TJ: Installing a 4-Speed Atlas

[Mike]

My TeraLow died.... Again.

Time for an upgrade! From what I hear, the best name in Transfer Cases is the Atlas by Advanced Adapters (AA). So, I went for the top of the line. The Atlas 4-speed. I chose the deepest gearing that they supply: 1:1, 1:2.73, 1:4.3, and 1:11.7.

Of course I was excited, but I quickly found that there was very little on line about how to install the four-speed. I found a few 2-speed installs and the Atlas website seemed to have several insights, so I felt confident as I unwrapped my new T/C:



What I discovered in the process of installation is that the 4-Speed is a little different than the 2-Speed. I am posting this installation in the hopes that other folks that are looking to install one might find this information helpful.

I made several mistakes during my installation that I will share. Since I was in a bit of a hurry, I really wish that someone had posted this for me to find before I had started.


Before starting anything, make sure that you got what you were expecting. Besides the shiny new Atlas, make sure that you got all of the installation kit:



And that you got all of the 4-speed shifter installation kit:



You will use everything that they send you. The only leftover parts are two nuts and washers that you take off of the 4-speed shift cable.

The real problem with installing an Atlas is that the instructions just plain suck (Sorry AA, I really like you folks but it is what it is). They provide you lots of good information, but it is scattered and out-of-order across manuals, so-called "step-by-step" instructions, and the AA website. I read all of them. If you are planning to install ANY Atlas you should too!

Then use them to create your own instructions (even so, there will be surprises along the way). This is what I did, and I am going to share my version with you of what I gathered from all of these:



I am not going to repeat all of the instructions that AA provides. The information that they provide is sound, but disjointed. My intent is to give an overview of the installation steps and some of the pitfalls that I experienced. So read the instructions carefully. Then, use this report as a guide as to the order of the steps and for the unusual things that you might encounter.

The first step of installation is to measure your original driveshaft lengths. Regardless of what you are running (and what AA might tell you), you need to enter into this installation with the knowledge that you will most likely have to change the length of one or both of your current drive shafts.

Step 2 is to measure your original clock angle. This did not turn out to be a major factor for me, but you may want to know this later on during your install, so take the time the time to do it before you regret it.

The instructions call for you to pre-assemble the shifters for the axles. I wasted a lot of time on this and did it wrong to boot. The only thing that I got close to right was that I put in the shifter base, the threaded rod, the DOM tube and Shifter housing on first:



Other than learning how the tube fits and that the threaded rod needed to be all the way in, this is a waste of time for installing a 4-speed in a TJ. The DOM tube has to be cut to fit with a 4-Speed. Something that the instructions will lead you to believe is incorrect. When mine didn't fit, it seemed obvious that the tube had to be cut, but I called AA to make sure.

BTW, the AA folks are super-friendly and for almost all things very knowledgeable about the install process while you are on the call, but they did need to do some research and call me back about an hour later to let me know that cutting was the correct answer.

Also, please note that the shifter body is installed incorrectly in the photo. It needs to be installed with the other side in the tube (as the manual shows, duh! - My bad!).

Preassemble the all-thread shift-link rods, but you should cut the heat-shrink tubing that is included into four equal parts and put two on each rod now. I'll show you why this is important later:



What you really need to focus on at this point is the assembly of the shifter handles. The handles need to be fitted as these photos show:





The only axle shifter-related things that should be installed on the actual case prior to installation are the shifter base and the brass yokes. Tighten the brass yokes all the way down and then back them off until they line up appropriately:



The next step is that the 4-speed shifter must be attached to the case prior to installation. The cable limits flexibility so preassembly makes sense. The shift handle is first assembled:



Note the shiny silver bolt at the base of the shifter that secures the cable's heim joint. This is the same thread pattern as the smaller black bolt that is used to secure the other end of the cable to the case. I got it wrong the first time. Save yourself a little time...

Use the black bolt to secure the other end to the case. Leave the jam nuts loose on both ends. It will make the positioning of the shift lever easier:



Now you will need to extract the old transfer case. Drain the oil from the original transfer case.

Remove the original transfer case. Besides removing the T/C, you will need to fully remove the shifter and all of its related components You will not need any of them with the Atlas:



For a stock shift application, this leaves holes in the tub that I wasn't happy about, so I used short bolts and washers to solve this problem:



Removing the original T/C gives you the chance to measure the distance of the front and rear output yokes from the point where it seats to the transmission. Measure these for both T/Cs and compare. This will indicate how much change to the drive shafts will be required.

You will also need to measure the original transmission output shaft and compare it to the Atlas transmission output shaft. The length has to be the same or less or you can have serious issues. Mine matched, so I pressed on.

