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Revolution Gear 3:1 install ('99 Trooper manual)

19K views 59 replies 3 participants last post by  Enemigo 
#1 ·
I couldn't find a write up on how to do this install. I think it's way past time to do so. I'll do all the work and take the photos with help from people on here. I'll change the thread up as I go in order to have all the steps be in the correct order. I'm going to start the how-to with the transfer case already removed from the transmission and on a work bench. I got stuck pretty quick, so I'll post what I have for now and see if I can get some help from members here when I need.

Let's go!

With the transfer case out and drained, make sure you clean up the outside to prevent stuff from falling in once you open it. I used various brass wire brushes and a pick here and there to dig rocks and dirt out of hard to reach places. I kept my vacuum near by to keep the dirt pile to a low roar as I went along and found stuff I had missed on prior passes. I'll post the Indy4x instructions in italics.



Starting at step 5 of the install instructions provided by Independent4x, remove the four 12mm bolts on the low shift unit and remove. I tried to separate the case first, and had difficulty removing this as the case was preventing the ball from coming out. After taping the case with a soft hammer it vibrated out. Shouldn't be a problem if you do this step before pulling the case apart.


Next remove the 9 bolts and the 2 stud bolts from the house. NOTE! Mark the location where the 2 stud bolts were removed for later assembly. I used grease paint. If you forget, they are at the bottom, on either side of the drain plug. It starts to separate a bit on it's own and you can get a small pry tool in to help it along.


Remove the high-low speed ball detent unit. (This is a 3/4" hex fitting (19mm) that is located on the outside of the housing inline with the shift rail shaft. Remove the hex fitting, spring and ball. DO NOT leave the ball in the hole, as it will fall into the rail shaft hole when the shaft is removed. The yellow arrow indicates the correct detent. I removed both and the bolts, springs, and balls are identical.




Use a magnet to remove the spring and the ball. Any magnet (or a pick) will work for the spring, but you'll need a small enough magnet to fit down the hole for the ball. Pretty sure this is just some cheap one I picked up from Harbor Freight or whatever auto parts store.


Pry the housing apart. NOTE! The 2 locating dowel pins and all the internal shafts (expect the rear wheel drive shaft) stay with the front half of the housing.

This is where I'm stuck now. The case doesn't want to come apart any further, and I'm reluctant to keep prying. I've looked at other instructions on other boards and don't see anything about removing the drive shaft flanges.


Do I need to do this? What could be holding this together? Does it just need more gentle coercing?


That's all for tonight. Let's get all hands on deck and we can make a detailed thread together.
 
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#53 ·
Snap ring for the synchro. My best guess because you had the dog teeth backwards.
Inertia shot it out.
Or snap ring for one of the bearings.
Hope teeth are okay.
 
#54 ·
Here is the only damage I can see so far.



The interference, and the noise, is coming from these teeth making contact. This is on the gear where the dog teeth are I guess installed backwards. I'm going to go back through the thread to see what Lorenzo posted to verify. When I shift it into 4wd, the teeth don't hit, and depending on how I orient the case, the noise goes away as well.


There is still the issue of where those long metal strips came from. I've got that other gear in the other transfer case as well. Even though that one chip doesn't really bother me, I'm going to pull this gear from the other case to verify how the teeth sit. Also it will give me a chance to figure out the most efficient way to get this out on the case that counts.
 
#55 ·
lorenzo816 said:
I hope everything shifts smoothly. Looks pretty good to me except the synchro 'dog teeth' and I'm going to have to verify on a case once I get another one apart.
The book and my memory remember this as the orientation. If anyone has done a synchro gear on a NP case before, they are set the same way.
Looks like I've got them in backward, and those snap rings are probably what go blown out, just like Lorenzo suggested. Let's see if I can get it all back together and driving today!
 
#56 ·
Strips are the snap rings most likely.
Go back and read through what I posted on the last one I did and you'll be set.
Use that pick you have or something thinner stronger like a dental pick.
Now for the 4wd cluster, if the other is same count is just swap it for piece of mind.
That might cause skipping in 4wd but not positive - that would depend on how deep the chip is.
 
#58 ·
I'm thinking that you now don't have a Synchro also on the main shaft hub gear.
Which is good news that you don't have to do a full disassembly. I was thinking this was on the main shaft but since this is on the four-wheel-drive cluster, then you can just partially disassemble and swap the whole unit trying to keep collar in place so that the dog teeth don't spring out of the replacement.
 
#60 ·
I was so excited to be out test driving the Trooper that I forgot to update. I was able to pull the transfer case out of the vehicle, separate the halves, pull the 4wd shaft out, and replace with the undamaged 4wd shaft from the donor case, then button it back up and reinstall. All in a single day, which is a miracle for me. I'm sloooow when I work on stuff.

Anyway, everything seems to be working and no other damage was found inside the case. I did a test drive today, but haven't tested the low range again yet. I really liked what I felt when I tested it right before it broke though. I would consider this mod a success. I love the change the low gears provide. Now I'm hoping to be able to use less gas pedal on obstacles and give me more control. I wasn't sure how it would feel going from 2:1 to only 3:1, but it is a very noticeable difference. I can't imagine a Rubicon with 4.10:1, or my buddy's 4Runner with 4.7:1. The nice thing about these 3:1 is that most of my off road driving occurs during hunting, and 4:1 would be too low. In fact, the 3:1 might even feel too low for cruising fire roads. Thanks for the help of everyone that contributed to this build. It may not be the best how-to, but I'm glad that we finally have one.
 
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