Advance Adapters SYE
& CV Drive Shaft
What You will Need
Advance Adapters SYE for NP231
• CV Drive Shaft (Order to Fit)
• Adjustable Rear Upper Control Arms
• 10,15,19,21mm Socket/Wrenches
• 10mm - 12 Point Socket
• 5/16,1/2,1-1/8" Socket/Wrenches
• 10mm Allen Bit
• Ratchet
• 3" Ratchet Extension
• 1-1/2" Crescent Wrench
• Torque Wrench - 150 Capacity
• Breaker Bar
• Large Monkey Wrench
• Flat Head Screwdriver
• Rubber Mallet
• Flat Wood Chisel
• Hammer
• HD Snap Ring Pliers - Lisle 49200
• Lock Ring Pliers - Lisle 44900
• Needle Nose & Regular Pliers
• Angle Finder
• 2 - Jack Stands
• Floor Jack
• Gear Puller w/5"+ Reach
• Gasket Scraper
• RTV Gasket Sealer
• 2 - Pints ATF+3 or Higher
• Bottle Pump or Yorker Spout
• Oil Catch Pan
• Rags

What Comes with the
Advance Adapters Slip Yoke Eliminator Kit

• Die Cast Tail Housing
• Main Output Shaft
• Rear Yoke Seal Washer
• Rear CV Yoke
• Rear Yoke Nut
• Front Yoke Seal Washer
• Speedometer Ring Gear
• Speedometer Ring Gear Snap Ring
• Tail housing Plug & Washer
• 207 Open Ball Bearing
• 207 Bearing Snap Ring
• Mode Retaininer Ring
• Tail Housing Seal

Pros & Cons of Installing an Advance Adapter Slip Yoke Eliminator & CV Drive shaft
• Eliminates vibrations caused by incorrect drive line angles typically associated with lifted Jeeps.
• Increases the life of your drive shaft U-joint. and prevents pinion shaft oil seal leaks or other leaks caused by drive line vibrations.

• The cost of a slip yoke eliminator which costs about $250
• You will need to buy a CV drive shaft which will cost about $275
• You will need to buy rear adjustable control arms which cost about $200

In a nutshell, this isn't exactly cheap to do but in my opinion, worth every penny in the long run.
Advance Adapters Slip Yoke Eliminator (AA SYE)
& CV Drive Shaft Installation on a Jeep TJ

Whenever you lift a Jeep TJ above 2" (and sometimes even just 2"), your drive line will be off enough to cause what is known as drive line vibrations or "vibes" for short. Because of this, most lift kits will include a transfer case skid plate lowering kit to help restore your drive lines back to or at least closer to stock. For the most part, this will do the trick but then you have to ask yourself, do I really want to lower the very part of my Jeep that I just spent a boat load of money to raise up? Yes, there are other ways you can kind of get around this like installing a 1" motor mount lift and/or lowering your transfer case skid plate just a bit with washers and you can even try to convince yourself that the vibes are gone.... but believe me, once you install an Advance Adapter slip yoke eliminator or AA SYE for short and a CV drive shaft, you'll know that you had just been kidding yourself. Once installed, your Jeep will drive like butter. It will also be quieter which is something I hadn't expected and you will be doing your U-joints a huge favor.

NOTE: This AA SYE and CV drive shaft installation write-up is for a Jeep with an NP231 transfer case only.
Here is a pic of all the parts you will get with your new AA SYE. Before you being this installation, do yourself a favor and make sure that you have ALL the tools listed on the left. Trust me, you will not be able to finish this job without them.

1. Due to the lack of work space and my overall general laziness, this write-up will be performed while the transfer case is still on my Jeep. To begin, park your Jeep on level ground and somewhere you won't mind sitting under for a few hours.

2. Put your Jeep in gear, engage the emergency brake and then shift your transfer case to 4WD Low.

3. Climb underneath your Jeep and remove the 2 metal band securing both ends of the rubber boot on the transfer case output shaft using a pair of pliers.

