2003 CDL Install Confusion

donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
I have read every forum post I can find about installing a CDL and linkage into a 2003 t-case. I even resurrected this old PDF that's mentioned everywhere but results in a dead link (thanks Wayback Machine). I attached the document for reference.

Here's what I'm working with. I have a 2003 Disco with only 67k miles on it. I also have a 2004 Disco parts truck with nearly 200k miles. I would like to retain as much of my 2003 t-case (low miles) as possible.

All of the forum threads I read, and that PDF document, mention taking the front housing and the front gear set out of the CDL equipped t-case and swapping them into a 2003.

But, isn't just the front housing what needs to be swapped and not the gears inside? My understanding is that the missing component is the linkage for the CDL and that's what is in this 2004 housing but not the 2003.

So, do I need just the 2004 housing swap, or the housing and the whole front diff/gearset as well?

Also, has anyone done this without removing the Y pipe. I would love to avoid that.
 

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jprover2

Well-known member
Apr 8, 2017
146
10
Birmingham,Al
The front housing is what locks the center diff. You are correct.

But you could pull the t-case and shifter/cables from the 04' and install them in the 03'. Unless the 2004 has been ran without gear oil, it's good to go. You may want to drain the fluid and pull the inspection plate on the 04' t-case and make sure there's no discoloration on the gears or large flakes on the drain plug. Gear driven transfer cases are tough and honestly high miles would not concern me. You will need to drop the y-pipe to do this.

If you do swap the front of the 04' onto the 03' then pull the center diff apart and swap in a one piece cross pin, if you're going to swap the front why not beef it up. Either way dropping the y-pipe will make this job easier. Here's a vid.

 
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donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
Thanks for the suggestion. Although you're probably right about just swapping the whole case and not worrying about it, I really like the idea of not dropping out 2 t-cases and just working on the nose cones.

Funny thing, I just watched that video today and might just order that cross pin while I'm at it. If you notice in the video, at about the 1:58 mark, the housing comes off and the internals are left in the case.

Is that all that's needed for the swap? Just the housing and not the gearset? So, I'm keeping the gearset from the 2003 in the 2003 or am I swapping that whole gearset from the 2004 into the 2003?
 
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jprover2

Well-known member
Apr 8, 2017
146
10
Birmingham,Al
The gears are left alone, only the front is changed. If swapping the cross pin, the detent has to be removed. This is the plug/spring/ball that is removed on the upper edge/ passenger side of the t-case. You'll have the console out to swap the shifter and cut out the hole for shifter movement when locked. I would leave the console out when modifying the t-case, you could have helping hands above to reach through the shifter hole to assist. Reaching through this hole to assist, or connect cdl linkage will leave you skinned and scarred but thats part of the fun.
 

donniefitz2

Well-known member
Sep 15, 2020
138
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Scottsdale, AZ
fitzventure.com
The gears are left alone, only the front is changed.
Thank you! This is the one thing that no forum post or instructional PDF mentions. So I keep all of my 2003 gears and just use the 2004 housing (which has the CDL linkage bits). Awesome.

I'm not too worried about the linkage. I know it'll be a PITA but I have all the parts from the '04 so that's good.
 

donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
Okay, I'm knee deep into this CDL procedure. I'm trying to get the front housing off of my 2004 donor. I got the housing loose, everything is unbolted and disconnected. The problem is, the housing is up against the transmission. This causes it to be at a crazy angle making it near impossible to pull off.

I haven't seen any forum posts about this being and problem. Most people say removing this housing is easy. I must be missing something.

I attached some picks to show what I mean. Anyone have any suggestions?
 

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donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
The Y pipe really isn't in the way yet. At least, that's not what's preventing the housing from moving forward. It's just up against the transmission. I think the Y pipe will be the next problem and I'll pull it, but the transmission is what's really in the way here. It's really bound up.
 

donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
I got my CDL in. It's really hard to find a straight story on how this process works. Because of this, I decided to make a YouTube video about the whole process. My video is 2 parts, but the 2nd part is the only one that matters. It can be found below. And, I am no video making pro so this is an amateur production.

 
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Blue

Well-known member
Mar 26, 2004
10,043
856
AZ
Nicely done, Don!

Interesting about that bearing coming apart. I never had any problems or noises with my diff lock.
 

sdtim

Active member
Feb 21, 2021
31
11
Oceanside, CA
First off...donniefitz2, thank you so much for including a copy of the instructions and the amazing video. I've already watched it several times.

I have a 2004 transfer case that will be the nose cone donor for my 2003. Do you have any tricks / recommendations for getting the gears and spline to line up on the install? I spent a few minutes practicing with the 2004 TC and wasn't able to get the cone to fully seat...it stops short by ~1/8".
 

donniefitz2

Well-known member
Sep 15, 2020
138
56
Scottsdale, AZ
fitzventure.com
That was a tricky thing to do. I had it in a similar spot, about an 8th of an inch short (open for jokes). I just wiggled it and messed with it and eventually it went the rest of the way. I think I put the t-case in neutral and worked the front drive shaft a bit to align the gears.
 
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