Transfer Case Pump Rub - Kit Install

[Sammconn]

Well I said it was coming and here it is.

Nate, yes you told me so.

Ok, I waited too long. I've had the merchant pump upgrade kit for far longer than I'd like to admit. Three years.  :-X
I'm sitting at 331k kms, 210k miles.

Crawled under to grease before last trip out to city and seen oil on transfer case.
So I'm screwed, but need to go.
Checked oil a lot, but made the rounder.

So time to fix it.

[Sammconn]

So I was going to do this in the driveway, and something told me I shouldn't.
More than just the sub zero temps and snow.

I made arrangements to take it in to the service bay at work instead.

Partial tool list: ( I may be missing a few things, and off the top of my head )

Floor jack and jack stands (If you're lifted may not be needed)
11mm for drive shaft bolts
15mm socket and wrenches, gear wrenches, stubby is helpful if not needed
small screwdriver
drip pan
10mm socket for case bolts
12/13mm for one case bolt
17mm? for speed sensor
snap ring tools (big 90* ones worked best for bearing clip)
flat nosed snap ring pliers for bearing ring
small torx bit for pump
oil, cleaning supplies, and pump kit.

[Sammconn]

Jack up and support front end so you can get underneath comfortably to work.

Remove front and rear drive shafts.
This is where I had a problem, rear was the two minutes it should be, but the front...
Well the band clamp that's supposed to be on the output of the transfer case wasn't there.
Looked like as in never there... :-\

So I own a 210K+ truck, that sees a lot of gravel, dirt, and extreme temps.
The front drive shaft is "supposed" to slide in on the splines to disengage from the front diff.
Mine didn't. It was nearly seized.
Got free of front yoke, and about 1/2" out of transfer case when I realized there was trouble.
Now, I'm not at home, and my wheels are now disabled until this is fixed.

Enter WD-40, and others, and the "Swing Press".
Thankfully, I'd recruited a fellow Duramax owner, that also needs to do this to help.
We went to his toolbox (he's a machinist/millwright working at the same dam as me) and got his 1 1/2" brass drift (diameter), and a 4 pound hammer. Working the splines back and forth adding penetrating oils as we went, all of the sudden it wouldn't go back in. Now things get ugly. Can't drive truck like this, can't break anything as I am nowhere near parts, and I'm in the service bay at work. So a bigger 8 pound swing press joined us. Now if you've never operated a hammer on your back/side for an hour straight, I'll be the first to tell you that you're arms die somewhere prior to that. At this point we could see about 3/4" of the spline, and knew there was a lot more to go. I couldn't swing the hammer any more so we switched it up, and the fresh arms did the trick in another 20 minutes or so.

I have no pics of this, as the snow was melting fast by this point and we were in no frame of mind to take any.

With the drive shaft finally out, we could start to tackle the transfer case.
I started by disconnecting the 4x4 encoder and removing it from the case. Not necessary to remove, but recommended by several online sources to prevent breaking. Then disconnected the speed sensor, and removed the wiring harness from the transfer case and tucked it out of the way.

Drain the transfer case oil now or sooner. Not sure, but I suspect it could leak out if Murphy's around.

Next up is the case to trans nuts. You can see five of them, feel the sixth on top, and wonder how to get a wrench on the bottom one all at once. Starting with the easy ones, took the stud out of the case, (mud, dirt and time against me again).
Removed cross member bolts from trans, and lifted it up a big inch to gain access to the bottom nut. Was a real pain in the butt, but worked well. Once they are loose, you'll be scared by the impending 'flood' of trans fluid. Be not afraid, its only a few ounces as it turns out. With all the nuts off, or studs out, whichever occurs, the case is ready to remove.

It slides rearward, off of the trans output shaft, and then will want to fall on you. Not super heavy, 50-60 lbs, maybe, I'm a horrible guess at weight. once clear of the tranny, a couple rotations in a couple directions, and voila, it is out!



Here it is, on a cart, front drive shaft along for some remedial spline work.

[Sammconn]

I watched a few videos on YouTube about the removal and rebuild, and made life easier.

https://www.youtube.com/watch?v=8UrLzHnj4Pk

Hopefully the link works, this is the removal one. Yes it's a different case, but same principles.

From what I have read, it is necessary to do the work in this orientation for re-assembly reasons.
there is a fair bit of mass to the internals, and the must be properly aligned to get it back together.



