it depends on the amount of lift you have and the length of shocks you have to go with them. an aftermarket drive will solve the later and for the most part, the prior as well so long as you're not going too tall.

yes. even completely stock, your drive shaft comes really close to the exhaust at a full droop. if you keep stock length shocks or close to it, you should be okay with a 2" lift as the shocks will act as limiting straps. however, your cv boot will still be in a state of pinch and it will fail sooner than later.

this effects 2-door and 4-doors alike as both have the same front drive shaft.

 

I must have gotten lucky here. I have a new 2012 Rubicon 2-door that I just put a 3.5" RK X-factor lift on. The lift netted a little over 4" and I've got about 5/8" of clearance between the crossover and the front driveshaft with the vehicle under it's own weight. The driveshaft does contact at full droop though. I had to loosen the exhaust when I put the lift in.

I bought the AFE y-pipe as well but haven't put it in yet. I haven't had any clearance issues with the crossmember though.

 

It's understandable that this subject (and others at time) is confusing when we're all using the same word "lift" to have two different meanings.

1) measured increase in height at full rest over a stock suspension and/or
2) measured increase in travel/articulation at full extension over a stock suspension.

Two different measurements.

 

I have the same lift and also installed the aFe y-pipe along with an aftermarket front driveshaft. You may still need an aftermarket driveshaft even though you will move the crossover pipe. The angle of the stock driveshaft is bad after a lift is installed and it is only a matter of time before it will fail.

 

http://www.youtube.com/watch?v=oKBlEpMaJC4

 

Its been educating you wrong. You will NEED a driveshaft as well as the TF spacers in order to clear the exhaust under full droop. AFE's crossover pipe you can still use the factory shaft.

 

so that it's clear, you can only use the factory shaft so long as the lift you have. the engine/tranny/t-case sit at a much steeper angle than previous years and ANY AMOUNT of lift will cause the cv boot at the output shaft to sit in a continuous state of pinch. this WILL cause it to fail sooner than later and that would be the end of your factory shaft.

 

Does it do something different than just move it back?

 

Correct. But TF's "fix" to this is not a fix. I, like others have bought the 60 dollar TF spacers to resolve the problem because thats what TF said. It does not solve the problem, it does give more clearance but under full flex you are still rubbing the crossover.

 

Both the TF spacers and AFE crossover do the same thing. The TF moves the factory crossover back about 1-2 inches. The AFE pipe replaces the factory crossover with a new crossover that is relocated behind the cross member instead of in front of it.