Transmission damper failure

Topic: Transmission damper failure (Read 2800 times) previous topic - next topic

Re: Transmission damper failure

Reply #50 – October 24, 2019, 09:21:48 am

And, I have to believe that running much out of correct RIDE HEIGHT would materially increase stress/wear.

Anyone have a conciliation on that?

Re: Transmission damper failure

Reply #51 – October 24, 2019, 09:44:13 am

I'm sure that the ride height primary parameter is drive shaft angle. Maybe FT had a miscalculation of engine- drive shaft angle and found a driveshaft speed variance that produced a vibe .
Once the trans locks up in the taller gears , the crank speed variance is absorbed by the driveline and tires . Any flywheel mounted , must be held firmly with enough fasteners to resist the speed variance or it will come loose and wallow out any mounting areas.
I see a rear mounted flywheel as a bandaid at best. Maybe the later buses changed the engine angle enough to get the drive shaft dynamics right .
Look under the same year buses that dont have the wheel and compare them to those that do.

Re: Transmission damper failure

Reply #52 – October 24, 2019, 11:40:42 am

Properly designed rear axle to transmission installation should allow different operational heights without incurring any undue transmission or U joint wear. Using a conventional driveshaft, three degrees is considered maximum for normal operatons. Normally, -1 degree is designed in to insure the U joints move and are lubricated. Our coaches may be raised to the top of the airbags and moved for short distances without incurring any damage.

For off road or other installations where the angles are greater, double Cardan or C.V. (constant velocity) joints are frequently Incorporated. .

Good link for understanding the relationship between transmission and rear end pinion angle: Drive Shaft Harmonics

Pierce

Re: Transmission damper failure

Reply #53 – October 24, 2019, 11:46:12 am

Remembering some folks had engine mounts adjusted by FT to correct an alignment problem. This would most likely be necessary if centerlines of trans and rear end aren't parallel=vibration. Makes me wonder....

Re: Transmission damper failure

Reply #54 – October 24, 2019, 09:33:06 pm

Crawled under the coach this morning, prybar in hand. Pried on the harmonic balancer, movement is max of 1/32". No change over 70 k miles driven, no weeps or seeps of oil. 36' coach. Total mileage now 155K, most of it towing 5K lb toy trailer. Officially off the worry list at this point. No indication in records that any repairs were ever made on driveline prior to my ownership.

Re: Transmission damper failure

Reply #55 – October 26, 2019, 08:06:13 am

Dodged the $4.5 CB bullet yesterday, Stewart and Stephens in Longview finished repairing the transmission damper vibration repair. The P3 carrier bearing had not been damaged, the bolts which I assume "hold the bearing in place" did need tightening and new seals were required, total cost $1,140. A whole lot better than it could have been.
With the air ride suspension you will not feel the vibration from the drivers seat, if your DW says there is a vibration in the bathroom doors when driving remember to check the transmission damper for more than fractional play.
So happy Keith Risch found it before it turned into a bigger issue, the pilgrimage to NAG was worth it just for that! It's what makes the forum so fantastic, The info on where to go for repairs!

Re: Transmission damper failure

Reply #56 – October 26, 2019, 08:47:08 pm

Irish! Congratulations on your self made good luck!

Re: Transmission damper failure

Reply #57 – November 08, 2019, 08:25:05 am

Update on trans repair,took to shop Monday picked up Tuesday.They found the nut holding the bearing loose,inspected race,all
ok,installed new seal and put back together.Total charge was $900.00.The shop is G and W diesel service,in Memphis,they
are a Allison repair shop AND a Cummins repair shop,the shop foreman Eugene is very familiar with the retarder transmissions as
they do many fire engines,been to alot of shops and this one is spotless.

G and W Diesel Service (Memphis TN.) 901-948-1625
Special thanks to Irish for posting the thread.

Re: Transmission damper failure

Reply #58 – November 08, 2019, 12:03:07 pm

Just a thought here, If one has this problem, could the retarder be removed and a longer drive shaft connected to the transmission? I do not know if I have this problem as I have never checked, but I do not have any leaks at the transmission, and have not felt any abnormal vibrations. I have looked at a few other 40' coaches with larger engines than mine and the drive shafts are much shorter than my 36' with the 8.3 Cummins and 3060R transmission. To me it seems that a shorter drive shaft would be more likely to be associated with a damper and bearing problem. I always thought that the retarder was just a bolt on to the transmission extra piece of equipment, but maybe there is a difference between the main transmission cases with or without a retarder. I once had a phone conversation with an Allison tech rep and he said that the retarder does cause a slight loss in mpg as compared to the same transmission without a retarder.

Re: Transmission damper failure

Reply #59 – November 08, 2019, 02:42:04 pm

I had no leaks and no vibration but the nut holding the bearing was loose,it's easy to check Jerry.The damper should have no play.

Re: Transmission damper failure

Reply #60 – November 08, 2019, 03:40:52 pm

Quote from: John44 – November 08, 2019, 02:42:04 pm

I had no leaks and no vibration but the nut holding the bearing was loose,it's easy to check Jerry.The damper should have no play.

I will check it as soon as the weather improves.

