Towing Vibration help needed

[TheNoachSHO]

So I have a weird one. The boat's in storage for now but spring is coming and I need to figure this out and hope someone out there has had a similar problem.

The boat trailer is a 2009 Karavan single axle that my 09 Bayliner 175 sits on. I tow it with my 05 Jeep Grand Cherokee 5.7 with the class IV hitch.

Completely randomly maybe 20% of the time at various stages of my 15 to 20 mile ride I will start getting a nasty vibration through the vehicle. The only way I can make it stop is by pulling over, shut the Jeep off and restart it. I'm really leaning toward a problem in the Jeep. However this ONLY happens when towing. I have never experienced it with the boat not hooked up, I have relatively low miles, 74k on it, the trans was serviced at 40k and I'm a huge maintenance ***** with making sure everything get's done. If it's not in the vehicle side the only thing I can imagine is that the bearings need to be replaced and they have wore a groove the races that completely stopping address's the problem.

I've greased them up to what I think is an adequate amount of times throughout the years but never pulled a wheel off or re-tourqed the bearings. I've owned it since new.

So what's everyone's opinions???

 

[wrench 3]

Re: Towing Vibration help needed

Would need a whole lot more information.
Do you have to shut off the engine or only stop the vehicle?
Does the vibration seem to come from the engine or the whole vehicle?
Is it affected by speed, power, turning or braking?
Do you have to drive for a while before it starts?
Does it shake the steering wheel side to side?

 

[TheNoachSHO]

Re: Towing Vibration help needed

Would need a whole lot more information.
Do you have to shut off the engine or only stop the vehicle?
Does the vibration seem to come from the engine or the whole vehicle?
Is it affected by speed, power, turning or braking?
Do you have to drive for a while before it starts?
Does it shake the steering wheel side to side?

Here goes....

1) Yes, shutting it off seems to help "cure" it.

2) Comes from the whole vehicle.

3) faster makes it worse, hoever, as I notice it starting it will increase harshness on it's own at a constant speed.

4) It's happened as soon as 4 miles away from the launch but then sometimes 20 or 30 miles away.

5) does not shake the steering wheel.

 

[LippCJ7]

Re: Towing Vibration help needed

tell us everything about the tow vehicle

 

[smokeonthewater]

Re: Towing Vibration help needed

if shutting off the engine really does help then it is certainly in the tow vehicle as shutting off the engine would have no effect on the trailer


Interestingly tho it is not uncommon for someone to set the parking brake on a ramp when they otherwise never use it and then forget to release it... sometimes they can cause a nasty vibration.

 

[H20Rat]

Re: Towing Vibration help needed

So one more question... So after it starts doing it, lets say you pull to the side/slow down, but don't turn off the engine. I'm betting it doesn't start acting up until you get up to a certain speed and it shifts into a certain gear?

 

[wrench 3]

Re: Towing Vibration help needed

Here goes....

1) Yes, shutting it off seems to help "cure" it.

2) Comes from the whole vehicle.

3) faster makes it worse, hoever, as I notice it starting it will increase harshness on it's own at a constant speed.

4) It's happened as soon as 4 miles away from the launch but then sometimes 20 or 30 miles away.

5) does not shake the steering wheel.

Still a little fogy on #1. If the "only" way to cure it is to shut of the engine, then you're re-booting the engine control module. However that doesn't add up with answers #2 & #3. Since the ECM only controls the engine and transmission. Also a rough running engine tends to smooth out the faster you spin it.
If the cure is from stopping the vehicle, that takes the load off of the drive line. A rough "U" joint some times can only be found by removing the shaft and flexing the joints. Also a vibration tends to build on itself. They may need a shake to get them started, so if you stop, it looses its catalyst. The change in load on the rear suspension may be affecting a rear wheel balance that doesn't show up without the trailer. Bad shock absorbers will also make a balance problem worse.
Since the drive shaft spins at about 3.5 times faster than the wheels, a problem there tends to give you more of a buzz, were the wheels give you more of a bounce.
I hope I haven't given you more questions than answers, but hopefully something in here helps.

