Aftermarket Driveshafts

[Keithbickford]

It is the 1350 shaft. Unfortunately with these stock axles there’s no way to get the pinion angle correct with as much caster as we had it set to.

I just found this old thread when searching for my own issue. From what I’ve researched, pinion angle shouldn’t be an issue with the double cardan driveshaft. Curious if you’ve resolved this.

 

[Keithbickford]

It will fail. It will bind at transfer case pinching rubber seal it will start to leak. Then game over it might last for months but it’s just a matter of time. Also I would recommend 1350 ujoints I have seen 1310 joints fail on a Jeep in our club. It failed on a simple hill climb. Tom Woods will only build 1350 joints for the 392 . I am talking about the front driveshaft . The stock rear driveshaft should be fine many have replaced the rear .This is what I have observed .

Nailed it. I’ve been chasing a vibration and just noticed torn rubber inside the CV flange on the transfer case side.

 

[2024White392]

I just added the FAD to Aux 3 switch and while I was at it did RCV axle upgrade. I was having a decent amount of driveline vibes. Now have 2 wheel drive as auto, so front axle only engages when I turn aux 3 on. Also got an alignment afterward and I think they jacked up the rear pinion angle because I still have vibes when in 2 wheel drive mode. Chasing the vibes since the lift and going to 1350’s front and back has been very frustrating.

 

[Keithbickford]

good solutions. Regarding rear pinion angle, the alignment shop shouldn’t be touching that. Only adjustable rear track bar to center the axle left to right.

 

[2024White392]

Ok but what about rear upper and lower control arms? Adjusting those changes rear pinion angle.

 

[Earl 392]

good solutions. Regarding rear pinion angle, the alignment shop shouldn’t be touching that. Only adjustable rear track bar to center the axle left to right.

adjustable CA’s

 

[Keithbickford]

That’s true, but it’s not common for an alignment shop to even look at something like that.

 

[2024White392]

My receipt says “4-wheel alignment.” I presumed that would include rear end. When the rear end is all adjustable seems like they should but maybe they are used to stock which would allow no adjustment in rear?

 

[Keithbickford]

Yeah, the effort to adjust control arms is far beyond the alignment shops. Also, their scope is clear. Adjust to obtain, track, caster, camber, and toe. None of which involve adjusting rear control arms. Even front would be a stretch with a solid axle vehicle that doesn’t normally have adjustable control arms. They have to be unbolted to adjust. That’s a lot of work. I adjusted my fronts today. Pain in the ass.
If you find a shop willing to try, you’re partially lucky. You may have to train them. But if you can, your Jeep will be happy.

 

[Keithbickford]

This is what happens when you run Fox 2.5 DSC shocks meant for 3.5” lift. Not the shocks fault.

 

[2024White392]

Yeah, the effort I adjust control arms is far beyond the alignment shops. Also, their scope is clear. Adjust to obtain, track, caster, camber, and toe. None of which involve adjusting rear control arms. Even front would be a stretch with a solid axle vehicle that doesn’t normally have adjustable control arms. They have to be unbolted to adjust. That’s a lot of work. I adjusted my fronts today. Pain in the ass.
If you find a shop willing to try, you’re partially lucky. You may have to train them. But if you can, your Jeep will be happy.

Right, so how do you find one of those shops!? Or I guess rear pinion and alignment I could learn to do in my home garage myself?

 

[Keithbickford]

Right, so how do you find one of those shops!? Or I guess rear pinion and alignment I could learn to do in my home garage myself?

The importance of pinion angle and driveline working angle is critical for drive lines that contain U joints. The 392 rear driveshaft does not contain U joints. Instead it uses RZEPPA CV joints at both ends. So there’s no vibration concern on the rear driveshaft. unless it’s bent or unbalanced from the factory. Pinion angle is also not critical. Clayton Off-road has recommended control arm lengths published on their install instructions. They say they are just a starting point. But for the rear, they should be adequate. If it was mine, I’d look at their recommendations and set the lengths to that.
I discovered by front driveshaft CV was trashed and causing vibration. I ordered a Teraflex high angle CV joint, but it appears to be identical to OEM. I will call Adams driveline on Tuesday to discuss with them.
My end solution will likely be to add a custom Adams driveshaft.
Have you inspected your front CV?

 

[2024White392]

The importance of pinion angle and driveline working angle is critical for drive lines that contain U joints. The 392 rear driveshaft does not contain U joints. Instead it uses RZEPPA CV joints at both ends. So there’s no vibration concern on the rear driveshaft. unless it’s bent or unbalanced from the factory. Pinion angle is also not critical. Clayton Off-road has recommended control arm lengths published on their install instructions. They say they are just a starting point. But for the rear, they should be adequate. If it was mine, I’d look at their recommendations and set the lengths to that.
I discovered by front driveshaft CV was trashed and causing vibration. I ordered a Teraflex high angle CV joint, but it appears to be identical to OEM. I will call Adams driveline on Tuesday to discuss with them.
My end solution will likely be to add a custom Adams driveshaft.
Have you inspected your front CV?