4. Now, roll over towards the Jeep's rear axle and remove the 4 bolts and 2 yoke straps securing the drive shaft to the rear axle using a 5/16" socket or wrench.

5. Set aside your yoke straps and bolts, grab the drive shaft with one had and then give it a tap with a rubber mallet to free it from the pinion shaft. Loosely re-attach the U joint bolts and strap on to the pinion shaft for safe keeping.

6. You can now remove the drive shaft from your transfer case by simply pulling it toward the rear of your Jeep.

7. Now, remove the 4 nuts securing your transmission mount to the transfer case skid plate using a 1/2" socket.

8. Place a jack stand underneath the bell housing of your transmission and then slide a floor jack under the center of your transfer case skid plate and then raise it up until it puts a little pressure on it. As you can see in the pic to the left, I also used a short 2x4 piece of wood to help distribute the load.

9. Remove the 6 bolts securing your transfer case skid plate to your Jeep's frame rails. On a 1997-2002 Jeep TJ, you will need a 3/4" socket. 2003+ TJ's use a metric bolt that is similar in size but I do not know what it is. A breaker bar will come in handy here and if you live in the rust belt of America, some PB Blaster on the bolts will help out a lot.

10. With the bolts remove, slowly lower your floor jack just a little and make sure that your transmission is now resting on top of the jack stand you place under the bell housing. Then, grab the lip of the transfer case skid plate and roll the whole thing out from under your Jeep. Set your skid plate aside for now

11. Climb back under your Jeep and remove the 4 bolts attaching your front drive shaft to the transfer case output shaft using a 5/16" wrench. Carefully lower it to the ground and then proceed to remove the 4 bolts attaching the drive shaft to your front axle using the same wrench. Set your front axle someplace out of the way.
12. Place an oil catch pan under your transfer case, loosen the upper fill bolt using a 10mm allen bit and then remove the lower drain bolt using the same allen bit. Allow as much of the fluid to drain as possible before continuing.

13. For some reason or another, some Jeep TJ's came with just a slinger on the output shaft while others came with a dampener or harmonic balancer. As you can see in the pic to the left, my NP231 came with a slinger which required the use of a gear puller (borrowed from Autozone) with a 5" reach to extract. If your Jeep has a dampener instead, a gear puller will work just fine and much in the same way too.

Remove the output shaft seal by tapping a flathead screwdriver with a hammer all the way around the seal until it comes off.

15. At this point, you will need to unplug the speedometer wiring harness connected to your transfer case Tail housing To do this, you will need to use a small screw driver to slide out the red key locking the connector in place. (See photo to the left)

16. Examine the position of your speedometer gear housing in relationship to your Tail housing and make a note of where it is indexed. Then, using a 1/2" socket, remove the retaining bolt and metal clip securing your speedometer gear housing to your Tail housing Firmly grab the speedometer gear housing and carefully pull it out.

17. Back at the output shaft, remove the inner and outer snap and lock rings using a pair of heavy duty snap ring pliers and lock ring pliers. Trust me, the right tool for the right job will make this a lot easier to do.

18. Now, remove all the bolts securing the transfer case Tail housing using a 10mm socket.

19. Using a rubber mallet, you should be able to give the Tail housing a couple of good whacks to free it from its bond to the rest of the transfer case.... or so I was told. I ended up using a flat wood chisel and a hammer to separate the two. Be aware, your transfer case is made of aluminum and can be damaged easily. If you need to go this route, pay special care not to damage the mating surface of the transfer case. The tail housing will be replace with the new one provided by the AA SYE kit so if anything, it is expendable.

20. Moving back over to the front of your transfer case, remove the front yoke nut using a 1-1/8" socket. This nut is on very tightly and a breaker bar and a large monkey wrench to hold the yoke will be needed to remove it. Or, if you have an impact wrench, that'll do the trick too. When you pull the yoke off, be sure to remove the rubber washer that will be on threads of the shaft.

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