How driveshafts and lifting your rig works? cause I'm planning on lifting my XJ but, I don't know how if the driveshaft doesn't extend or anything, how is it that I can get a lift and not need an sye? unless I have one of them double something driveshafts that extend and compress. so if I lift my rig 3.5 I can still use my stock driveshaft if I don't need an sye? Im not sure how this works... Kinda hard to explain as well so if anyone can help it would be awesome. Trying to expand my knowledge a lil

 

Your front drive line has a slip yoke in it so it alows it to extend an well the rear off your trans is a slip yoke so it alows it to do the same thing you dont really need a sye tell your going 4.5 + lift so 3.5 inches will be fine with all stock drive trai.

 

yea you will be fine. i run 4.5 with 32 and im fine just a t-case drop

 

Iv got a 3.5 RE lift I'm planning to put in once I get shocks. so how does a stock driveshaft work if I'm stretching my driveline? Is it because of the stock slip yoke let's it extend?

 

the angle of the drive shaft gets worse putting strain on the universals but 3.5 should not do that

 

The front driveshaft is a double cardan. It has the slip in the shaft. The rear shaft is a slip yoke. The yoke slips in and out of the output shaft.

 

So if you extend the driveline with a lift y wouldn't you just put a longer Ds instead of an sye&ds?

 

Because the slip yoke is only so long.

It's not the length that matters as much as the travel.

Plus, when you are at the limit of your slip yoke it's sticks out the back of the t-case much farther and applies a LOT more leverage.