Hello forum members, I have been doing pretty good keeping Jor's old 34' going down the road. This is out of my knowledge though. I will post pics, I think I have that part figured out. We are at Enid Lake Mississippi. Very nice Corps. campground. Yesterday driving we started hearing some thunking, I just thought something was rolling around thumping in a cabinet. It got worse, wife says coming from underneath. It does seem to thump letting up, and then pressing down throttle pedal. Which I would imagine, could be what I am seeing in pics.
We were headed to Biloxi, but thinking at the every least we should head back towards home, which is about 600 miles to Missouri. Any knowledge and help would be much appreciated. Kim and Elana McCoy
So Kim in your first photo you are pointing out the driveline slip yoke. With it raised it is normal to see a shiny metal. Mine also has a layer of grease on it from over servicing both it and the joint about every 7K miles. To the left of the picture on that same shaft is a big round metal disk just past the rear U joint. I would take a prybar and side load it and see if there is any free movement side to side and up and down. Since you say you have a 34 foot coach Im guessing it is a 270 coach with a 8.3L engine and a 3060 Alison transmission. They are problematic for having the dampeners coming loose. Free play will indicate this as I understand
Scott
Thanks Scott, I haven't figured out how to put coach info, on my profile. 97 270 34' 8.3 mechanical. I will see what happens when I do as advised, and post outcome. Kim
Yup, exposed shiny metal normal-- it extends/contracts to account for movement between axle and chassis.
Check both U joints as well as transmission dampner.
Looks like drive line could use a bit of grease also.
"Thunking" is such a vague description. Do you hear a thunk once upon changing direction? Say when you go from coasting to accelerating? One thunk is okay. Steady vibration deserves some observation and analysis.
The shiny area your yellow arrow points to is the drive spline in its extended position. That's a part that's often overlooked when running around with the grease gun, because if it doesn't have a grease fitting of some sort it needs to be pulled apart to be re-greased. If there is a problem with the drive shaft as others have said you can grab it in you hands and move it. If it doesn't move, no problem.
One thunk? Keep driving.
I can turn dampener and u joints slightly left and right. When I turn forward facing u joint, on rear end side, slightly to the left and then clockwise I can here a clunk?? Seems to be inside housing, normal?? will post pic. Not sure where to pry on the dampener. Anyone have a pic? So use a steel bar? Thanks for all the reply's!!
The damper does'nt come loose, the bearing in the trans housing does and may need to be tightened and or replaced,had mine
repaired in Memphis at a very good shop,there is an elbow towards the bottom of the trans under the damper,you can gently put the pry bar there and check end play,grease the u joints and shaft and see if that helps with the clunk,make sure the trans fluid is topped off.
Every Foretravel driveshaft I have worked on/inspected DID have a (one) grease zirk on the spline and two on the U joints. Grease either of the U joint zirks, as both are drilled to the same center of the cross.
That would be the gear backlash and normal doing what you describe. The bearing Scott talks about is at the other end of the driveshaft and in the tailshaft of the transmission. You need to find a place to pry that damper sideways or up and down.
As I recall from earlier threads, if the transmission dampner needs replacing, several have used the Allison shop in Longview, TX.
Also make sure your differential lube is topped off.
Sales + Service Locator (http://www.allisontransmission.com/sales-service-locator)
Stewart & Stevenson Power Products, LLC
4935 Whitehurst Drive
Longview, TX 75602
903-758-5562
Of course pry bar is one thing I don't have, and grease gun LOL. I do have this, just don't have any idea how much muscle to use. Is this where to try for movement?
Yes see if there is play there. It should not move.
That would be the pinion bearing and if it were problematic you could wiggle the drive shaft up and down. Turning from one side to the other is the backlash between the pinion and the ring gear, and not to belittle your concerns, but I'm wondering if what you're hearing is normal. Sometimes as we become used to a new machine, as we become comfortable in its operation we begin to notice "new" noises and vibrations. These were always present but buried under the noise of all the new sensations that come with new machinery.
Now the output bearing on the automatic transmission, if you can find movement there, you have something to be professionally addressed sooner rather than later.
I leaned on it pretty good, I am not getting any movement. I will check tranny fluid, stop somewhere buy grease and gun, which I was wanting something better anyway, see what happens I guess. Any more words of wisdom, please share, I appreciate it very much. Thanks
I have put about 4 thousand miles on the coach, we haven't heard this before, it is pretty distinct. No movement on the dampner that I can produce. The dampner and yokes will slightly turn counter clockwise and clockwise. Thanks Kim
I will see if I can move shaft up and down.
