Driveshaft Run Out

[Intense-Dakota]

I have been chasing a vibration for years at 50 mph, and then it gets worse around 65-70. Tire balances have always come back as below 14lbs of road force. Well, I wonder if I found the issue.

After replacing my ujoints on my 2017 Rebel rear driveshaft, I checked for runout and noticed the following.

Front at trans 0.004 in run out
Rear at diff... 12 & 6 o'clock position are 0.000 and 3 & 9 o'clock are 0.030 & 0.035 (slightly oblong but balanced at center within 0.005 inch.
Rear pinion side ujoints 0.000 run out.

Other than the oblong shaft, they seem good, right?

Move to center of shaft. Through the shaft, I get 0.000 on 12 o'clock and between 0.025 and 0.040. so, it appears the shaft is slightly bent or possibly out of round.

What is everyone's thoughts on this? Do I spend $1-200 to balance existing or $6-700 to replace with OEM, or does anyone know a good aftermarket that still uses good ujoints? Or, is this (out of spec) driveshaft still not bad enough to cause a vibration?

Appreciate any thoughts.

 

[Bigskyroadglide]

I replace it with an aftermarket one. My aftermarket driveshaft is awesome and has provided solid service for 50 k at all speeds

 

[Intense-Dakota]

Do you have a recommendation on a site or brand?

 

[Wild one]

Do you have a recommendation on a site or brand?

The regular cab shortbox 8 speed trucks are easy to get driveshafts for,your truck not so much,you'll have to have it custom built,and hang onto your shorts as it's gonna be s'pensive.If you got a driveline shop with-in driving distance,you'd probably be better off having them balance it and straighten it if it needs straightening

 

[Intense-Dakota]

Few local shops have them for $4-600, and OEM I can get for about $750. Those are within reason but if there's better, I'm willing to spend on it.

 

[Wild one]

Few local shops have them for $4-600, and OEM I can get for about $750. Those are within reason but if there's better, I'm willing to spend on it.

I think your truck is the 1 piece rear shaft,if it is,it's fairly s'pensive.

https://store.mopar.com/oem-parts/mopar-drive-shaft-52123830ab?c=Zz1yZWFyLWF4bGUtY29ycG9yYXRlLTIzNS1tbS1kaWZmZXJlbnRpYWwtYW5kLWRyaXZlLWxpbmUmcz1kcml2ZS1zaGFmdCZsPTEmbj1Bc3NlbWJsaWVzIFBhZ2UmYT1yYW0mbz0xNTAwJnk9MjAxNyZ0PXNsdCZlPTMtNmwtdjYtZmxleA%3D%3D

 

[Intense-Dakota]

That's the 6 speed but yes from Ma Mopar, its $1100, but from all the Mopar stores it's about $400 off.

 

[Wild one]

That's the 6 speed but yes from Ma Mopar, its $1100, but from all the Mopar stores it's about $400 off.

Look again,at the fitment chart,it's for the 8 speeds as they never put a 3.6 in a Ram with a 6 speed,and even in Canada they'd dropped the 6 speed by 2020.
Hit up Benny ,he's a vendor on here and is usually very competitive on pricing,plus he'll know what shaft you need

All Mopar Parts​

All Mopar Parts

Offering Genuine Mopar Ram Parts & Accessories at discounted prices! www.allmoparparts.com

www.ramforum.com

 

[Intense-Dakota]

I did look again, and it still says "Notes:Transmissions: 6-SPD AUTOMATIC 65RFE TRANSMISSION.". I am not here to have an internet argument about who's right. I asked for suggestions, and appreciate feedback, but I didn't make the part so I just go by what's written. Thanks for your comment and I'll keep looking.

 

[Wild one]

I did look again, and it still says "Notes:Transmissions: 6-SPD AUTOMATIC 65RFE TRANSMISSION.". I am not here to have an internet argument about who's right. I asked for suggestions, and appreciate feedback, but I didn't make the part so I just go by what's written. Thanks for your comment and I'll keep looking.

Yea that sites a bit f l u c k e d up,as it says it's for the 6 speed,but if you go by the fitment chart,nothing on the fitment chart has a 6 speed in it. Hit up Benny he'll know what you need,and he'll usually match most online retailers

 

[Jeepwalker]

I doubt that low amt of D/S run-out is the issue. That's why they balance them (are the weights still there)? Did you 'relieve' the U-joints after you installed them?

