Can I take an AWD front diff and combine it with a 4WD front diff?

[iregret]

If you have an AWD front end that has bad carrier bearings, can you take a wrecking yard 4WD front end and swap the longer axle and housing onto the 4WD?

[iregret]

Here's what I'm talking about. First a little backstory. I'm converting a 2000 regular cab short bed truck to all-wheel-drive with the long-term goal of a 700 hp turbocharged 6.0l. I've already got the 4L80E swapped as well as the NP149. I took my front end and locked it into 4HI and then disconnected everything.

 

I discovered that I had an oil leak. I crawled under the truck and realized that the long axle tube housing is cracked.

 

 

So I figured that I had two options. I could either find another 4WD front end and lock it into 4HI or I can find an AWD front and replace it. Supposedly the one piece axle from the AWD front end is stronger. How much? Who knows.

 

So I set out looking for a replacement front end. I looked on craigslist and at my local wrecking yards. I found a few on craigslist that were the 4 x 4 versions and people wanted around $350 or so for the front end. The wrecking yard? $1200.00! I was like WTF?!?

 

Luckily, I friend of a friend works at a GM dealership. I asked him to ask his friend if you knew where I could find any front ends. My truck has a 3.73 gear ratio.

 

He did.

 

 

So I ended up with two front ends. The one on the left is out of the 2005 Silverado and is a good runner. The one on the right is out of a 2004 Escalade and needs it's bearings replaced.

 

So my basic plan was to pull the long axle and housing off the AWD unit and swap it onto the 4WD unit.

 

Has this been done before? Can it be done?

 

I've read completely different responses. Some say yes, some say no. I'm not sure and I guess I'll find out. I think the earlier units you cannot do this on but hopefully the later ones you can.

 

I know I don't have an SS, but this information would apply to you guys as well. Except that you're going to have to find a 4.10 gear ratio for your front end.

[Downeast Johnny]

Hey Justin. Welcome to the site.

 

Sorry that I don't have answers to your question but wanted to say that your project sounds like a nice one.

 

Post up some pics?

 

Hope this bump helps get some more attention to your post.

[GI.SS]

I'm on my phone so I can't see that we'll, but the cases appear to be the same minus the actuator. If it were me I'd pull both shafts an measure width, length, and teeth count. If they're The same then money. It is a GM they will

Most likely I interchange

[iregret]

I wondered how the 4x4 actuator actually worked. So I took it apart.

 

 

It's a lot more complicated than I assumed.

 

 

The poor man's way of engaging 4WD without having the transfer case and all of the appropriate wiring still connected, would be to turn this until the actuator is fully extended.

 

 

Like so.

 

 

So I took the long axle and housing off of the AWD unit. I used a combination of a slide hammer and a dead blow hammer to pop the axle free.

 

You can see here there is a groove in the axle. There is a detent in the spider gear that locks it into place.

 

 

In case you were wondering how the 4x4 actually engaged. You can see how it pushes that fork over causing the fork to slide that collar over, joining the two axle halves.

 

 

This is looking down into the 4WD unit.

 

 

This is down into the AWD unit.

 

 

You can barely make it out, but there is a silver clip in there that snaps the long axle half into there.

 

So this means that it's not as simple as just unbolting the longer axle and tube, and then bolt that onto a 4WD front end.

 

For grins, I did see if it would fit, and it does. There's just no way for the longer axle to lock into place. The spline count is the same, and it's the correct length.

 

Now, I could bolt it in. The CV's would probably keep that front axle where it needs to be. What I'm going to do through, is just lock the 4WD unit into 4WD, then replace my cracked factory one.

 

In the coming months, I'll tear apart my AWD unit and rebuild it.

[iregret]

Here's my build up thread.

 

http://www.performancetrucks.net/forums/projects-gallery-189/2000-chevy-silverado-project-charlie-murphy-489579/

 

Nevermind the blog reference in the first post. I've pretty much abandoned it.

Edited June 28, 2013 by iregret (see edit history)

[iregret]

Here are both axle assemblies side by side. The overall length of the housing and axle are the same.

 

 

What I think I'm going to do is put the AWD one piece axle and housing onto the 4WD unit. I know there's a difference in the spider gears between the two. I've considered it, and I don't think it matters. After thinking about it, I think that the only reason there a detent holding in the AWD one piece axle is for the assembly plant. There's enough force from the CV joints to keep it in place.

 

I found out where my front end was leaking. LOL.

 

 

[Downeast Johnny]

It does look like that axle housing could leak a little bit.

 

Went through the first 8 pages of your build thread. Really enjoying the thread. Lots of pretty work going on there.

[iregret]

It does look like that axle housing could leak a little bit.

 

Went through the first 8 pages of your build thread. Really enjoying the thread. Lots of pretty work going on there.

