How to test an awd front diff

[Camarokidz28]

So I purchased an 05 rainier with 140k miles 5.3 AWD. During my test drive it drove great, nice and quiet. Being AWD I don't know of a way to test that aside from flooring it in dirt. Well it rained yesterday and on the wet roads I'm sliding around like a mad man.

So to my question. After some digging I decided to start testing. Jacked up all 4 wheels of the ground. Awd engages front driveshaft spins and the wheels do not. Now my understanding is that there is no disconnect on the AWD models. Spinning the driveshaft by hand causes nothing to happen and spinning the driver's wheel causes nothing to happen. Does this mean it's a bad front diff? When driving the thing is quiet as can be. No unusual noises that would lead me to thinking it has a bad diff. If there is something I'm missing please let me know. And if it is diff can I use any front 3.73 diff? Or is it awd specific?
Thanks in advance

 

[Mooseman]

Sounds like the intermediate shaft is stripped.
https://gmtnation.com/forums/thread...diate-bearing-assembly-or-differential.19240/

 

[Camarokidz28]

So with a stripped intermediate shaft the driveshaft will spin freely without turning any of the wheels in the slightest? I'm also not experiencing any of the noises that he's speaking of

 

[TollKeeper]

That is correct. with no teeth left on the shaft, the power will follow the past of least resistance, which is the shaft with stripped teeth.

 

[Camarokidz28]

Well I was gonna wait until tomorrow to look. But it was driving me insane. So I pulled it apart tonight. Only took about an hour. And I'd say a good 20 minutes was on the top bolt. Had my girlfriend check while I spun the driveshaft and she said the shaft was indeed spinning. So I'll have to get the replacement parts. You guys are awesome!
Any reason why it only used about 1/3 of the spline shaft?

 

[TollKeeper]

Be glad your Full Time disconnect plate came off in one piece. But at least now you know what the problem is.

 

[Camarokidz28]

Be glad your Full Time disconnect plate came off in one piece. But at least now you know what the problem is.

It actually came off really easy. I didn't have to pry anything. The intermediate shaft came out with the disconnect. I didn't have to pull anything. I am concerned that it appears to be barely inserted in the disconnect

 

[Mooseman]

Unless the shaft was stuck to the disconnect, it should have stayed in the differential and would have needed a bit of force to get it out, either a slide hammer or some prying. And you're right, it looks like the splines were not fully into the disconnect like the stripping seen in the other thread I linked. Either the shaft was in too deep into the differential or the disconnect was not fully bolted in or it was damaged internally and the splines were not fully engaged.

What does the other end of the shaft look like? Please post a pic of it to compare.

 

[Camarokidz28]

The entire job went very easy. The disconnect was jiggling while I was taking off the 3rd bolt. I can insert it until it bottoms out. I can remove it by hand with no resistance.
I don't see anything that would lock this in place. There is no groove or spring or anything. What is supposed to hold it in place?
I'm assuming that this has already been done on mine considering how difficult other people make it sound.

 

[Mooseman]

I always thought there was a C-clip but I guess not. Could be held in just by friction or some sort of clip in the diff. When you get all the new parts, test fit everything before bolting them in to see if the splines engage deeper than the last one. If they don't, it will likely fail again. The bolt bosses on the disconnect should bottom onto the pan bolt hole bosses and the large part should be an interference fit into the hole in the pan. Clean out the hole and put antiseize to prevent problems in the future.

 

[Camarokidz28]

Yes I will definitely do that. What do I do if it does not engage any deeper? I'm not sure how to remedy that. I bought the kit from ebay that was posted in the other thread.

 

[Mooseman]

We'll cross that bridge when we get to it

 

[Camarokidz28]

We'll cross that bridge when we get to it

Well parts are expected to arrive by Saturday. I'll post back when I get them

 

[Camarokidz28]

Parts came in today. It does not appear to insert any further than the old one.

However I think I have found what I believe to be the answer. Clearly mine has been done once before given the ease of the job that I had. I'm guessing that whoever did this last time only changed the shaft and not the disconnect.
The new shaft inserts into the disconnect and then stops just before it seats to the oil pan and by tightening the bolts you are pressing the disconnect into the shaft by about 1/16". While inspecting the parts side by side I noticed the splines on the new disconnect started much closer to the edge which to me indicates it's been stripped out more than once.

Of course this is all speculation and I may be doing the job again in a few months lol. But for now the front wheels are spinning.
After I drive it a little I'll do a fluid change on the driveline. Anyone know what fluids I need for front diff, transfer case, and g80 rear?

Thanks, you guys have been immensely helpful

 

[Matt]

Transfer case is Auto track II. Summit sells it other than dealers. The front and rear diffs just take 75-90 gear oil, nothing special needed for the G80...don't put LSD fluid in it.

 

[Mooseman]

Amazon also sells the AT II fluid as well.
https://www.amazon.com/d/Power-Stee...8&qid=1546626002&sr=8-1&keywords=auto+trak+ii

 

[JayArr]

Hi Camaro

I think Mooseman is correct about the clip.

I had all of this out of my 05 Envoy a couple of months ago and mine had a clip on the shaft that went into the diff and your aftermarket one doesn't. In fact my shaft was so hard to pull out I had to put a bolt in the outboard end where there is a threaded hole and use a slide hammer to pop it out of the diff, I also had to pound on it with a rubber mallet to get it to pop back in. The manual tells you that the threaded hole in the outboard end was put there for that purpose. With the clip holding it in place in the diff I think it would fully engage in the disconnect but without any clips you've got a floating shaft.

I think your aftermarket eBay parts are going to fail.

 

[m.mcmillen]

I've had several out and have never seen a clip. I think the newest I've had one out of is a 2004 Rainier. I wonder if they updated it later on?

 

[Mooseman]

Just going from a long memory, mine I had to pull with a slide hammer too but I can't remember seeing a clip.

 

[Camarokidz28]

Hi Camaro

I think Mooseman is correct about the clip.

I had all of this out of my 05 Envoy a couple of months ago and mine had a clip on the shaft that went into the diff and your aftermarket one doesn't. In fact my shaft was so hard to pull out I had to put a bolt in the outboard end where there is a threaded hole and use a slide hammer to pop it out of the diff, I also had to pound on it with a rubber mallet to get it to pop back in. The manual tells you that the threaded hole in the outboard end was put there for that purpose. With the clip holding it in place in the diff I think it would fully engage in the disconnect but without any clips you've got a floating shaft.

I think your aftermarket eBay parts are going to fail.

I didn't see a channel for a clip on the one I removed or the one I installed. It did however install tightly. So I'm not sure what good a clip would do. It is working as of now. If it fails in the future I will be sure to post about it lol