I would go back to your trk's wheels. That's a low road-force score. Which is good ...you've kind of ruled out the balance. I would suggest checking the tire surface again (carefully) with your hands to make sure since then there are no tire surface abnormalities. Have you checked your trk's hubs and axle flange? Have you jacked the truck up (on jackstands) and put in gear (safely) to watch the tires/wheels? I would say, if you haven't consider doing so. Maybe even put your gauge on them.

Two things to consider:

Relatable story #1: I bought an OReilly's front hub a few yrs back for my H3. Their better one in stock whatever they call it. I checked run-out ...out of the box in my vise. It looked decent but not as good as OEM hubs I've installed in the past. And being from OReilly's, I checked it. Low and behold, it had .005" deflection at the hub-face. That's obscene! That would have translated into a lot of wobble at the outer edge of the 33" tire!! No repair shop is going to check a new hub out of the box ...so you never know. I marked it defective with a paint pen and took it back. Who knows they might have cleaned it off with carb cleaner and resold it. I Bought a Delco USA-made replacement from R Auto which looked 3x better & had zero deflection.

Also, I own a solid-axle jeep which I bought used some yrs ago. It also had a vibration since day-one (in my ownership) and the brakes would pulse like a bad rotor. Checking rotor run-out one day I determined the real issue was a warped hub-face. Replaced 5yrs ago and she's smooth as butter since! So...it does happen, probably more often than we know.

Story #2: I collected 6 identical aluminum Corvette C3 wheels... a couple at a time over yrs at swap meets etc as I ran across them. They looked good. The idea being I would polish them up and put on next time it needed tires. Well, the day came I was going to start polishing so I chucked the C3 spindle in the vise and checked one of the wheels before I put work into it. BTW I had trued the hub-face to zero run-out...so that's good. Well, Dang if it didn't have a lot of run-out by eye. So I checked the next ...then the next. Now, I've polished up several sets of aluminum wheels over the yrs, and none of these wheels appeared to be beat-up, corroded or had been polished in the past. I thought it would be an easy resto. Turns out all 6 of those aluminum wheels were 'off' or had what I deemed a fairly significant amt of run-out than I wanted. It would have for-sure caused the car to shimmy some going down the road, which is exactly what I DIDN'T want. So, I abandoned that idea and bought a brand new set of C/A (Chinese) re-pops. They look fantastic. I checked them the same way, same spindle.... zero run-out at all!

So..... the point is, there's always the possibility of a warped wheel or axle/hub flange. I would definitely rule that out. Even if they were Road-Force balanced, I've stood right there many times and the vast majority of tire guys will short-cut the process. A wheel could still be slightly off.

I would put it up on jackstands and (safely) double-check wheel run-out. And if you find any, investigate the hub face.

 

[Jeepwalker]

Have you looked into the shocks?

Another possibility is worn shocks allowing the tire to 'hop' a bit. A shock can be overall 'good' and ride nice over bumps and dips in the road, etc. However, they can sometimes develop a condition where the rod can be loose in that 1/2" or 1" of travel where the vehicle normally rides. I've seen it a number of times. And if you stroke the rod quite a bit, it becomes stiff in it's center travel. But if you wait... the oil will normalize out and the rod will get loose again for that 1/2" - 1" of center travel. If a guy was going down a smooth highway with such a shock, that could lead to the tire suddenly starting to hop around a bit. And you'd feel vibration.

If that happens a tire can start to hop when it hits bumps or tar strips, etc. If the wheels are for sure 'true' and the hubs are 'true' ...shocks are another thing to look into. Esp if you see any oil on a shock. But if you can ID which wheel has the shimmy, maybe remove ...and test it, or just replace it. If you can feel it in the steering it's probably the front wheels. If not, then probably the rear. And also, sometimes the shock's rubber bushings can wear out and gain some 'freeplay' in them which a guy might or might not easily see. These things kind of need to be checked out by eye and hand, the old fashioned way.

Let us know what the ultimate issues is.

 

[Intense-Dakota]

Thanks. I did check all joints and they did move freely with no stiffness or binding throughout the movement. I have not checked the rear hubs themselves yet (more later). I have replaced every other part (front and rear) as I just converted from air to spring and decided a full refresh was in order at a little over 110K miles included ng front hubs and all brake components as rear were only 2nd set from OE. I will say the wheels do spring true (off the ground) and when tested there was less than .002-.003 in runout at the outer edge of the rims stock Rebel rims. I have checked the tread for anomalies also using a thin feeler gauge clamped on end and set about 1/16 inch off the tread and when watching visually. I know it's not super scientific but the gap across all wheel sections where very close if not exact. These are Toyo Open Country AT3 in original size also. OE were AT2's.

