How durable are the stock JL driveshafts after installing a 3.5” lift?

[ChattVol]

Thank you for your time and replies!

Sure thing...regardless, I would start with the stock driveshaft and monitor it if you wheel it.

Sponsored

 

[scrape]

I imagine you heard that from Rock Krawler. My front shocks extend to 28" and the front OEM driveshaft boot is starting to tear and the flange is deformed.

28 is safe with stock control arm geometry. If you add caster it lays your axle back and puts a steeper angle on the driveshaft. OP also has a sport, so the distance between the pinion flange and axle center line should be slightly shorter which puts the ds at a shallower angle.

So there are some variables at play here and I’m not sure why people don’t just check since it’s 4 extra bolts. Unbolt your front DS from the flange, droop your axle, and see if you can easily bolt your DS back up without it binding or hitting anything.

 

[ChattVol]

28 is safe with stock control arm geometry. If you add caster it lays your axle back and puts a steeper angle on the driveshaft. OP also has a sport, so the distance between the pinion flange and axle center line should be slightly shorter which puts the ds at a shallower angle.

So there are some variables at play here and I’m not sure why people don’t just check since it’s 4 extra bolts. Unbolt your front DS from the flange, droop your axle, and see if you can easily bolt your DS back up without it binding or hitting anything.

Or simply flex it out and look at driveshaft clearance. I imagine most people that buy shocks longer than stock are doing it in conjunction with a lift that includes longer LCA's to increase caster so it tracks better.

 

[@CBEUnion]

I'm putting a 3.5 lif on my jlus and for sure changing that front drive shaft. Haven't decided on having a local drive shaft shop make it for me or not yet, but I will probably be putting on a 1350. I have asked about the stock shaft with a lift over 2" and each manufacturers rep said the same thing. Change it. Even if you go with a 1310, you'll still have a stronger, more narrow shaft and piece of mind.

 

[@CBEUnion]

This may help you. It helped me make up my mind. fwiw, [Banned Site] did have to take these shafts to a driveshaft shop to have them rebalanced. If you decide to change the shafts give a local shop a call before you pull the trigger. You might find that they are the same price for something that's basically custom and you have a local guy to go to if you have problems instead of a customer service call center person and a downed Jeep.

 

[LS7]

This may help you. It helped me make up my mind. fwiw, [Banned Site] did have to take these shafts to a driveshaft shop to have them rebalanced. If you decide to change the shafts give a local shop a call before you pull the trigger. You might find that they are the same price for something that's basically custom and you have a local guy to go to if you have problems instead of a customer service call center person and a downed Jeep.

At the end of this video, when he aligns the pinion angle with the new front driveshaft, he doesn’t seem to be concerned about the resulting change in caster angle. Shouldn’t he be? Thanks.

 

[@CBEUnion]

At the end of this video, when he aligns the pinion angle with the new front driveshaft, he doesn’t seem to be concerned about the resulting change in caster angle. Shouldn’t he be? Thanks.

I have to watch it again to see if he talks about how much it changed, but if it's only a small change and it's still in spec, then no need to worry.

 

[Sting_NC_USA]

Michael, thank you for your support! How many miles do you have on your lift? I’m trying to get a sense of longevity. Thank you sir!

30,000+ and still working well.

 

[scrape]

At the end of this video, when he aligns the pinion angle with the new front driveshaft, he doesn’t seem to be concerned about the resulting change in caster angle. Shouldn’t he be? Thanks.

If you have a FAD then you don't need to worry about front pinion angle unless you plan on going fast in 4wd.

If you deleted the FAD then you need to find a balance between pinion angle and caster. You will want to dial the pinion up high enough that the vibrations go away, and then the caster is what it is.

This only applies to aftermarket driveshafts. The stock driveshafts don't vibrate at crazy angles. They just wear out and break.

 

[D60]

If you have a FAD then you don't need to worry about front pinion angle unless you plan on going fast in 4wd.

If you deleted the FAD then you need to find a balance between pinion angle and caster. You will want to dial the pinion up high enough that the vibrations go away, and then the caster is what it is.

This only applies to aftermarket driveshafts. The stock driveshafts don't vibrate at crazy angles. They just wear out and break.

Honestly best I can tell the aftermarket is only using CV's to "reach" past the xmember. I mean pinion angle is NO WHERE near correct for a CV; your pinion should be pointing directly at your d/s and it seems to me even on a stock non-lifted JL it's not even close to that.

I'd love to try a basic non-CV shaft up front but clearance at droop would be an issue for sure. I've also wondered if a basic spacer at the t-case flange might work? It's common on square body Chevys to clear the exhaust after a lift

 

[Halstem1]

I’ve heard it all over the web, but it’s been my own experience. I bent that flange up with my Mopar lift, shocks only extend 26-1/2 inches. Hardly catastrophic. And the boots are junk. But I’ve never had u joint problems until extending 30” .

I was reading through this post the other day and made me think while I was under the jeep this weekend. I'm running the Mopar 2" lift with the provided shocks. I have not done any wheeling I would call extreme. As a point of reference, I was inspecting underneath to decide where I needed additional skids and can only find like 1-2 places where contact was made. None the less, I had some damage to my CV boot and the flange is slightly bent at the T-case. Also a spot where the driveshaft made contact with a factory skid or cross member. I'm not worried about it but was just surprised. Something I'll keep an eye on after trips.

 

[scrape]

Honestly best I can tell the aftermarket is only using CV's to "reach" past the xmember. I mean pinion angle is NO WHERE near correct for a CV; your pinion should be pointing directly at your d/s and it seems to me even on a stock non-lifted JL it's not even close to that.

I'd love to try a basic non-CV shaft up front but clearance at droop would be an issue for sure. I've also wondered if a basic spacer at the t-case flange might work? It's common on square body Chevys to clear the exhaust after a lift

Not at all, you need to use a double carden CV because of the angles. With a traditional driveshaft the yokes have to be on the same plane.

It's pretty much impossible to get a #1 or #2 solution on the front of the jeep. In the rear it's possible I guess but it will be harder to dial in for no real benefit.

And the stock pinion angles suck because they don't need to be good. Like I said before OEM rezeppa CVs don't care what angle they are at they will drive fine either way. They will just break eventually if it's too much angle for them.

 

[D60]

Not at all, you need to use a double carden CV because of the angles. With a traditional driveshaft the yokes have to be on the same plane.

It's pretty much impossible to get a #1 or #2 solution on the front of the jeep. In the rear it's possible I guess but it will be harder to dial in for no real benefit.

And the stock pinion angles suck because they don't need to be good. Like I said before OEM rezeppa CVs don't care what angle they are at they will drive fine either way. They will just break eventually if it's too much angle for them.

Yep, I need to get on level concrete and put an angle finder on the pinion flange but I bet it's really close to parallel w t-case flange, thus a non-CV d/s might have a shot. This is dead wrong angle for a CV, but to get it right for a CV I'd have horrendous neg caster

 

[JlRubicon13]

Will 8.5 degrees of caster cause damage to the driveshaft when fully flexed in 4low? Jeep has a 2 in spacer lift and drives much better than it did stock due to greater caster.

thanks

 

[Wabujitsu]

Update. 10,000 miles on my lift at this point, with some wheeling done over that time, disconnected sway bar, no extreme off-camber situations. We had my Jeep up on a lift a few weeks ago to find the source of a knocking noise at full lock, very slow speeds. One LCA needed one end re-torqued.

The boots and flanges are pristine; no tears, no bent flanges. I did measure the overall height gain that the 3.5” JKS lift gave my Sport. It’s at 5” over stock.

Sponsored