Once you have it secure, remove the speed sensor, and the gazillion case halve bolts, noting the special ones locations.
Remove the rubber boot that covers the bearing retaining clip.



You can begin to split the case, as in get the halves separated prior to removing the clip. Once they are free, the big 90* snap ring pliers will get the retainer out of the bearing. The flat tipped ones I have would not open it far enough. There will be a noticeable clunk once the clip is free, and at that point you can remove the case half.



Here's the case split, bearing and pump already removed.

[Sammconn]

Here are the parts removed as well as the speed sensor.
The evil poorly engineered pump half is about to be replaced.

The bearing retaining ring, under the speed sensor, requires the flat tipped snap ring pliers to R&R.
You might be able to do it without, but it would be a bear I think.



Pump split in half.



And the new Merchant pump rub kit installed.

[Sammconn]

SO, my case had started to leak.



The little white line in the center on the nub, is light from above shining through.
(Read: I may be back here at some point if my fix fails)

So I chose this metal repair 'stuff' to hold things in.
There really are a lot of these products on the market, and I spent about a half hour making my choice.
Part of that process was, if it got worse before I got home whatever I had needed to work in less than ideal conditions, cold, wet, oily, dirty etc.



So with the case well cleaned, I worked this onto and into the case as best I could.

[Sammconn]

Case goes back together in the reverse order.
I used Loctite 515 flange sealant on the case halves for sealing.

The bearing clip is a bit tricky, and an extra set of hands made things a lot better.
You have to literally pick up the shaft about 3/8" while spreading the retainer and lining everything up.
Once it goes around the bearing it snaps in and you can finish up.

Bolt the case together and tighten in a criss-cross pattern. Re-install the speed sensor, and its ready to go.
If your studs came out like mine did, clean them and the nuts up with taps and dies, and put them back with some fresh Loctite.

We then spent about an hour cleaning up the splines, starting with wire wheels and brushes.
They didn't work, and eventually triangle files were the answer.

Cleaned and test fitted to make sure it would be GTG again for another 200K, and back in the truck it went.
Bolted it all up, reconnected wiring, refilled with oil.

Checked all options, 2 High, 4 High, and 4 Low. All worked, so it was back in business.

[Nate]

Nice job sam.

The 15mm stubby ratchet wrench works wonders on the top case bolt.

Did you keep it attached to the crossmember when removing or did you keep crossmember in place and work around it?

Hopefully your patch job holds untill you get a new/used half... ???

Did you refill with 5w30 full synthetic or did you go with oem fluid?

Also, did you go with the M.A. magnetic drain plug?



JR, kyle, tater (and others that have the 2007 OBS) - this is what happens when you wait way to long knowing this is a problem and can cost you a lot of money when it fails because you chose to wait..........

[Sammconn]

I left the cross member in place. Just took the bolts out to gain access.
Yeah, hoping the patch holds. Just wish I'd've had time to get one while I was out last time.
Oh well it will be a quick one next time. Lol.

I refilled with Dex 3 this time. Have an oil shortage somehow at home.
This one came OEM with the blue smurf juice that is normally in the 1/2 tons with the auto 4x4.
Not sure why, but that's what it had. I'll likely go to 5w30 when it's apart next time, but the blue oil lets you know where the problem is. Did not get the plug, and not sure they even had it when I bought the kit.

It was super clean inside, kind of shocking actually for the miles on it.
I am a little anal on fluid changes though, so that could be part of it too.

My buddy has the kit ordered now too. So it looks like I'll be giving him a hand soon too.

Guys, if you haven't done it, it's not that bad. As long as you don't have the front shaft issues I did it is likely a two or three hour job. And do it sooner than later. I got real lucky.

[Flyin6]

Sam,

I thought you had an LML, must have been mistaken

I understand the problem was rectified with latter LMM's and all LML's

[Sammconn]

Sam,

I thought you had an LML, must have been mistaken

I understand the problem was rectified with latter LMM's and all LML's

I believe that is correct. think it's the 2005ish to be later LMM's but not sure exact dates.
No I have the LBZ.

[Nate]

its basically all 4x4 models from GM from 98 to 07.

here is the link to MA that talks about the years that are effected.  https://www.merchant-automotive.com/p-4017-transfer-case-pump-upgrade-kit.aspx