I am Running aftermarket 1350 driveshafts that are brand new.

 

[Keithbickford]

I am Running aftermarket 1350 driveshafts that are brand new.

Gotcha. Then all I said doesn’t apply in this case. Many people get stuck on pinion angle. Nevermind that. You want to determine the working angles of both u-joints, and adjust the control arms to make them the same.
1. Measure the transfer case output, and the driveline angle. The difference is the working angle.
2. Do the same on the differential end.
3. Adjust rear upper control arms so that both working angles are the same.

Or the simpler way to do, this is just to measure the angle of the transfer case yoke and adjust the upper control arms so the pinion yoke is at the same angle and parallel to the t case yoke.

There are some good videos on this topic. But many are wrong. Look for some of the videos from Adam’s and other reputable manufacturers.

 

[prodriquez]

That’s true, but it’s not common for an alignment shop to even look at something like that.

I’d never trust a regular alignment shop with a lifted jeep… there are simply too many things going on for them to handle

I highly recommend that lifted jeep owners take their jeep to a reputable off-road shop that also does alignments. I’ve done this with a few MC lifts, which can easily be installed in your driveway.

It will obviously cost more… but they know what they’re doing and they can get it dialed in.

 

[prodriquez]

This is what happens when you run Fox 2.5 DSC shocks meant for 3.5” lift. Not the shocks fault.

For those that don’t know, most (if not all) +3.5” lifts require a new front driveshaft and an extended-travel shock may require new front and rear driveshaft and/or limiting straps, regardless the lift height.

Based on the pic, I’m assuming this is a front driveshaft and you were running a shock that was specked for a bigger lift?

If the answer is ‘yes’… don’t forget to check your clearance, at full droop, because the added down travel may exceed the limits of your other suspension components. Bent or slipped driveshafts, bent end links, or individual springs popping out from their perches are the most common things I’ve seen on the trail.

Heck, even when taking the necessary precautions… stuff happens on the trail that can’t be checked in the shop and sometimes stuff just breaks.

In my own case, I run King coilovers and I’ve bent a front end link over my tie rod while going over something I should have gone around, ruined a new set of AAL rear inner fender liners on my rear Antirock that I thought would clear, and snapped my front locker line going off a drop no one else would do... It’s just part of the game

 

[Keithbickford]

For those that don’t know, most (if not all) +3.5” lifts require a new front driveshaft and an extended-travel shock may require new front and rear driveshaft and/or limiting straps, regardless the lift height.

Based on the pic, I’m assuming this is a front driveshaft and you were running a shock that was specked for a bigger lift?

If the answer is ‘yes’… don’t forget to check your clearance, at full droop, because the added down travel may exceed the limits of your other suspension components. Bent or slipped driveshafts, bent end links, or individual springs popping out from their perches are the most common things I’ve seen on the trail.

Heck, even when taking the necessary precautions… stuff happens on the trail that can’t be checked in the shop and sometimes stuff just breaks.

In my own case, I run King coilovers and I’ve bent a front end link over my tie rod while going over something I should have gone around, ruined a new set of AAL rear inner fender liners on my rear Antirock that I thought would clear, and snapped my front locker line going off a drop no one else would do... It’s just part of the game

Yep, front. I have anti-rock sway bars. Springs are good. I had to modify brake line routing, and e-brake cable routing. Rear driveline looks great at full droop. T-case and diff angles also help. I’m at stock angles.
On the front, the t-case angle is not helpful, and diff angle is also limited by caster. I’m at 4.5° caster and it feels fine.
I do have very slight driveline vibration with the new Adams front shaft. To be expected.

 

[Earl 392]

Yep, front. I have anti-rock sway bars. Springs are good. I had to modify brake line routing, and e-brake cable routing. Rear driveline looks great at full droop. T-case and diff angles also help. I’m at stock angles.
On the front, the t-case angle is not helpful, and diff angle is also limited by caster. I’m at 4.5° caster and it feels fine.
I do have very slight driveline vibration with the new Adams front shaft. To be expected.

This bracket is great works perfectly

 

[355spider]

I just added the FAD to Aux 3 switch and while I was at it did RCV axle upgrade. I was having a decent amount of driveline vibes. Now have 2 wheel drive as auto, so front axle only engages when I turn aux 3 on. Also got an alignment afterward and I think they jacked up the rear pinion angle because I still have vibes when in 2 wheel drive mode. Chasing the vibes since the lift and going to 1350’s front and back has been very frustrating.

How did you get 2 and 4 wheel drive set to your aux?