Now that the original T/C is out, remove the 4WD light switch and the Speedometer switch to be re-used in the Atlas later.

The website instructions for the TJ include a note on sealing the transmission weep hole with RTV. Based on things that I found about this, it doesn't seem to be a critical step, but since AA recommended it, I stuffed some RTV in the hole:



The Atlas comes with a variety of clocking positions to choose from. AA recommends a 1" body lift to properly install the Atlas and I don't have that. Therefore, I was expecting problems.

As it turns out, the ProComp lift that I have has a mostly stock T/C position with a handy cross-member to hold up the transmission mount. Apparently, a stock position does not require modification to the tub if you can modify your belly skid. We will come back to the belly skid modification in a later post.

I was able to position the Atlas and mark a range of acceptable clocking positions with a Sharpie:



Remove the Atlas. Leave it on the transmission lift if you are using one. Insert the studs in the appropriate clock angle positions.

Important note! You really want to beg, borrow, or buy a transmission lift to do this! The 4-speed Atlas weighs 127 lbs DRY. A stock NP 231 only weighs 65 lbs dry. A transmission lift is a great tool for this job, so get one of these if you can:



Note that the studs are installed and the Sharpie marks are gone. A simple way to remove permanent marker on metal is to spray a small amount of WD40 on the marks and to rub it with a steel wool pad. The marks come right off in most cases.

You will need to remove the driver's seat, the stock console, and any carpet in the area of work inside the Jeep.

My tub did not need to be modified for the Atlas, but if yours does, now is the time to take a large hammer to the spots that are not working for you.

Without a doubt, the tub will need to be modified for the 4-speed shifter mount. I used an angle grinder with a thin cutting wheel to adjust the tub for the shifter frame:

[Mike]

The hole for the shifter rod to pass through was just a rectangular hole that I lined up using the top plate that AA provided:


Afterwards, I cut the carpet to fit the upper part of the shift boot and attached the full assembly:


Careful not to over tighten these three bolts. they are easy to strip. With the 4-Speed shifter in place, you can tighten the jam nuts for the cable.

Now put the Atlas into place for the final time and bolt it down to spec:



The 4-speed cable may want to lay on top of the Atlas. I wasn't comfortable with this so I secured the cable to the tub:


The original breather tube will need to be replaced with 3/8" fuel line. I did not have a breather fitting for the end, so I looped the tube up against the firewall and then down about 8 inches to prevent water or debris getting in. 5 feet of tube worked perfectly.

The Fill-Sight Tube, the 4WD shift sensor, and the Speedometer gear needs to be installed at this point. Note that the 4WD sensor goes into the driver's side hole. Both holes are fitted with a bolt when the Atlas arrives. I had to call to find out which one the sensor was supposed to be installed:


If you have the mechanical Speedometer like I do, you will want to replace the O-ring now. With the position being near the base of the case, my old O-ring leaks slightly. I plan to replace the O-ring when I drain the oil at the 500-mile break-in mark.

The electrical sensors will not have enough length to reach the new positions. You will need to add wire to each line and ensure that they match to their original points. The Atlas gets very hot, so you really should sheath the wires with something appropriate.

At this point, you should check the yoke nut torque specs on the Atlas. The instructions imply that they are not set from the factory, but I found that they were and that they had sealed them with RTV to ensure that they don't back out. Regardless, check them to make sure.

You are going to need to shift the Atlas to get the final positioning of the shifter housing. An Atlas is difficult, if not impossible, to shift without the gears turning, so you are going to want to fill the case with oil before you try. It has to be filled eventually, you might as well do it now.

It is completely is lost on me as to the best way to fill this case, but I can tell you what I did. I removed the top flange nut of the sight tube and forced my plastic pump tube over the nozzle fitting and pumped the oil in. You need to remove the factory plug on the upper breather before you do this or when you pump the oil it will come out of the open end of the site tube. Yep, learned this the hard way...

If anybody has a better way, please let me know!

Once the Atlas is secured and lubed, the axle shifters need to be installed. The all-thread for the DOM tube needs to be threaded into place. Run it all the way down by hand and then install the jam nut and tighten securely. Fit the shifter housing with the shift handles installed over the DOM tube all-thread (without the tube in place) and adjust to where the forward shift handle is about 1/2 inch from the tub when the T/C is in neutral. The case should have been shipped in the neutral position.


Measure the distance from the tube stop of the shifter base to the Shifter housing. This is the preliminary distance that you will cut the DOM tube down to. It will be too long, but it will let you set up for getting the proper distance later.

Cut the DOM tube and install the shifters. Secure the assembly enough to shift the Atlas as if it were running. You will be taking this back apart so don't get too serious about the torque. Install the shift assembly.

