Battery Ran Dead and now 4x4 does work

[jaydentruman]

My alternator and battery recently went on my 05 avalanche with the 5.3 4L80 and the Np246 and after the battery ran fully dead while I was driving my transfer case is not longer working. It threw a b0790 code. I thought everything just needed to reset so I pulled the battery terminal and checked all the fuses and everything looks good. I can’t figure out what is causing this. I fully rebuilt the transfer case this past summer so I believe it is something electrical. Does anyone have any ideas?

 

[jaydentruman]

I am thinking it is is the front diff actuator as I can hear the encoder motor switching the transfer case and it will gear down for 4 Low. I need to check my front driveshaft to see if it is being driven by the T-case. I will also get under and feel the actuator to see if I can feel it engaging. But any advice would be good

 

[Cadillacmak]

I work on a friends 04 Avalanche, but have not run into this problem. I did find that his radio was running his battery dead as it was getting really hot even with the key off.

Also if you get a chance, post a picture of your truck and introduce yourself here. https://www.gmt800.com/forums/introduction.3/

 

[jaydentruman]

Ok sweet!
Yeah my alternator went bad and we are going through a cold snap of (-30-40 C) so already put a new battery and alternator and fixed that problem but now my 4x4 isn't working lol.

 

[ORVietVet]

Have you pulled the transfer case switch and inspected? Checked the grounds for that circuit?

 

[jaydentruman]

I haven't had a problem with the switch so far but it could have been due ti the bad alternator. I will clean those grounds up tonight and let you know if that is the issue. My switch is still engaging the 4 low switch of the gearing so I think it is ok but I will double check. Thank you!

 

[jaydentruman]

Ok so I have gotten underneath the truck and I can hear the encoder motor switching and it will successfully put the truck into low gearing. I can feel the actuator on the front differential moving as well. I don’t know if it’s going enough but when four wheel drive is selected it moves or at least tries. So I am assuming my ground and switches are ok. Does anyone have any more suggestions?

I am going to put the truck on jack stands tomorrow and see if the front wheels/ driveshaft turn when trying to drive. It displays the same symptoms as when the clutches in the t case went but I don’t think that’s the case cause it was replaced 6 months ago with brand new clutches

 

[jaydentruman]

Could the actuator still move but just not fully engage the front differential?

 

[ORVietVet]

Could the actuator still move but just not fully engage the front differential?

I would ASSUME so but unsure. When up on jack stands, make sure all 4 tires are in the air and out the stands under the front lower arms close to the lower ball joints and under the axle tubes. Do not put them all on the frame and let it all hang. When set the stands at the front and let weight down on the stands, make sure you jounce the front, side to side to verify is sturdy.

 

[jaydentruman]

For sure! Me and my buddy were talking about it and we are wondering if the plastic internals of the actuator stripped as it is very cold here the last few days -35 C or -31 F

 

[ORVietVet]

When you get it all set up, please take pics of the set up, diagnostics and repair and post here, with your write up. Thanks.

 

[jaydentruman]

Update:

I got home today and began to tear into the truck. I cleaned the grounds up, they were already looking pretty decent but I cleaned them up anyways. I then took my actuator off and it looked decent. there is no wear that I can see, I cleaned it up and re installed it. I forgot to test it with it out of the diff (will do that this evening). I tried the 4x4 and still nothing and no warning lights.

I have it on jack stands and am going to look at everything with it running in the air. I am running out of possible issues as everything in the transfer case was replaced this past summer so I am unsure.

I will post another update this evening after I test everything. Just had a bite to eat and am going to keep working.

 

[jaydentruman]

Final Update:

Looks like my nightmare came true. Clutches are burnt out again. Fluid is burnt and front wheels spin on the jack stands but I can stop them with my hand. I am unsure why they burnt out so fast as I don't use 4 auto ever out of fear of burning the clutches (how ironic) and never use 4 high at highway speeds.

