Originally posted by jobob:
Is there any major difference, performance wise, between a cv sye and an sye using 1310 ujoint? I am planning on the RE 4.5 extreme lift on my 90 yj and just haven't decided which sye kit to buy. Would it be easier to cut and tap the existing shaft, as with the RE sye, or just replace the shaft all together as with the more expensive kits? I just worry about opening up the t-case. I feel pretty comfortable doing some mechanical work, but am far from a pro. Any info would be appreciated.
There's definately a huge gain in using a CV over just a straight u-joint shaft. The CV is what allows the more extreme angles on the driveshaft. There really isn't much point in putting in an SYE if you're not going to use CV shaft. The only thing the SYE will do for you in that case is allow you to disconnect the rear driveshaft without spewing your tcase fluid.
There are big differences in the SYE kits. The "hack and tap" kit from RE is no worse than the Currie kit. Same thing, except Currie does the hacking and tapping and gives you a better bearing on the rear output. But you still are left with only 1" of splines on the rear shaft.
The JB Conversions kit (there are others with a different name) supply a new 241 shaft. This is the strongest SYE you can buy.
The MIT kit cuts the shaft down, builds up the around the spline area, resplines the shaft and rehardens the shaft. This kit also nets the longest driveshaft.
I ran the MIT kit for 5 years with any problems at all. When I bought it, it was the only SYE kit. It too has made it's way into my son's Jeep now. So it's still chugging away.
The MIT kit would be my second choice if I were buying one today. You just can't beat the strength of the 241 shaft kits. I'd guess the 241 kits and the MIT kit are about the same price too.