Search turned up nothing, can anyone explain why JK's require a front driveshaft with a 4" or higher lift? I was told it hits the skid plate when you lift the jeep high enough, but I fail to see how mechanically just "replacing" the stock DS to an aftermarket prevents it from hitting said skid plate. That just doesn' t make sense therefore I'm thinking it involves something else like "you have to have a better front DS due to the extreme angle requiring a CV or long DS, similar to the rear.

With the TJ's you only needed to do the SYE and CV rear DS and if you just wanted more beef then you could do a front but not mandatory.

 

Well I have a 2.5" BB and I tore my front drive shaft boot this past saturday. With the added lift the angle for the front (rear also with the 2dr) becomes too steep (I believe thats the right term). Anyways, with an auto trans the strap that holds the boot on hits the trans oil pan causing the strap to rip the boot on the driveshaft that holds the grease in. With an after market DS, they are suppose to be thinner and have different joints (sorry don't know the term), thus preventing this problem.

 

wow, they can only be just "so" much thinner, I have to get under mine now and just check this out, sure sounds like it'd be easier to modify the skid plate than replace the entire driveshaft.

thanks though, makes sense from a physics standpoint, just not from a practical one....hence I need to crawl and investigate this.

 

The clearance issue I beleive is only with the Auto Trans.

 

That is correct.

 

^^^^x2^^^^ i have an auto

 

woohoo...I have a manual...no worries...hakunamatata therefore...

 

Here is WOL explaination on the need to replace driveshafts.

Q: Are new driveshafts needed after installing a lift?
A: You really should consider installing a new rear double cardin U-joint style drive shaft if you have lifted your Jeep JK Wrangler 3" or more and have a 2-door. This is needed because the short rear drive shaft of the 2-doors will be at a steep enough angle that the CV boots will wear out prematurely. However, in order to do this, you will need to buy a set of rear adjustable upper control arms so that you can properly set your pinion angle. 4-Door Unlimited models do not have this problem as their rear drive shafts are very long and a lift will not effect the angle of it too much. As far as the front goes, if you have an automatic transmission, you should really consider replacing the drive shaft with a double cardin U-joint style unit as well as the diameter of aftermarket shafts tend to be considerably narrower and will not come into contact with the skid plate. An alternative to this would be to remove the automatic transmission skid plate or cut out a notch along the edge to prevent the drive shaft boot from making contact with it.

 

Ok, So I have decided I'm going to notch the Auto Skid plate, buy rear-upper control arms and a rear Drive-shaft.

What double cardin u-joint rear axel shaft would you guy's recommend?

 

why are u doing all that with the 2.5 tf BB?? i have had it all flexed and flopped and drooped and dropped all with not a single issue..
no issues...

other side no issues..