 

[ken51k]

Re: Towing Vibration help needed

Try putting two or three hundred pounds in the very back of the Jeep (without the trailer) and take a ride to see if it does the same thing.

 

[jkust]

Re: Towing Vibration help needed

I've got a very similar issue with my snowmobile trailer. It vibrates starting at about 40mph for about a 5mph range then starts back up at about 60mph. Sometimes it does it and sometimes it doesn't. I bought it new in 08 and it sits 99.9999% of the time. If it is a tire situation, I'd expect more continuity. It has oil bath hubs so expect it isn't a bearing issue. I scratch my head like you when I tow it.

 

[wrench 3]

Re: Towing Vibration help needed

I've got a very similar issue with my snowmobile trailer. It vibrates starting at about 40mph for about a 5mph range then starts back up at about 60mph. Sometimes it does it and sometimes it doesn't. I bought it new in 08 and it sits 99.9999% of the time. If it is a tire situation, I'd expect more continuity. It has oil bath hubs so expect it isn't a bearing issue. I scratch my head like you when I tow it.

As I mentioned, vibrations tend to build on them selves. This causes them to resonate. As an example they may come in at 20mph, ease off and come back bad at 40mph, ease off again and come back at 60mph.

 

[dmoriarty51]

Re: Towing Vibration help needed

check out u joints and driveshaft.. I have encountered similar issues twice.

Twice on different vehicles we chased a vibe that would only start under a heavy foot or a load but once it started had to almost stop to cure it.

Once it ended up being a u joint. 1 cap at the rear diff end of it had rusted and turned the bearings to powder, the rest of the joint was fine. normal on vehicle shake and rattle test did not show issues we were down to doing ujoints just because to rule them out. This was on an 03 Dodge Dakota, the truck only had about 80k miles on it.

The other time the driveshaft had become twisted out of phase slightly, if you were really nice to the car you could run highway speed without the shake starting but under normal conditions that a high horsepower stick shifted car sees it would vibrate. This was in my 84 Firebird and they come from the factory with a very small diameter driveshaft and are notorious for this sort of vibration, the fix was a late model large diameter aluminum shaft.

Both these cases shook the vehicle rythmicly from one end to the other, the faster or heavier loaded you went the more violent it became.


EDIT. One other instance that i just remember was in a 2000 f 350 diesel, the pilot bearing in the clutch destroyed itself. This cause a full vehicle vibration only noticed when loaded, we surmised under no load you let the clutch out quickly and everything stayed centered. When loaded often 10k lbs or more you slipped it a little and without proper support the input shaft walked a little causing the vibration

 

[dmoriarty51]

Re: Towing Vibration help needed

I've got a very similar issue with my snowmobile trailer. It vibrates starting at about 40mph for about a 5mph range then starts back up at about 60mph. Sometimes it does it and sometimes it doesn't. I bought it new in 08 and it sits 99.9999% of the time. If it is a tire situation, I'd expect more continuity. It has oil bath hubs so expect it isn't a bearing issue. I scratch my head like you when I tow it.

Thats classic tire vibration based on what my elders taught me.

 

[MH Hawker]

Re: Towing Vibration help needed

Hubs going bad or tires need balancing.

 

[H20Rat]

Re: Towing Vibration help needed

Still a little fogy on #1. If the "only" way to cure it is to shut of the engine, then you're re-booting the engine control module. However that doesn't add up with answers #2 & #3. Since the ECM only controls the engine and transmission.

It is a reach, but there IS a potential ECU related cause... Faulty traction control systems can cause this, it might be pulsing the brakes or locking up a diff. That is why I asked if it goes away if you come to a stop but don't shut down. If the problem does NOT go away, I'd highly suspect it is directly related to one of the 2 reasons above. (and yes, traction/engine control systems can have different programs to run if you are towing. Some will guess it based on load, some actually have sensors in the hitch)

 

[Redfred1]

Re: Towing Vibration help needed

Check the fan clutch; it can give some weird symptoms and noises. Also; if possible; drag a different trailer; it will eliminate yours. Like everybody else; just guessing. Good luck. RF

 

[phillyg]

Re: Towing Vibration help needed

I think unrelated to the tow vehicle. I'm guessing one of the trailer tires is out of balance and some sort of vibration occurs under certain circumstances. I know a lot of folks don't balance their trailer tires, but I've seen a few trailers on the highway with a wheel or two jumping up and down as it goes round and round.

