Recently I have had a couple of guys that are just getting into Jeeping with stock Wrangler TJ’s (Yes there are still a few around) and one of the first questions I get asked is “What is a slip yoke eliminator (SYE) or short shaft conversion).
So here is the one on one on the SYE, there are a few different versions around but basically they are do the same job. They eliminate the sliding yoke joint on the transfer box end of the rear prop shaft, why would you want to do that? Well if you look at the rear prop shaft on the Wrangler TJ and YJ (not so much the YJ) it is very short and once you lift the suspension 2+” (50+mm) the angle the prop will run at will cause problems maybe vibration and at full articulation the yoke could bind.
The stock set-up on a Wrangler TJ. 
The shaft that the stock sliding yoke runs on. 
The heavy duty slip yoke eliminator fitted. 
The SYE installed in the Wrangler and fitted with a new prop shaft, note that the sliding joint is now in the prop shaft tube. Also using a double UJ joint (Americans refer to this as a CV joint) on the transfer box end allows for a lot more articulation so eliminating bind on higher lifts.
Another advantage of fitting a Heavy Duty SYE is the increase in strength of the output shaft, as you can see from the photo below the increase diameter of the shaft. 
As I said at the beginning of this article there are many different versions on the SYE, some involve cutting the stock shaft down, drilling and fitting a flange. Another version does away with the speedo drive cog converting to impulse output but also making the short shaft conversion about 1.5” shorter allowing for a longer prop shaft which helps with the higher lifts.
So if you are think of lifting your Wrangler more then a couple of inches then you are probably going to need a SYE so for more information or advice contact FTE 4x4 Specialists Ltd.
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