I found a local off-road shop and I am going to have them check, straighten and/or rebalance the DS. The weights appear all to still be there and I've never smacked it during off-road adventures, so it may be a waste, but at least piece of mind.

I may take the truck to a different shop and ask to have the wheels removed, rotated and rebalanced even though in 15K miles the vibration hasn't changed at all.

The last thing I can think of was rear diff, but I had dealer check it when they replaced the fluid a few months back and said everything looked good as new.

 

[Intense-Dakota]

Have you looked into the shocks?

Another possibility is worn shocks allowing the tire to 'hop' a bit. A shock can be overall 'good' and ride nice over bumps and dips in the road, etc. However, they can sometimes develop a condition where the rod can be loose in that 1/2" or 1" of travel where the vehicle normally rides. I've seen it a number of times. And if you stroke the rod quite a bit, it becomes stiff in it's center trave. But if you wait... the oil will normalize out and the rod will get loose again for that 1/2" - 1" of center travel.

If that happens a tire can start to hop when it hits bumps or tar strips, etc. If the wheels are for sure 'true' and the hubs are 'true' ...shocks are another thing to look into. Esp if you see any oil on a shock. But if you can ID which wheel has the shimmy, maybe remove ...and test it, or just replace it. And also, sometimes the shock's rubber bushings can wear out and gain some 'freeplay' in them.

Let us know what the ultimate issues is.

Yes, prior shocks were changed from OE to Fox 2.0 and again recently to Eibach Pro.

 

[Jeepwalker]

Ok...sounds like you checked those things pretty well.

Have you noticed much/any meaningful drive shaft freeplay where the yoke enters the xfer case? Like worn splines? You'd have to raise one rear wheel to unload the drivetrain to check that.

Front half shafts are fairly tight?? Has anyone checked the axle disconnect on the front R side? IDK to what extent that would cause vibration. But watch a couple videos on that.

 

[Jeepwalker]

It'll be interesting to see what they say about the D/S. I've had a couple balanced way back in the old days. You'll find out if it's good or at least rule it out.

 

[Sherman Bird]

I have been chasing a vibration for years at 50 mph, and then it gets worse around 65-70. Tire balances have always come back as below 14lbs of road force. Well, I wonder if I found the issue.

After replacing my ujoints on my 2017 Rebel rear driveshaft, I checked for runout and noticed the following.

Front at trans 0.004 in run out
Rear at diff... 12 & 6 o'clock position are 0.000 and 3 & 9 o'clock are 0.030 & 0.035 (slightly oblong but balanced at center within 0.005 inch.
Rear pinion side ujoints 0.000 run out.

Other than the oblong shaft, they seem good, right?

Move to center of shaft. Through the shaft, I get 0.000 on 12 o'clock and between 0.025 and 0.040. so, it appears the shaft is slightly bent or possibly out of round.

What is everyone's thoughts on this? Do I spend $1-200 to balance existing or $6-700 to replace with OEM, or does anyone know a good aftermarket that still uses good ujoints? Or, is this (out of spec) driveshaft still not bad enough to cause a vibration?

Appreciate any thoughts.

Here in my neighborhood, we have Northwest Driveline services, and downtown, we have Heitman and Sons. I've use them both over the span of my 49 year career and had great luck with them both.

They have been especially good to have when a driveshaft gets to the near-$1000.00 mark, being their services are a fraction of that. I wonder what resources you might have available to you in your locale.

 

[Intense-Dakota]

Ok...sounds like you checked those things pretty well.

Have you noticed much/any meaningful drive shaft freeplay where the yoke enters the xfer case? Like worn splines? You'd have to raise one rear wheel to unload the drivetrain to check that.

Front half shafts are fairly tight?? Has anyone checked the axle disconnect on the front R side? IDK to what extent that would cause vibration. But watch a couple videos on that.

The only play really at all is in the front CV shafts at on the diff side. When I had fron fluid changed (few months back) the dealership said it should have some play and that it was normal. I have contemplated replacing the front CV and intermediate but can't justify it just yet as everyone said they are fine. On the rear side, TC to front and rear drive shaft have no measurable slop. I have not removed front DS but that is next on the list. I don't notice any change in 4x2 or 4x4 lock regarding the vibration or anything else