Re: Transmission damper failure

Reply #61 – November 08, 2019, 04:40:01 pm

Jerry we have the same coach as you, there was only a slight vibration of n the bedroom door. From the drivers seat with the air bag suspension you will not know that there is a vibration. Just happened the DW walked back to get something from the bedroom while we were driving.
Might be worth checking the driveshaft using a pry. bar

Re: Transmission damper failure

Reply #62 – November 08, 2019, 06:45:08 pm

UPDATE:
Was concerned about the slight play in our trans dampener on our 1997 U295 36' 3060 trans. After reading this blog, I was only slightly concerned with the play I felt (maybe 3/16th's" or less)

Talked to S&S service manager in Longview. Super nice guy, and very helpful. Explained what may be going on with it. I could have done the job myself, but it requires special tools. He steered me to RWC in Spokane Washington. They are the only Alison facility that has the tools do this work. Service centers do not. Only reprograms and oil changes.

I took it RWC, which is also an International dealer. After inspection they didn't feel it had that much play (1/16th"), but was willing to do the job.They removed the drive shaft, dampener, and yoke, to find the locking tangs and nut tight per Allison spec's. They replaced the rear seal while in there. Our trans just had the transynd oil changed/conversion for the second time 1000 miles ago, so they buttoned it up.

I hate taking stuff into shops, but this was a good experience. Whole thing with tax (Washington state has 8.5 % tax on labor). $610.00 out the door. Well worth the money for the peace of mind, as we are leaving in February on a 3500 mile trip.

With that said, unless your feeling heavy vibration, or your drive dampener is flopping around, with heavily leaking, I wouldn't be that concerned. In my opinion, a certain amount of this is normal wear. But always better to be safe then sorry.
Cheers

Re: Transmission damper failure

Reply #63 – November 08, 2019, 07:03:10 pm

Are they the only Alison shop in the area that can do the work?

Re: Transmission damper failure

Reply #64 – November 08, 2019, 07:55:19 pm

Our coach is on the safety stands for the next week or two or three. Any thoughts about the validity of the prybar test while the coach is raised to the max?
Don

Re: Transmission damper failure

Reply #65 – November 08, 2019, 08:44:44 pm

Quote from: John44 – November 08, 2019, 07:03:10 pm

Are they the only Alison shop in the area that can do the work?

I asked Western States Cat 1st. They said they could do it, but didn't have the special tool to tighten P3 bearing. S&S said there is a special tool.
From my understanding per S&S in Longview Tx. yes, RWC would be the only dealer in my area. The other 2 shops are frieghtlinner, and Cummins NW, but S&S said they are only Alison dealers, can only do oil changes and reprograms.
When FT was here, I thought there was a Alison shop.
I asked RWC in advance if they had the tools to do this.
Chris

Re: Transmission damper failure

Reply #66 – November 08, 2019, 08:51:41 pm

Quote from: Don & Tys – November 08, 2019, 07:55:19 pm

Our coach is on the safety stands for the next week or two or three. Any thoughts about the validity of the prybar test while the coach is raised to the max?
Don

Don
When I checked mine the 1st time, it was at ride height. I checked it again when the coach was raised up while I was servicing it. It seemed tighter, which would make sense because the drive line is at such a radical angle. I may have been just over thinking it.

One would think, you would still see the up and down movement .

Personally, if the seal is not leaking, I would say everything is OK, because with radical movement, it is going to mess the seal up fast. But that is just my opinion.

Chris

Re: Transmission damper failure

Reply #67 – November 08, 2019, 09:46:19 pm

Quote from: Barry & Cindy – October 23, 2019, 11:13:24 pm

Heard that damper is oil filled, not solid steel like it looks.

I believe that the three pieces of that style of damper are : outer container donut, a very, very, very viscous oil, and the inner vibration damping donut, the inertia ring.

Re: Transmission damper failure

Reply #68 – November 09, 2019, 01:48:12 am

All I can add is,the bottom of the seal is above the fluid level and mine was not leaking but loose,must have been not far from
getting looser and leaking.

Re: Transmission damper failure

Reply #69 – November 09, 2019, 11:08:43 am

Quote from: John44 – November 09, 2019, 01:48:12 am

All I can add is,the bottom of the seal is above the fluid level and mine was not leaking but loose,must have been not far from
getting looser and leaking.

Both S&S and RWC said very little oil comes out. I actually ask if the trans needed to be drained, when I was going to do it myself.

I would imagine that the retarder holds the oil back. But don't know that as fact. Just guessing.

When I pulled my retarder temp sensor last winter, very little came out.

Glad you got yours fixed

Chris

Re: Transmission damper failure

Reply #70 – March 22, 2020, 07:39:30 pm

Update:

You can read all above, so I don't know what they did, but I no longer have any harmonic vibration at any speed.
Just finished our 3400 mile trip, was awesome to drive at any speed above 62, all the way to 80 MPH, and didn't feel/ hear the annoying faint harmonic vibration.

All they did was replace the seal, and inspect. So something happened. Maybe the drive shaft got rotated 180, maybe the seal took some play, maybe the yoke is tighter now. Maybe because I greased the heck out of the joints.

Not going to cry over it, I will take it. Best $600.00 I spent on the coach.
Chris

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