JB Super Short SYE Installation

By Mike Forbes

Note:  This installation write-up of the JB Super Short SYE installation is provided courtesy of Mike Forbes.  Mike was doing the install on his 2005 TJ and asked if I wanted to put the info on the site.  Since the site is all about sharing this kind of work with others, I was happy to accept his offer.  So here it is, direct from Mike.   And Mike….thanks again for providing this info for everyone else to use.

With a Rokem supplied OME suspension and a AEV Tummy Tucker installed, a new rear driveshaft and SYE was called for. I chose the JB Super Short so I could run a longer drive shaft. On this project my driveshaft ended up at 18 3/16″ from yoke to yoke, Tom Woods built the new driveshaft. Your installations will vary so do not even pondering ordering this size until your installation is complete, your rear upper control arms are installed and the proper pinion angle set.

Tools used:

Snap Ring Pliers, a good pair with long tips to get into the tail housing. I managed with a pair of Lock Ring Pliers, I used Lisle 44900 pliers I ordered from Amazon, they didn’t open quite enough but I place the tip of a slotted screw driver in between the ring and the pliers and that was enough.
10 mm 12 point for the transfer case.
18mm Socket for removal of center skit bolts.
1/2″ Socket for removal of transmission mount nuts.
15mm Socket for removal of the transfer case bolts.
10mm Socket for removal of transfer case tail housing.
10mm hex socket for the drain plug.
8mm socket for Driveshaft removal.
1 1/8 socket for Yoke nuts.
Cold Chisel.

Note:  This was done on the Jeep to save time, one could just as easily remove the transfer case from the Jeep.

Step 1. Support the transmission with a jack stand.

Step 2. Place a floor jack under the center skid.

Step 3. Remove the 4 1/2″ nuts connected to the transmission support.

Step 4. Remove the 3 18mm bolts from each side of the center shovel.

Step 5. Slowly lower the center skid and put somewhere out of the way and off the jack. Be careful! This skid is heavy and hard to balance on a floor jack!

Step 6. Remove the Front Drive Shaft with an 8mm socket. I marked mine for position before removal.

Step 7. Remove the front yoke with 1 1/8 socket and an impact wrench. I put my transfer case into 4HI with the Jeep in gear and removed the nut.

Step 6. Remove the metal bands on the rubber boot on the stock rear drive shaft, they twist off easily with a set of pliers.

Step 7. Remove the rear drive shaft from the yoke on the rear differential. This is done by removing the 4 8mm bolts holding the 2 straps.

Step 8. With the straps removed, slid the drive shaft off the output shaft of the transfer case.

Step 9. Drain the transfer case by removing the 10 mm hex drain plug.

Now comes the fun part. Some TJs have a harmonic balancer on the output shaft of the transfer case. Some don’t, I was lucky enough to have one.

Step 10. To remove the harmonic balancer you will need 3 M6 2inch bolts fully threaded.
Preferably grade 10.8. Note this is metric grading not standard which we are all familiar with. Grade 10.8 would be close to grade 8 for standard bolts. I had to use Grade 8.8 metric for this removal as I could not find 10.8. I bent several bolts in the process.

If you have a tap for M6 clean out the treads, if not PB Blaster them a lot and spray the bolts down with WD-40 so they thread easily. Insert the bolts and turn them all evenly and the harmonic balancer will slow pull itself off. Note: This will damage the tail housing but since you adding a super short housing anyways this is not an issue. I had to swap bolts as my weak bolts could not handle it and bent, but I swapped out them before they broke and the balancer came off without incident.

Step 11. With the harmonic balancer off you can see the rear seal. Place a cold chisel between the seal and the tail housing and tap with a hammer to remove the seal.

Step 12. You will see a a big snap ring holding the tail housing to the output shaft. Using our snap ring pliers and safety glasses, remove this inner ring. Note this can be a pain as my snap ring pliers did not have a snug fit in the holes, I needed fatter tips. Patience and several tries later with lots of pressure towards the transfer case so the pliers would not fall out I removed the snap ring.