I can maybe very very little move shaft slightly up and down. I just realized, I bought a pair of overalls for this occasion, now that I have my clothes all full of grease. Par for the course.
Transmission Dampener (https://www.foreforums.com/index.php?topic=8387.0)
Barry seems to have a real good handle and understanding of this since he has been threw it. Would certainly think if it has been repaired or had the upgraded parts installed it should be with the prior records. Allison may even have history if they did the repair. I just reread the post and they go into good detail about it. You say that you think that there may be some play in it, I personally would want to get in front of it before it does any damage. Sounds like they changed the bolts and doubled the torque requirements on them to prevent. 4060 trans doesn't have these issues and was a contributing factor to wanting a 4060 rather than a early 3060 for me. Regardless if you don't know it's repair status it may be worth looking into farther. Please keep us updated.
Scott 🤞
Ken, I would recommend buying a grease gun with a pistol grip pump--you can hold the hose on the grease fitting with one hand and pump with the other
Just my thought
Chris
I can recommend the "Lock N Load" grease gun with an accessory easy lock coupler. Bought grease gun at Tractor Supply and it is designed to self bleed the air when changing over grease cartridges.
LockNLube Grease Gun Coupler locks onto Zerk fittings. Grease goes in, not on the machine. World's best-selling original locking grease coupler. Rated 10,000 PSI. Long-lasting rebuildable tool. Amazon.com: LockNLube Grease Gun Coupler locks onto Zerk fittings. Grease... (https://a.co/d/hNxPFFL)
These two are worth the money in my experience.
Some other possibilities that can cause a thump to occur.
Does this happen in third gear? with the 3060 it could be a shift solenoid.
Check your motor mounts, epically the rear.
Look at your trailing arms for a broken bolt.
Have you recently had the wheels off? With your coach being a '97 you should have Budd wheels check torque on lug nuts. They changed to metric wheels on coaches between 5209 and 5212
Feeding the grease worms like have been touched on is a good start.
Mike
Another diagnostic/repair option would be a visit to American Shifty co. in North Little Rock. Others have had driveline issues addressed there, including the dampener and been pleased with the service. . Its kinda on your way home.
I had a very heavy thumping noise on my 95 U320 when I would accelerate hard, then brake, then accelerate again.
I found it to be the rear bulkhead had enough play from the bolts rusting out that it was slapping and pounding the rear angle iron.
I cleaned it, cut away the fiberglass belly about a foot in front and cleaned out the rust, painted, and drilled through for new SS bolts . End of problem.
Check your FRONT and REAR bulkheads. If you see some cracking in the side wall of the coach down around where the bulkheads are, you might see the problem if that is YOUR problem.
A bad or loose shock can make a crazy knocking sound too.
Mine did that. Thought it was u joint. Sounded like running on rumble strip but not quite as loud. Turns out slide pin seized on passenger rear disc brake. Melted disc and rotor. Only noise when letting off and accelerating. No fun. Expensive lessons
Kim,
Suspect you have concluded from the number of different things that can cause your noise that you HAVE TO determine the cause before driving very far.
Transmission and rear axle are the same (though in "backwards") as many trucks. The air disk brakes are found on many fire trucks. So, you should be able to find a HD truck mechanic to give it a quick look "under" to rule in/out the root cause.
Good morning, we went to tractor supply in Batesville. Bought a lock n load grease gun, which is nice. Hit the drive shaft and u joints, no change in noise. Elana has termed it knocking, and says it sounds like it is coming from below floor in front of fridge. I have checked bulkheads everything looks good, has been repaired. Nothing that I can see with brakes. We are getting some oil around rear wheel outside dually (axle seal?) I have a shop near home, that I trust, would like to get there. Thanks
Also checked shock bolts all good.
Dose the knock increase with RPM and /or road speed,any chance of recording sound and sending it to one of our phones.
It seems to be more of a suspension problem then driveline, but who knows. Kim
That's funny, I was telling Elana around the campfire last night, that we should make a recording. Post it and call it Name the Thump.
It doesn't do it shifting gears, or downshifting, or retarder use or braking. It will knock more like, in just the movement of slowing or increasing speed. Honestly, to me it sounds more like an old house settling on its foundation.
Could be one of your torque rods bolt broke but unlikely,you can take a pry bar or big pipe wrench and wiggle/push to see if any play,you have 5 rods in back and 5 in front,rubber bushings could be shot,redid all mine years ago,it's a labor intensive job.
