Neutral load driveline vibration

[WSS]

I’ve got a vibration that has started over the last 200-300 miles. I thought it was my tires but I swapped them out about 100 mikes ago and still the same. The vibration is at freeway speeds (or close to) and when in a neutral state, meaning no load. When accelerating, no vibration. When coasting down hill or even a slight load, no vibration. Just that sweet spot of “neutral” between load and coast.

I pulled the driveline yesterday to look for a bad joint or maybe a failed cardan union but everything looks good and feels tight. I am taking it over to JE Reel’s shop tomorrow for them to take a look.

Now, I’m running a 5.7 hemi-545rfe-4:1tc and Dana 60’s. The driveline is a Tom Woods and looks fairly low miles. I bought this JKU two years ago with 58k miles on it and now I’m at 63k. It is not really a daily driver but I do like driving it so it gets a fair amount of pavement time.

Any suggestions or advice?

 

[Mopar]

When you said pull the driveline, I assume you meant the front driveshaft? Did you drive it without the driveshaft while you had it off? If so, was the vibration still there?

 

[WSS]

When you said pull the driveline, I assume you meant the front driveshaft? Did you drive it without the driveshaft while you had it off? If so, was the vibration still there?

No, It was the rear that I pulled. I never thought of that. Good idea. It could be the front causing the problem, or the T case might be involved.

It is getting to a "critical" feeling in my head. It is probably nothing but the fact that it is new and increasing gives me that "better find it now" thinking.

 

[Mopar]

I’d bet on the front before the rear just due to the angles involved. Of course, I could be wrong too so gotta do some testing!

 

[WSS]

After some thought (mental thinking, really mental lol) I don't think the front driveshaft turns when the T case is in 2hi. But, I need to run it in 4hi and see if it does the same or if there is some change.

I did stop by JE Reel today and they looked at it and could not see or feel anything obvious. But they did not spin it. They will probably do that tomorrow. After a little education from them, I decided to go ahead have them make me a a fresh one. It will have a cardon that has 5 degrees more misalignment and .120 wall instead of .085 on the Tom Woods. It will use the same type of 1410 ujoints that are sealed too. The tube will be 2.5" instead of 3"

 

[Mopar]

I don’t know anything about your axles. If it was normal axles it would be spinning in 2wd.

 

[WSS]

Both front and back are Tera 60's w/ high pinion. The T case is a stock rubicon 4:1 ratio case. The T case shifts from 2hi to 4 hi and then to 4lo. From 4hi to 4lo, you have to be going slow, like 2mph to get it to shift. 2hi to 4hi can be done at speed.

This is the axle, they call the high pinion "CRD", which may be different from a true high pinion, but it looks higher than my typical D44:

https://teraflex.com/jk-67-crd60-hd-rear-axle-w-semi-float-5-38-r-p-arb-locker-4-6-lift.html

 

[Mopar]

I’m guessing it has manual hubs? If so then it’s probably not spinning in 2wd

 

[WSS]

I’m guessing it has manual hubs? If so then it’s probably not spinning in 2wd

Ahh, now I see what you mean. Ya it is spinning but with no input (no locking hubs). The vibration is definitely tied to the throttle input. A slight acceleration and the vibe goes away. Any downhill coasting and the vibe goes away.

 

[Mopar]

Ahh, now I see what you mean. Ya it is spinning but with no input (no locking hubs). The vibration is definitely tied to the throttle input. A slight acceleration and the vibe goes away. Any downhill coasting and the vibe goes away.

So it IS rotating in 2wd then. I don’t think it can be eliminated as an issue at this point . But, it’s easy to test. Take the front driveshaft off and drive it. If the vibration goes away it’s a front driveline issue. If not, it’s something else.

 

[WSS]

So it IS rotating in 2wd then. I don’t think it can be eliminated as an issue at this point . But, it’s easy to test. Take the front driveshaft off and drive it. If the vibration goes away it’s a front driveline issue. If not, it’s something else.

Good thought. I will pull it if the vibe is not cured with the new driveshaft. I see your point, I just misunderstood the process. It is age related.

 

[WSS]

I am going to go with "MOPAR" for the win.

I installed the new Reel rear drive shaft (very nice BTW) and was going to pull the front shaft to do the first test without the front in place and when I was removing it, I found some side to side movement, not worn needle bearings but lateral, the sound of the movement was near exact to the sound I was hearing, I swapped in a new 1350 non greasable and now it is tight and the vibe is 100% gone. Could it be the new rear, I doubt it (i needed a spare anyway, good excuse). The rear had no obvious "gotcha" like the front did. Damnedest thing.

 

[JeepJeezy]

I agree! I bought a 98 ZJ years ago from a dude who had a vibration issue. A shop told him it was his transmission. He didn't have the money to fix it, so I bought it for $300. The vibration was the front drive shaft. I had 1 laying around from an F-250. Threw it on and drove the ZJ for just over 4 years, then sold it for $2,200.

 

[Mopar]

That’s good news! Glad to hear it! The rear drive shaft is normally almost straight due to the angle of the engine, transmission, and transfer case. The front driveshaft has some serious angles that get worse with lift. I can’t say always but usually driveline vibrations involve the front end.

Any particular reason you replaced the rear driveshaft?

 

[WSS]

That’s good news! Glad to hear it! The rear drive shaft is normally almost straight due to the angle of the engine, transmission, and transfer case. The front driveshaft has some serious angles that get worse with lift. I can’t say always but usually driveline vibrations involve the front end.

Any particular reason you replaced the rear driveshaft?

Ya, I usually have a spare front and rear. This build is just taking longer. Now I have a spare rear that is in good to great shape. The new dl has 3 degree more pivot and 2.5” x .120” tube with no step up adapters. The tom woods is 3” x .085 or .090 wall tube on step up adapters with lots of weights tacked on. The reel has zero weights.

My front dl has a cardon too. I was surprised to see that. Luckily it was the u joint on the pinion that had the play.

 

[Mopar]

Ya, I usually have a spare front and rear. This build is just taking longer. Now I have a spare rear that is in good to great shape. The new dl has 3 degree more pivot and 2.5” x .120” tube with no step up adapters. The tom woods is 3” x .085 or .090 wall tube on step up adapters with lots of weights tacked on. The reel has zero weights.

My front dl has a cardon too. I was surprised to see that. Luckily it was the u joint on the pinion that had the play.

Gotcha. Just curious. I like to see what other people do and if I see a bunch of people doing something preventative, I start thinking I should consider that too. I love driving my Jeep but Jeeps aren’t that reliable. And, driving them in rough terrain really works the parts hard. I do preventative maintenance whenever possible and that ensures my Jeep is usually really for anything I decide to throw at it!!