolt the axle and then smack that back in with a deadblow or not or if you have to pull that housing off and put back in that way. all the rebuild videos show it just going back in easy with the housing when reassembled
on this video he shows at 25min just hitting the one side with a dead blow
im confused on which part it is at 27 min he shows the other side just getting pushed on

Based on this it looks like I will need to pull that side of the diff off. I wouldn’t trust that I git that clip right otherwise.

Rebuilding A GM 8.25 IFS Differential **56K Beware! Pic Heavy**

I am going to try to cover the basics on rebuilding the front differential in a GM truck with the 8.25" IFS differential. I am doing a gear change but also a full rebuild while I have it apart. Parts you'll need: Ring & Pinion Gear set, Master Install Kit, lock tabs (2)- (GM PN - 15588312)...

www.truckmodcentral.com

 

[Doubeleive]

Looks like the culprit right here, I bet you can just dead blow it back in and be fine

 

[Doubeleive]

what do you think @iamdub

 

[George B]

Looks like the culprit right here, I bet you can just dead blow it back in and be fine
View attachment 357234

I agree but am not sure if the clip is possibly broken.

 

[Doubeleive]

I agree but am not sure if the clip is possibly broken.

well, if it doesn't stay in then maybe..... I have heard of them just popping loose before

 

[89Suburban]

Holy mackerel.