 

[TheNoachSHO]

Re: Towing Vibration help needed

So one more question... So after it starts doing it, lets say you pull to the side/slow down, but don't turn off the engine. I'm betting it doesn't start acting up until you get up to a certain speed and it shifts into a certain gear?

No, it's usually vibrating right away.

Still a little fogy on #1. If the "only" way to cure it is to shut of the engine, then you're re-booting the engine control module. However that doesn't add up with answers #2 & #3. Since the ECM only controls the engine and transmission. Also a rough running engine tends to smooth out the faster you spin it.
If the cure is from stopping the vehicle, that takes the load off of the drive line. A rough "U" joint some times can only be found by removing the shaft and flexing the joints. Also a vibration tends to build on itself. They may need a shake to get them started, so if you stop, it looses its catalyst. The change in load on the rear suspension may be affecting a rear wheel balance that doesn't show up without the trailer. Bad shock absorbers will also make a balance problem worse.
Since the drive shaft spins at about 3.5 times faster than the wheels, a problem there tends to give you more of a buzz, were the wheels give you more of a bounce.
I hope I haven't given you more questions than answers, but hopefully something in here helps.

The ECM is my biggest concern. However it's interesting that you bring up the u-joints. The rear driveshaft is actually new with only about 15k miles but the front I did just replace the CV joint at the transfer case for a vibration issue at 75mph. I also had to put a new solenoid on my front differential for the locker. This was all done after the boating season. I'm really hoping that this will solve it and am happy people are point to u-joints.

I'm def going to check the trailer tires and bearing once it's out of storage. Thanks for the replies and i'll be sure to update everyone come april/may.

 

[gtochris]

Re: Towing Vibration help needed

Could it be the torque converter locking up? Have you tried downshifting manual to 4th gear when this happens ever?

 

[reelfishin]

Re: Towing Vibration help needed

I had an older Jeep that did about the same thing. At about 80,000 miles or so it started to get a vibration under light load when towing. What it turned out to be is a slight engine miss, that turned out to be a weak #6 cylinder compounded by a sticking or sluggish to disengage torque converter clutch. It would start to miss and vibrate under light load then get worse if you pushed it. If I pulled the trans down into a lower gear and drove harder, it often never happened. The fix was eventually a trans overhaul with a heavier duty torque converter and at 99K, a new engine when cylinder #6 tested at only 35 psi of compression.

On another trailer, just last spring, on a small trailer with 8" wheels, when towed 90% of the time it was fine, but every so often, usually just after making a turn, it would begin to vibrate at highway speeds, and get worse with more speed. The hubs, bearings, ad springs were all new. The tires were four years old. In an attempt to balance the trailer tires I mounted them on a spin balancer and found both tires were within a 1/4 oz. of being perfect. That was on a hand spun wheel balancer. After not finding the problem, and the fact that it didn't matter which tow vehicle I was using, I mounted the rear tires u on a lathe at work and spun them faster, what I found is that both rear tires would 'grow' at speed and get slightly out of round toward the valve stem side. I swapped the tires with an old utility trailer and the vibration was gone. The bad tires weren't old or cracked and never vibrated on the utility trailer which is a bit heavier. The boat trailer never has more than a couple hundred pounds on the tires.

 

[Scott Danforth]

Re: Towing Vibration help needed

First thought - original plugs?

I have had vehicles that start to miss slightly under load when the plugs get long in the tooth. shutting off and restarting was a symptom. However it usually thru a code and set off the CEL.

Second thought - Multi-displacment system having issues when towing.