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Technical / Installation Articles - Engine / Drivetrain

Teraflex Extreme Short Shaft

Article written by Starbucks

Date Added: 05/19/2006

Since I bought my Jeep, it has grown little by little. First I put on a 2 in budget boost, next 4 inch springs, and then 5 inch springs with a one inch body lift. Every time I lifted my Jeep, I ask myself the question ?do I need a slip yoke eliminator??

Researching this question, I learned that YJs and TJs come from the factory with some slight driveline vibration. Knowing this, it?s easy to see the importance of installing a slip yoke eliminator with any modification that you do. A transfer case drop is another option. It will make the driveline angle less severe, but it is much less effective and will reduce ground clearance. I chose to go with the T-case drop for a long time because I thought other mods were more important. Now looking back, I realize that installing the SYE should have been one of the first things I did. After installing the 5 inch lift and an 8.8 rear axle, the transfercase drop wasn't cutting it and I had to do sometheing better. Being forced, to put up the funds for an SYE, however, was a blessing in disguise.

Which slip yoke eliminator to choose?

Four different types of SYEs are available. The hack and tap SYE is cheaper than the others but much less effective. Another option is an SYE that is machined from your stock equipment. This option is better than the hack and tap but still not as effective as a standard SYE. The standard SYE comes with a new housing and beefed up output shaft and is an excellent choice for most applications. The fourth option is the extreme short shaft, which is 3 inches shorter than the standard SYE and 1 ½ inches shorter than an Atlas transfer case. It comes with a new housing, magnetic speedometer, and a beefed up shaft. I chose to go with Teraflex's extreme short shaft for three reasons. I wanted to do a tummy tuck, have a heavy duty output shaft, and have a SYE compatible with my 8.8 rear axle (which is off set a little to one side so I wanted the longest driveshaft I could have).

How to install a Slip Yoke Eliminator

I suggest having a clean work area and taking your time. Avoid getting any contaminant in the t-case.

Materials Needed

2 quarts of ATF III or applicable fluid
RTV silicone
Floor Jack/ Jack Stands
½ drive ratchet
¾ in socket
Yoke socket
3/8 drive ratchet
8mm/10mm/12mm 12 point socket or wrench
Set of metric sockets
Allen wrench
Flat screw driver or pry bar
Specialty C clip pliers (makes the job easier but not necessary)
Snap ring pliers (makes the job easier but not necessary)
Large three jaw puller (loaner tool from Autozone)

Time: Four to Six Hours for installation. (Average guy)



1. Begin by setting the emergency brake and blocking the tires.

2. Next use a jack stand or floor jack to support the transmission and transfer case right in front of the skid plate.

3. Once everything is secure you can remove the rear driveline and drop the transfer case skid plate.

4. Separate the front Driveline from the case and remove the yoke nut.

5. Next use an Allen wrench to drain the fluid from your case.
 This does not apply to everyone but if your out put shaft has a harmonic balancer you will have to remove it with a three jaw puller.

6. Remove the bearing seal. (you will have to pry it out)

7. Unbolt and remove the speedometer mechanism.

8. Use snap pliers remove the snap ring.

9. After the snap ring is removed, remove the bolts from the tail housing. Use a small pry bar to split the tail housing from the case. There are 2 tabs that make that make good pry point.

10. After the housing is removed, remove all the bolts that hold the two halves of the case together. Carefully note the location of each bolt. Next split the case with a screwdriver. Use only the two slots in the case. Do not pry any where else on the case or you may damage the mating surface. Pull the front half of the housing. Be sure you do not let the oil pump fall. Take a digital picture or study how things look. They should look the same when the installation is finished

11. Pull the front shaft and rear shaft out along with the chain.
 I suggest taking a picture or set the rear shafts side by side so you have reference to how to install the gears.

12. Before installing the gears on the new shaft, grease up the mating areas. After the gears are installed, grease up the front portion of the shaft.

13. Next lay the chain over the front shaft and new rear shaft and install them simultaneously exactly how they were removed. Be sure it looks exactly as it did before you removed the stock shaft

14. Once they are set in the case, grease up the rear portions of the shafts.

15. Apply a thin coat of RTV to both halves of the case then reinstall the oil slinger tube & slinger.

16. Next slide the rear half of the case and the oil pump in place. Install the bolts and torque to 30 lbs.

17. After every thing is torqued, install the speedometer mechanism.

18. Apply RTV to the housing mating surfaces and install the new tail housing.

19. Once the housing is torqued down, install the yoke and torque the yoke nut to 180 lbs. Install speedometer sending unit

20. Reinstall the front yolk and driveline. Then install rear driveline.

21. Add oil, reinstall the skid plate, remove the Jack and blocks and you are done.

Installation Issues

Information provided by Tera Flex: Earlier 231 applications with mechanical speedometer cable require updating to an electronic speedometer.

Final Thoughts

Driveshaft Selection
As always, when we need a driveshaft here at MoabJeeper Magazine there is only one choice and that would be Tom Woods. Hands down you can't beat the quality, craftsmanship, service time and above all else Tom Woods, the man himself, will take time to help you solve a problem and get you set up properly.

Overall I am very happy with my Tera Extreme Short Shaft. Drive line vibrations are gone and I feel much more comfortable knowing I got a "Woody" transferring power to the rear axle.


Purchase / Vendor Info

Vendor Name: Teraflex
Address: 5251 South Commerce Dr
Murray, UT 84107
Phone: 801-288-2585
Website: http://www.teraflex.biz/

Our Thank You's!

Tom, thank you once again for helping us out with a proper set up for this install between the factory NP231 and our Ford 8.8 conversion rear axle.

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