You will need to be able to shift the Atlas into Low to be able to set the length of the DOM tube to proper length. The best way to shift an Atlas is while the gears are turning. Since the drive shafts are disconnected, you can crank the engine and put the Atlas into gear without fear. My shifts were very stiff at first and it was a little concerning. I have a manual transmission, so I could manage the level of spin as I was trying to shift the rear axle into Low. As it turned out, it shifted best when I didn't feather the clutch and just tried to shift at an idle.

Once you get the rear axle into Low, stop the engine and look at where the brass yoke is positioned. The distance moved in and out of the Atlas from neutral is actually very small at the shifter base.

You will need to use the rear shifter Low position to estimate where the front shifter Low position will be. Remove the shift assembly to get the DOM tube out. Reposition the shift housing to a point that simulates where you would like for your front shifter to sit when it is in Low. I found that about a half an inch from the tub worked for me.

Measure the distance and cut the DOM tube to match. Re-install the shifter housing. Don't get too crazy with torquing down the shifter housing and leave off the clips at one end of the all-threads that link to the brass shifting yokes.

Underneath, you should have something that looks similar to this:


At this point, you will want to experiment with shifting the Atlas into all of the running positions and adjust the threaded links until you are satisfied with the handle positions. You will need to do this with both the console off and on. Follow the instructions provided for this adjustment. I recommend putting the shift knobs on when working with the console on.

Once that you have adjusted the shift links to your liking, you will need to fit the heat shrink tubes to ensure that the all-thread link cannot spin. These need to be heated with a heat gun and not just a hair dryer:


At this point, I noticed that the E-Brake handle seemed very close to the 4-Speed shifter. It didn't like the thought of raking my knuckles on the shifter every time I set the emergency brake, so I bent the handle slightly away. DO NOT do this:


Whatever allows the button at the top of the E-brake to move gets trapped if you bend this handle. I bent mine back and it works again. It doesn't interfere with the shifter like I was thinking. The shifter sits very high, but that might be because I did not use a body lift like recommended.

You should probably fit your shifter boot now, before you start the next step. I didn't and was surprised by how the boot needed to fit to keep from binding. Also, adding a bit of grease to the handles where the boot touches will make the fitting easier and the manual says that it will reduce binding during regular use.

The hole in the tub that the shifters fit through will now be too large for your needs. You don't want fumes, water, and other debris coming in, so you will need to cover it partially. The plate that AA recommends looks something like this:


But what you will need is closer to this:


Even so, I still needed to add a small piece of sheetmetal on the left to fill all the gaps under the boot:


After putting the console back in and all of the shifter knobs in place, my install looks like this from the inside:


At this point, you are ready to put the carpet and console back into place and to reinstall the driver's seat.

Since the Atlas has been spun a bit by this point, it is safe to mark the fill level of the sight tube with a zip-tie. This will be your fill level for the future.

Officially, you have completed the Atlas install, but in reality, there are more steps to be done. In a simple form, you will need to reinstall the drive shafts, install the belly skid plate, and check the driveline for suspension issues.

All this assumes that you didn't change anything regarding those items.

Most likely, you will.


More to come....

[Mike]

Visual Ratios

One of the cool things that I was able to capture while I was working on the shifter positions is the yoke spinning at the different ratios that the Atlas offers. Here are the ratio differences visually.

1 to 1:


1 to 2.73:


1 to 4.3:


1 to 11.7:


I'm thinking that at 1:11.7 you could get out of the Jeep, eat lunch, and watch your Jeep roll through the obstacles without you!

[Black & Tan TJ]

Very nice Mike. When I get around to this you will be the first call I make.

Cheers! Tom

[curtis]

Great job and report.

[RAT]

How much to have one installed in the 90631 zip code?

[Mike]

Very nice Mike. When I get around to this you will be the first call I make.

Cheers! Tom

No problem. Let me know and I will be happy to help!

How much to have one installed in the 90631 zip code?

YOU on the other hand.....
Hmmmm...

[1 Bad F N Z]

Did you have to strengthen the frame in the middle, so it doesn't start to bow?

[Mike]

Did you have to strengthen the frame in the middle, so it doesn't start to bow?

Ha! Not yet, but we'll see. The Rubicon should test the design for sure!

[Mike]

The Aftermath...

So even though the Atlas is in, there were several fun things to deal with afterwards.

The front drive shaft needed to be 7/8" longer. Not a big deal, so I left the front shaft as is and reattached it.

