Well, the wobble is back... And now I'm concerned...

luvrbus · November 07, 2015, 04:02:17 PM

It could well be the transmission ,pay no attention to the dip stick there are plugs to check the level with on the side.They will aerate if the fluid is to high or to low ? do you know when the last time the pan was removed and the inside filter was changed

Geom · November 07, 2015, 04:17:59 PM

Clifford, what do you mean they'll aerate? Will they make a sound? Or seep fluid? I'm sorry I don't quite understand. Should I add some more fluid? While adding the fluid earlier seemed to make little difference, it feels like it might have had some? It seemed that things got more.... predictable after that. But that could obviously be a coincidence too. Should I try adding more fluid?

I do not know when the pan was dropped or the inside filter was removed, or the outside filter for that matter. I had intended on having all applicable filters checked and/or replaced when we took it in.

Also the color of fluid on the stick looked clear and golden.

Bensmc9 · November 07, 2015, 07:17:18 PM

Sounds like a driveline vibration. Check the u-joints

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gumpy · November 08, 2015, 03:20:43 AM

Still feeling like driveline. I like the flange bolt idea presented above. I lost 3 of the 4 bolts on an explorer driveline once.
It would be fine until you pushed it and then the driveline would slip off center and do exactly what you said. A worn
u-joint will do that, also, as will worn spline, as indicated by others above. Something is moving off center when under load.
Ease into it and it stays on center. Check your yoke nut, too. Could also be a worn input shaft bearing in the rear end.

bigred · November 08, 2015, 03:50:34 AM

Geom:I don't even know if this applies to your bus or even if you have an Allison tranny,but I had a similar problem on my motor home.I had the fluid changed in my tranny and every thing seemed to be working great,then sometime later we pulled on to I95 AND THE TRANNY went absolutely went crazy.It would shift up ,it would shift down it would slam from one gear to another ,sometimes on down shifts ,it would slam into the lower gear so hard it was as if you had locked the brakes down.I nursed the thing along and found out that if I took it out of 6th gear it did not seem to be as bad ,then the problem disappeared for a while ,but by the time we got back home the problem was back,although it never got as bad as when it first started.Anyway,to make a long story shorter,there is a special Allison tool that you have to use when changing fluid and filters.The guy that finally fixed mine said that it looked like when i had the fluid changed,they didn't use the Allison tool and when they buttoned it back up,it pinched some gasket and that causes unequaled pressure between the ports .They replaced a twenty dollar gasket and now the thing works like new.

bevans6 · November 08, 2015, 06:18:54 AM

I would jack up the rear and check for bad rear wheel bearings.

Brian

Jeremy · November 08, 2015, 08:55:50 AM

Quote from: Geom on November 07, 2015, 04:17:59 PM
Clifford, what do you mean they'll aerate? Will they make a sound? Or seep fluid? I'm sorry I don't quite understand.

Think luvrbus means that if the fluid is too high or low it will get churned-up and full of air bubbles (aerated), which might also cause you to get a false impression of the oil level

Jeremy

gus · November 09, 2015, 02:24:00 PM

If the shaft drops off underway you will have a whole lot of excitement, free of charge!

If you do remove the shaft be sure to follow exactly the procedure in the MM. When I had the 4104 shaft replaced the mechanic first tried it his way even after I read the book to him. Didn't work, he started over while I read each step to him and it went right together.

I don't remember the details but I do remember how funny it was, to both of us.

Geom · November 10, 2015, 05:08:01 AM

I did a visual inspection of the driveline assembly, as best I could.
Near as I can tell, all of the bolts at the rear axle end are there and none appear to be loose.
The yoke assembly at the trans side also appears intact and nothing looks missing, out of place, warped, cracked, or twisted, as best as I can tell from the manual.
I can sort of hand-rotate the drive assembly about 1/2" or so, back and forth. But otherwise there's no movement.

Near as I can tell the fluid level in the trans is the same as it's always been, when I've checked it using the dipstick. If the dipstick is not an accurate way to measure, I have no other way to check it. But so far the level is the same as it's always been, so that has not changed, and I don't think it's losing fluid. The fluid on the stick does not appear... frothy. The color of the fluid tells me the trans is not getting particularly hot, or burning fluid, or other abnormal wear. It feels like it's shifting into all gears (out of first in particular) and I can feel the lock-up engaging (although I admittedly have no idea what actually happens when the lock-up "engages").
The RPMs at speed have not changed, so that tells me that if the trans was stuck at a particular (lower) gear, I would see a change to higher RPMs. There may be other things wrong with the trans that I can't diagnose here.

Of course, none of my visual inspections will be able to rule this out as a problem, until someone with more knowledge (and more tools) can properly inspect it.

I think we'll keep on keeping on and slowly make our way down to the mechanic we intended in the first place (700 miles). Near as I can tell there's nothing overtly obvious broken. We will just keep going at a speed below the point where the wobble starts to happen.
It seems like everything is fine below the trigger speed and it does not appear to be getting appreciably worse. I've gotten to the point where I can somewhat predict when it will happen, and backing off of the throttle definitely stops it.

Realizing the answer to this is likely"it depends", does that sound like an unwise thing to do? What would you do in this situation?
-Keeping in mind that I don't have the likely necessary tools or space, let alone the proper know-how to fully inspect the driveline assembly.

oltrunt · November 10, 2015, 11:25:30 AM

Make sure you have a very liberal towing policy. Just having the insurance will probably keep you from needing a tow!

RickB · November 10, 2015, 12:42:47 PM

I suggest greasing the u-joint zerks. It may be dry and hanging up. There should be zerks on the inside of the knuckles and also one that lubes the splined shaft. You'll know immediately if it's anything to do with the u-joint's as it will change the symptoms or temporarily alleviate them. If it helps I would limp it home and pull the driveshaft off and have it rebuilt and balanced.

RB