I just installed a 3 long arm TF and changed both shafts, nothing to it. I went with coast from David at Northridge. They came with a year warranty and are smooth as glass no problems at all. If you run the mfg shafts they will last abnout two off road trips and start leaking. then they snap. Call David and I am sure he will get you a good deal. He has always been fair w/ me.

good luck! just my .02

 

I had stock shafts with 4 inchs for at least 5000 miles with no problems. Been on most of the level 7 and 8 trails in Moab with this setup. Finally installed a new front and doing the back in a couple of weeks. My unlimited was lifted when I bought it so I don't know exactly haw many miles are on the stock back driveline while lifted, but the lift and shocks looked old and rusted when I changed lifts. I have 14500 miles on now with the stock rear.
I recommend changing out the drivelines. But you do have some time.

 

A double Cardan joint is a constant velocity joint that has 2 contiguous U joints. It is used mainly to accommodate larger drive shaft angles (created from suspension lifts) without binding.

1310 and 1350 are two sizes of U joints commonly used in JKs. 1350 is larger and stronger U joint, but some designs can bind at lower drive angles than 1310s.

CVF and CVO are the type of connectors (flange, slip yoke) of the drive shafts to the axles or transfer case.

 

so are most of you running 1310's or is it worth the extra money to just get the 1350's now?

 

I got the 1310s from Tom Woods. Quote from their web site: "Unless you plan on beating the vehicle really hard, we believe the 1310 series front drive shaft would serve most people well. Likewise for the rear drive shaft."

 

I've been running the stock for about 50k km, (30k miles) and have never had a problem. I have a 4.5" aev lift. I have recently changed my front to a tom woods and have the rear but just being lazy. Will the stock eventually fail? Yes. But I wouldn't panic to change it. Do your homework and ask alot of questions. If you want some good info, when I called around looking about a year ago I called Tom Woods and he actually answered the phone and explained it all to me like a 2 year old. 4 weeks later I called him up and ordered one. I liked the fact that he didn't push his product he just gave me the strait goods.

 

Sorry but I did not look at the first page. The big problem is 2 door or 4 door!

People with 4 doors the angle is less so they have little to no problems.

2 door has a much shorter drive shaft so the angle is greater.
I agree with the 1310's break here not an axle or ring gear.

I have a 2 door and with the 2 1/5 BB the rear seal on the drive shaft was leaking. I was not going to chance it going to a 3 inch long arm

 

I got a JE Reel 1310 HD for the front and a 1350 for the rear from David at Northridge. Couldn't be happier, and it uses all yokes except for the transfer case rear output which is a flange.
Amybe I'm old school, but it just doesn't look right if it doesn't have a yoke at the pinion.