The rear drive shaft was a totally different story. The shaft was already as short as it could be made with stock shaft parts. Now it needed to be 2-5/8" shorter. Time for a custom shaft or a rear stretch. The rear stretch is coming in the future, but now isn't the time. So, a custom shaft seemed to be the best answer.

I talked to Randy at Driveshaft Specialist in Azusa and to the folks at Tom Woods. Both said that I could cut the shaft that I but I shouldn't plan on this as a long term solution. Tom Woods could build me one for around $300 +.

Since I want to eventually stretch the footprint of the Jeep, I chose to save the custom money now because I will need another custom one in the future anyway. So to the bandsaw I went:



Both the shaft and the tube had to be chopped:



Cleaning the splines inside and out and chamfering the shaft end took the most amount of time. I greased the two parts and slid them together, then pumped the tube housing full of new grease. The initial install looked like this:



It only took one run to work and back to learn that this was not a long term solution. Without the dust cap end, the tube leaks grease from the splines and spins it across the tub. Randy at Driveshaft Specialist suggested that a dust boot should fix the problem for the short run, so I modified a boot that I had and zip-tied it into place. After filling the tube housing with grease until I could see a bit oozing from the boot, it seems to be very sound:



I have been driving it to work everyday for a week and the shaft has not lost any grease. I think that I have my short term solution.

The other piece that still needed work was the belly skid plate. The ProComp lift that I have has a smooth plate that fits at a stock level. It is removeable without having to support the transmission due to the cross frame beam that I mentioned previously.

Due to the deeper dimensions of the Atlas, the plate could not be installed. I cut out a section of the plate and fabricated a mounting system that allowed for the extra space that the Atlas required. In the process, I also created a way to remove the new section so that oil changes to the Atlas would be a breeze.

The only concern that I have is that I expect the rocks to put my welding skills to a real test. I am sure that I will have to learn to compensate for this extra section hanging lower:


At last! I am finally to a point that I am ready to do some off-road testing and practicing. I just need to find some time to run up to Cleghorn... Hmmm, and maybe some sushi at Silverwood Grill!

[RAT]

Looks good Mike. The Rubicon will help you with that weld testing for sure. You did a real nice job there.

[6spdYJ]

Way to go on the driveshaft. That's awesome!

[jonah]

Major upgrade for Mr.Green, nice work!

[1 Bad F N Z]

let take it to Cougar Buttes and test it, Kevin.

[aw12345]

So even though the Atlas is in, there were several fun things to deal with afterwards.

The front drive shaft needed to be 7/8" longer. Not a big deal, so I left the front shaft as is and reattached it.

The rear drive shaft was a totally different story. The shaft was already as short as it could be made with stock shaft parts. Now it needed to be 2-5/8" shorter. Time for a custom shaft or a rear stretch. The rear stretch is coming in the future, but now isn't the time. So, a custom shaft seemed to be the best answer.

I talked to Randy at Driveshaft Specialist in Azusa and to the folks at Tom Woods. Both said that I could cut the shaft that I but I shouldn't plan on this as a long term solution. Tom Woods could build me one for around $300 +.

Since I want to eventually stretch the footprint of the Jeep, I chose to save the custom money now because I will need another custom one in the future anyway. So to the bandsaw I went:



Both the shaft and the tube had to be chopped:



Cleaning the splines inside and out and chamfering the shaft end took the most amount of time. I greased the two parts and slid them together, then pumped the tube housing full of new grease. The initial install looked like this:



It only took one run to work and back to learn that this was not a long term solution. Without the dust cap end, the tube leaks grease from the splines and spins it across the tub. Randy at Driveshaft Specialist suggested that a dust boot should fix the problem for the short run, so I modified a boot that I had and zip-tied it into place. After filling the tube housing with grease until I could see a bit oozing from the boot, it seems to be very sound:



I have been driving it to work everyday for a week and the shaft has not lost any grease. I think that I have my short term solution.

The other piece that still needed work was the belly skid plate. The ProComp lift that I have has a smooth plate that fits at a stock level. It is removeable without having to support the transmission due to the cross frame beam that I mentioned previously.

Due to the deeper dimensions of the Atlas, the plate could not be installed. I cut out a section of the plate and fabricated a mounting system that allowed for the extra space that the Atlas required. In the process, I also created a way to remove the new section so that oil changes to the Atlas would be a breeze.

The only concern that I have is that I expect the rocks to put my welding skills to a real test. I am sure that I will have to learn to compensate for this extra section hanging lower:


At last! I am finally to a point that I am ready to do some off-road testing and practicing. I just need to find some time to run up to Cleghorn... Hmmm, and maybe some sushi at Silverwood Grill!

I would make the skid a lil longer to protect the oil level fittings, you snap the bottom one of on a rock and you will not be a happy camper just saying