"Elana has termed it knocking, and says it sounds like it is coming from below floor in front of fridge"
Are you sure your bowling ball didn't come out of its carry bag down in the basement? 😆🤣
But on a serious note, could it be something loose down in the basement?
My vote goes to a shock bolt not tight enough and it is moving in the mounting brackets. We had that and one in rear just needed to be tighter. Problem solved.
Johnh
Looks like you still have the original Bilstien shocks,consider upgrading to Koni FSD,will be a world of ride improvement.
Shocks, shock bushings and mounts, torque links and bushings
Scott
At the end of the day, all you can do until you have the time to put your coach up on jack stands and have trained hands, eyes, ears, and mind do a thorough inspection is track the rate of change. Is the noise getting better or worse? How quickly is the noise changing. If it's the same mile after mile, from everything you've described, don't worry. If the noise is getting worse, and you're out on the road find a friendly truck shop, show them how to block your suspension for safety and ask them to remove the rear wheels and do a thorough inspection for anything that might be awry. Do ask them to keep the rear level as they raise it and place it on jack stands. Or, just stop worrying and have a good time.
Thanks to everyone, great to have all the response. Same noise, no worse or better. 300 miles to the homestead, so just headed down the road. Jor had the front shocks replaced, backs are original. Would be nice if that is the issue, I have checked bolts, but haven't put any tourque to them. We have still had a great time, the weather the last few days has been sunny and in the 70's. We did lose a hub cap somewhere yesterday, I normally give them a little push before heading out, but failed in doing that. I of course will update everyone when I know more. I am pretty sure I didn't bring Ernie (my bowling ball) along for the ride.
Kim McCoy, I see we have a Hatfield on the forum, no feuding from this McCoy.
You also have the Real McCoy.
In our travels I was always the one noting and describing odd noises. Jeff is too hard of hearing to be able to accurately place the location of things. In our '02, we had two occasions of noise. Once it was a shock mount that needed to be tightened and the other was something loose on the tag axel. Both times I got a very discrete eyeball from the tech at Foretravel (but they loved me because we always brought boxes of donuts or bought pizzas for the entire shop during our stays), but then they had to admit that they had found something that cured the phantom noise.
What was the noise on the tag? My air brake cans rattle just wondering if that is what they found an how they fixed it.
Thanks, Larry
This was quite a while ago and I really cannot remember. Whenever we went over any bit of rough road surface something would bang underneath the coach. I knew it had not always sounded like that, so I asked them to look. They may have taken it out for a drive to help diagnose.
We made it home safe and sound. I have Shorty up on stands, I should get underneath today to check things out. Thanks
I have found 2 rear shocks, both being forward of rear tires, that are not right. I will post pics, the driver side shock bottom mount I can wiggle, the big washer I can turn freely. The other side, you can see busted metal piece. I will have all 4 rear shocks replaced as they are original. So,I replace them with the exact ones as Jor put on the front? What do I need to know about the ride height adjusters after new shocks put on. You all think this is enough of an issue to cause the clunking? Thanks again. Kim
That thing that is broken will need to be rewelded and new shocks won't change the ride height.
Kim, Ride height valves adjust the space between the top of the upper air spring plate to the bottom ot the bottom air spring plate to 8.5 inches. Shocks have nothing to do with this distance.
Koni 8805-1010 are good shocks to consider.
And I missed the broken mount and agree getting it welded will be needed. All the best getting it squared away. If you are stumped, see Keith Risch in north Nacogdoches.
I guess,I just need to ask shop if they can do this repair. I suppose protocol would be to get shocks from them? Kim
I suspected it to be loose shock mounts, looks like it is the issue.
Johnh
So the washer under the head of the bolt may rattle, but wont clunk. The other one is damaged and will need to be repaired. If it was double sheared it would have never failed. I'm starting to think that they should be doubled sheared to prevent failures. They should last a life time and do not. If it was me I would drive it home and keep an eye on it. Pull and tie the shock out of the way if it comes loose. Get it repaired at home at a convenient time. Since it has failed this would be the time to at least get that one shock mount double sheared by adding a additional mount on the other side of the shock for the bolt to go threw a mount plate, the shock, and the new mount plate'
Stewart and Stevens in Longview is a good shop. They fixed a exhaust manifold leak on mine and found a split charged air cooler.
Wow the increase in power was amazing.
If you are a motorcade member try getting parts from Foretravel. I saved a few thousand dollars in the charged air cooler from Foretravel.