Thanks man! i haven't really read the entire thing from beginning to end. I think I'll sit down and do that tonight. I learned most of my all-wheel-drive information from this website. I've been a long time lurker.

 

I cleaned off the mating surfaces really well with brake cleaner.

 

 

 

I applied some RTV black and put the two pieces together. Then I put the bolts on finger tight. Then I let it set up for about 20 to 30 minutes. Then I tightened everything down.

 

 

So now all I have to do is figure out how to get the center link to come free. I have to work tonight so I didn't have anymore time to mess with it.

[iregret]

I worked on my truck a little bit today. The first thing I did was pop out the old tie rods. I was having a problem getting the front differential to drop down. It's hanging up on the centerlink. It occurred to me that the reason that it wouldn't drop down was because I installed lowering spindles. The lowering spindles compromise my turning radius.

 

Earlier I had tried removing the tie rods with a pickle fork. I ended up destroying the boot. I actually have a tie rod puller. The problem was, the factory tie rods were too long. So I went to AutoZone and ordered replacements. When I got home I cut the factory tie rods down and broke them free with the puller. I wish I would have just done this in the first place. Now I have to measure and try to get my alignment right.

 

Once I got the tie rods free of the spindles sure enough, I could turn the steering wheel all the way to the left and get the front differential to come out.

 

With the factory differential finally removed I turned to my newly modified AWD/4WD front diff.

 

I removed the factory black vent so that I could inspect the gearset inside the differential.

 

 

 

Since I have the front diff out and everything I went ahead and replaced the black vent with the newer white vent. Supposedly there were problems with the black vent backing out and being incompatible with synthetic gear oil. Looking at both of them side-by-side the only difference I can tell is that the newer one (white) has a metal breather instead of a plastic one.

 

After that I filled it up with approximately 1.5 L of Mobile1 75/90 weight synthetic gear oil.

 

 

Then I bench-pressed this into place.

 

 

Now all I've got left to do is to button everything up and torque everything down. Oh yeah, I have to replace the tie rods too.

[Joe Roknic]

I love this site....a guy comes on the site looking for help, ends up doing a detaled how to... welcome abaord and thanks for posting all the photos

[iregret]

I love this site....a guy comes on the site looking for help, ends up doing a detaled how to... welcome abaord and thanks for posting all the photos

Thanks man! I love writing how to's. Hopefully it helps some one.

 

The first thing I did today was clean up this piece.

 

 

This part goes under the oil pan. It was full if gunk and build up oil. You basically fill it with oil every time you perform an oil change. LOL. I scrubbed it down with a wire brush, a screw driver, paper towels and brake cleaner.

 

Then I moved on to the tie rods. I don't want to pay for an alignment, so I did some measuring.

 

So the replacement tie rods from autozone are slightly different. So to get it as close to where it was as possible, I measured the length from the grease zerk. I needed to get as close to the center of the tie rod as possible.

 

The factory piece measured 119.8mm.

 

The autozone piece measured 124.9.

 

A difference of 5.1mm.

 

Before I removed the factory tie rod end, I loosened the nut, then hand tightened it back to where it was. This gave me a reference as to where the factory tie rod was located.

 

 

I put the replacement tie rod on and tightened it to the nut. Then I moved the nut 5.1mm farther in.

 

 

After that, I screwed the tie rod in to meet the nut at the new location. I tightened everything down. Now, I'm within 1/16 of an inch from where the original tie rods were.

 

Then I greased all the steering parts and installed the pins in the castle nuts.

 

I also got the front diff installed and torqued down. As well as the front drive shaft and CV's.

 

I ran out if time with the 4th of July stuff going on, but I'm pretty close to finishing up.

[Downeast Johnny]

Nice "step by step" and photos Justin. Just the kind of thing the site can use more of.

 

I'm looking forward to your future post's.

[iregret]

Well, I buttoned everything up and went for a test drive. It drives better than ever. Previously, there was a mild vibration. That went completely away. Awesome!

 

Now there's a new problem. The air conditioning isn't working. I looked at it for a few minutes and it doesn't appear that the A/C clutch is engaging. The light turns on in the cab though.

 

I'm wondering what I did. Did I screw something up in the tune? Did I screw something up when I added the electric fans? Is there a problem in the ECU after I added the pins for the 80E? Is the refrigerant pressure low?

 

Ugh. Where to start. LOL.

 

Here's a dirty pic of my truck. Repaired! (Sort of. LOL)

 

[Bobs SSR]

Iregret how did the swap over worked our, any problems with the clip missing? I have awd and was thinking purchasing a 4wd diff since it might have had less wear than a awd case.

Edited August 22, 2020 by Bobs SSR (see edit history)