I am wondering if something was missed when we rebuilt it this summer. Or if there wasn't enough pressure on the clutches and caused them to burn? I am unsure.

What I am sure of is that I either need to throw a new transfer case at this ole girl or at the minimum a new clutch pack. Thanks for the help!

 

[ORVietVet]

I would bet you found your problem BUT, I would still look at that ground up the cable and under the insulation. Not just the connector. Not saying that is the problem but while you are in there, look at it.

 

[Cadillacmak]

Final Update:

Looks like my nightmare came true. Clutches are burnt out again. Fluid is burnt and front wheels spin on the jack stands but I can stop them with my hand. I am unsure why they burnt out so fast as I don't use 4 auto ever out of fear of burning the clutches (how ironic) and never use 4 high at highway speeds.

I am wondering if something was missed when we rebuilt it this summer. Or if there wasn't enough pressure on the clutches and caused them to burn? I am unsure.

What I am sure of is that I either need to throw a new transfer case at this ole girl or at the minimum a new clutch pack. Thanks for the help!

That is a bummer!

 

[jaydentruman]

Sorry for no more updates for the last week. It has been busy. I purchased a rebuilt transfer case with a WARRANTY and installed it mines in -25 C weather on the floor of my garage. It was a pain but I am happy to save the avalanche is back in business with a fresh transfer case as well as all the other potential issues checked and repaired lol. Here is a photo of my new transfer case I purchased as well as my truck hauling water for my acreage with the fresh transfer case!

I am hoping to post more updates with the build of my truck and fingers crossed no more hiccups. I am pulling some fender flares, mud flaps, and door handles from the scrap yard tomorrow to make everything look clean when we get some warmer weather up here!

 

[ORVietVet]

I could not work in cold like that, unless it was inside a heated garage.

 

[INW-Iron-Steel]

I am thinking it is is the front diff actuator as I can hear the encoder motor switching the transfer case and it will gear down for 4 Low. I need to check my front driveshaft to see if it is being driven by the T-case. I will also get under and feel the actuator to see if I can feel it engaging. But any advice would be good

Not helpful, but this is why I think GM should have just put the np261 in all the 1500s. Outside of pump rub issues, they are very reliable.

Sorry for no more updates for the last week. It has been busy. I purchased a rebuilt transfer case with a WARRANTY and installed it mines in -25 C weather on the floor of my garage. It was a pain but I am happy to save the avalanche is back in business with a fresh transfer case as well as all the other potential issues checked and repaired lol. Here is a photo of my new transfer case I purchased as well as my truck hauling water for my acreage with the fresh transfer case!

I am hoping to post more updates with the build of my truck and fingers crossed no more hiccups. I am pulling some fender flares, mud flaps, and door handles from the scrap yard tomorrow to make everything look clean when we get some warmer weather up here!

Sorry to hear you had to go the route of a new T-case after the rebuild. That is a huge bummer. Out of curiosity, what brand is that? The paintjob looks eerily similar to the 261 I slapped in my rig last year. Did it tell you to fill with motor oil opposed to ATF? And, did you do that?

 

[jaydentruman]

I am unsure the brand of the transfer case. I bought it from Western Powertrain in Edmonton. From the looks of it, it was just a core they rebuilt and slapped some primer on it.

Since the transfer case has the 4 auto system. You can only really use the GM autotrak fluid to prevent damage from what I have heard. Its like $16 at my local dealership so I figured i should just use that.

 

[ORVietVet]

I am unsure the brand of the transfer case. I bought it from Western Powertrain in Edmonton. From the looks of it, it was just a core they rebuilt and slapped some primer on it.

Since the transfer case has the 4 auto system. You can only really use the GM autotrak fluid to prevent damage from what I have heard. Its like $16 at my local dealership so I figured i should just use that.

Yea, you don't want to "good enough it" with that transfer case fluid. Get the GM recommended fluid.