Step 13. Remove the lock ring on the output shaft next. Using the lock ring pliers spread the lock ring enough to remove it from the output shaft.

JB Super Short SYE Installation

Step 14. Disconnect the wiring from the speedo gear housing. Slide the red tab outwards and then squeeze and remove the cable.

Step 15. Remove the speedo gear from the tail housing with a 13mm socket.

Step 16. Remove all bolts from the tail housing to the transfer case with a 10mm socket.

Step 17. The tail housing is held now only with some RTV. I used a dead blow hammer and screwdriver being careful not to damage the transfer case housing to break the rtv seal. Slide the tail housing off the transfer case.
Note: My instructions from JB said to leave the oil pump attached to the case. Well, I missed that part, fortunately I did not damage it on removal. It has a metal tube going into the bottom of it with can break the housing of the oil pump if removed improperly.

Step 18. Remove the 10mm 12 point bolt at the top of the transfer case.

Step 19. Remove the remaining 15mm bolts holding the two halfs of the transfer case together.

Step 20. On the right hand side there is a slot to insert a screwdriver to split the case open. Insert a screwdriver and pry carefully to break the RTV seal.

Step 21. Remove the case cover. Be careful to not the spring on the shifter fork, don’t lose this. Also notice the magnet in the bottom left, remove and clean.

Step 22. Remove the rear output shaft and front output shaft as a unit with the chain.

Step 23. Remove the rear output shaft from the chain.

Step 24. Remove the large lock ring on the end. Note: This was a challenge as the lock ring pliers needed to open about a 1/16-1/8 of an inch more than they would. I managed to get it started and worked it out.

Step 25. Transfer the gears and sprocket over to the new JB Short output shaft.

Step 26. Secure with new lock ring provided in the JB Short kit. Note: I used the help of a friend and a straight screwdriver to add width to my lock ring plier tips to open it wide enough to install.

Step 27. Carefully remove the shifter fork from the transfer case.

Step 28. Insert the shifter for onto the new shaft. Be sure to lubricate the parts with ATF before install.

Step 29. Insert the new output shaft and shifter for assembly back into the transfer case being carefull to install the shifter fork correctly into the shifter plate.

Step 30. Insert the front output shaft and chain.

Step 31. Reinsert the magnet in its slot

Step 32. Reinstall the spring on the shifter fork

JB Super Short SYE Installation

Step 33. Clean all surfaces of the old gasket material.

Step 34. Run a light bead of RTV around the case as shown in the picture above.

Step 35. Install the oil pump carefully onto the front of the case if it was removed.

Step 36. Carefully install the case half back onto the transfer case. Be careful to align the shift fork and and the front output shaft.

Step 37. Bolt it back together. Note: The top left bolt has a bracket that holds the speedo cable, make sure you bolt that back on.

Step 38. Torque the bolts to factory service manual specifications which on mine is (24-27 Nm or 20-25 ft. lbs.)

Step 39. Reattach front output shaft yoke and use some RTV on the threads and torque the nut to 122- 176 Nm or (90-130 ft. lbs.)

Step 40. Attach the tone ring to the rear output shaft. This is for the speedometer pickup.

Step 41. Grease the seal on the output housing.

Step 42. Run a bead of RTV around the output housing and install.

Step 43. Torque the bolts to the factory service manual specification which on mine is 20-27 Nm (15-20 ft. lbs.)

Step 44. Install rear yoke, RTV the yoke nut base and the threads, and torque to 200 ft lbs. This can be a challenge under the jeep, I had mine in 4 high and we ended up using a wrench to hold things as 200 ft lbs will turn things.

Note: failure to torque to 200 lbs will result in a speedometer with issues.

Step 45. Install Speed sensor and tighten.

Step 46. Reconnect speed sensor cable.

Step 47. Refill with ATF+4 and tighten fill and drain plugs.

You are done, depending on your gearing you may need to install a speedometer adjuster.

These are two popular choice Dakota Digital and the Speedo Healer.

Universal Speedometer Signal Interface