quote:

Originally posted by olroy:
If it continues to shudder in first regardless of speed, it points to a transmission problem. If it stops as speed increases, even in first gear, it broadens the problem to engine or driveline.

Another possibility is that the trans slips, causing a shudder until the clutches are fully engaged. Low pump pressure can cause this. I don't know if that Allison has a modulator valve, but it might be something to check. Many automatics increase line pressure when they sense more throttle pressure.

Back in August, I mentioned the possibility of low trans fluid. Has it been checked? A can of Trans Medic could do some good, too. Frees up sticky valves. (Shields up. Mouse milk haters, fire away!)

Have you checked the driveshaft timing?

The driveshaft for the drivetrain needs to be kept in alignment. If your shafts have been removed maybe they put it together out of sinc. Check to see if each u-joint yoke is on the same plain on the same shaft. What that means is each yoke on any one given shaft should be at the same positions on both ends.

If one yoke is put in of sinc or out of time you could get a vibration. Check that first as it requires no tools to just look.

The next item would be the u-joints that were removed. There is a good chance that a needle fell out or is wedged in the end cap. If you know which u-joints were removed pull them down and check to see if all of the needles are in place.

Grease the u-joints and check for play. Look to see that all of the caps have grease purging out of the ends. Replace any that feel hotter then the others after a short drive.

NOTE: steering shafts with 2 u-joints are 90 degrees off. Do not put in a straight line like a driveshaft or severe binding will follow!!!

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http://www.truckroadservice.com/

Bill:

Thank you for your informative response. I learned at bit today and hence today is a good day.

Thanks:

Timothy

Whoopee!! The problem has been solved. I took the motorhome to a Detroit Diesel/Allison Transmission shop in Springfield, MO and they told me that the U-Joints were out of sync by 90 degrees. The last tiime I had it towed (driveshaft was removed for towing) it was put together wrong. A simple way to look at it; if you were to lay it on the floor, it should lay flat. No more shimmy/shake. Best of all, because they didn't get me in until a couple of hours after I got there (I had an 8:00 am appointment) they didn't charge me. I would have gladly paid just to get it resolved. This was a good day.

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I said that it would cost you no money to look. It looks like it cost you no money not to look.

I'm glad they found the problem for you. Now,
1) call up the place that towed you or reinstalled your driveshaft and complain. If that shop has any quality control the boss would want to know.
2) Let us know who did or didn't do you right. We don't want to have anyone working on our coach that can't reinstall a driveshaft the right way. That being said everyone makes mistakes. The good shops are the ones that will admit and reimburse!
3) When asking question the simplest answer is usually the right one. Most people think that there are big problems and go into panic mode. I know, I listen to them all night long & have told many of people (over the phone) what to do to fix it. "Oh it's not that" is what I hear and after going out on the road call and fixing what I told them it was for a lot of money they get upset. Don't get upset with me for fixing your truck after I told you what it was! I get paid to get out of bed at 3am on a Sunday and I charge accordingly!
4) Consider this a lesson and take the info you get on this site. There is a treasure trove of free advice from some very knowledgeable people. I am glad I found this place and consider you my friends. So if you want to know something I will always help a friend, and like a friend, let him/her know when they stepped in it.

If any of my friends breakdown around here call me. I will always help out a friend. Anyone of you can call me for advice if you don't understand what it is that I said/typed. Just click on the link below and pick up the phone.

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http://www.truckroadservice.com/

[This message has been edited by Bill (edited October 24, 2005).]

quote:

Originally posted by bill h:
The typical drive shaft can only have a certain number of positions. Sometimes just trial and error will eliminate vibration.
You might even get lucky and find some marks on the yoke flanges that would indicate factory matching.

It might be a good idea to go out and put some marks on the flanges so the next time the driveshaft is disconnected the guy has something to follow.

"It might be a good idea to go out and put some marks on the flanges so the next time the driveshaft is disconnected the guy has something to follow."
I am on my 4th Toad using Remco driveshaft disconnects; on each I spray-painted the u-joint/dshaft connection before the Remco was installed. When the Toad is changed, the original driveshaft is reinstalled and, with the paint markings, everything lines up correctly.
PS: I install the original toad u-joints on the Remco shafts and have never had a problem, regardless of how it lined up.

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"You are what you drive" - Clint Eastwood

Forget exact year, about the same time as the Chevy lumium thro away block, Triumph issued a tech bulletin to solve drive train vibration problem on TR6, the wedge "Shape of things to come."
Remove drive shaft, reverse and re-install.