Low-speed drive train shudder

[dhschultz39]

Purchased my 06 34' Alpine a couple months ago (50K mi), and have noticed a very slight shudder at 2 - 3 mph which can be made more noticeable by load (e.g., pulling trailer uphill). Perfectly smooth at all other speeds in any gear, without regard to load. Have lubed U-joints and slip joint - no evidence of failure without dropping drive shaft.
Took coach to Cummins NW - tech didn't notice condition while driving until I demonstrated condition to him. Provided negative diagnosis without easter egging. Considering mounting GoPro camera to observe shaft at both ends, but suspect won't show on video since camera stabilizes vibration out?
Hope somebody has had experience in past...
OBTW - about 12 - 15 pumps of grease for U-joints before lifting seal;
30 pumps on slip joint.
Thanks in advance for any suggestions.

[BrianGlenn]

I have previous experience on F350 pulling 14,000lb 5th wheel.

Driveline shudder on start out low speed due to drive line angle (drive shaft to pinion gear) changing. Starting torque on axle (opposite force from tires) twisted axle driving pinion gear/driveshaft angle upwards. Result was shudder from pinion gear. Two piece driveshafts help (driveshaft plunge) but angle force was just too much.

I added air bags to raise rear of F350 when loaded, and added a set of traction bars. Driveline angle stayed fairly close loaded or unloaded, and traction bars eliminated axle wrap.

My solution may not help with your scenario. Just sharing similar symptoms.

Brian

[twinboat]

One thing to offer is, did you notice any rust colored grease coming out of any of the U joint caps. That would be a sign of failure.


Second, did anyone check the wheel lugs for movement.

[Dave Fernandez]

Hello and Welcome to the IRV2 and the Alpine Coach Forum.

That is a lot of grease into the U-Joints, I bet they had not been lubed in a long time. I think the problem is the U-Joints, although I would also check the where the Rear Axle and Suspension is bolted to the Frame to make sure it did not move.

Let us know what you find.

[Old Scout]

As I recall, there were a number of 06 and 07 owners that experienced U-joint failure due to a manufacturing flaw in the joints used by WRV. However, these failures tended to occur fairly early, within only a few 1000 miles. Atleast one Alpine owner experienced a pinion bearing failure in the differential. Since the bearing failure was pretty much a "one-off" event, I'd be incline to think you might have joint issues...

[dhschultz39]

No evidence of discoloration or metal particles when grease first issued from U-joint seals, just my hesitation about dropping the drive-shaft and changing out U-joints.
Agreed that number of gun strokes equals a "lot of grease", but without some corroborating evidence, prefer not to easter egg (change out parts) without cause. As to axle roll, the angular displacement between transmission and differential is zero or nearly so, a troublesome situation in that for U-joints to function correctly (i.e., have the needle bearings roll ever so slightly to prevent taking a set), there should be some angular displacement. Researching now the proper suspension heights maintained by the air bags to ensure correct angle among engine/transmission, drive-line, and differential.

[dhschultz39]

Originally Posted by Old Scout

As I recall, there were a number of 06 and 07 owners that experienced U-joint failure due to a manufacturing flaw in the joints used by WRV. However, these failures tended to occur fairly early, within only a few 1000 miles. Atleast one Alpine owner experienced a pinion bearing failure in the differential. Since the bearing failure was pretty much a "one-off" event, I'd be incline to think you might have joint issues...

Sounds like a concensus to open and inspect the U-joints, the only way to see their condition absent evidence at the grease seals.

[Dave Fernandez]

Another Alpine Owner had a shudder when first accelerating and it turned out to be a bad U-Joint which also damaged the flange at the parking brake/transmission end.

I would remove the drive shaft and inspect the U-Joints.

If it were me I would just replace them if I had it apart for inspection. It is an easy replacement and cheap insurance. You are already paying for R&R so it is just the addional cost of the U-Joints.

[CJ7365]

Originally Posted by Dave Fernandez

Another Alpine Owner had a shudder when first accelerating and it turned out to be a bad U-Joint which also damaged the flange at the parking/transmission end.

I would remove the drive shaft and inspect the U-Joints.

If it were me I would just replace them if I had it apart for inspection. It is an easy replacement and cheap insurance. You are already paying for R&R so it is just the addional cost of the U-Joints.

Agree with Dave, just replace the u joints they have 50,000 miles, and you will eliminate that. Don't forget the center bearing.

When taking driveshaft out mark the ends to make sure to reinstall it the same way it came out, also remember to chalk your wheels.

[dhschultz39]

For CJ -
Little confused by "center bearing"???
With diesel pusher and ~18" long drive shaft, I only have a U-joint, shaft, slip joint, shaft, and U-joint making up the assembly. The steel strap protecting against throwing a drive-shaft has no bearing like long shafts. Presumably the slip joint has a seal of sorts at the male-into-the-female union, but it's shiny smooth with no chatter marks.
Going with reco to replace U-joints, then from there if required.
Will advise results
R/S

[Old Scout]

Allison tranny is a possibility here but they are pretty bullet-proof to begin with and you would think the issue would show up other places like at shift-points or at accel/decel. Would be curious as to tranny fuild levels, last fluid change/last filter change--I try to go for the obvious first.

[DrDaveMA]

CJ does not have an Alpine, he has a Winnebago Brave, maybe they have a "center bearing".

Dhschultz, you need to determine the perspective of the poster, Alpines are unique and owners of Some Other Brand (SOB) can think they are giving good advice, but the uniqueness of our Alpine can lead to issues. Dave Fernandez has been an Alpine owner for a long time.


Sent from my iPad using iRV2 - RV Forum
Dave, Bobbi and Fenway

[dhschultz39]

Originally Posted by Old Scout

Allison tranny is a possibility here but they are pretty bullet-proof to begin with and you would think the issue would show up other places like at shift-points or at accel/decel. Would be curious as to tranny fuild levels, last fluid change/last filter change--I try to go for the obvious first.

Tranny was "serviced" by previous owner in Aug 14; now, level normal, color and smell normal, shift is sharp with no evidence of slippage. "Shudder" only occurs in 1st gear at 3-4 mph. I am able to almost "coast" thru the speed of occurrence without the shudder occurring by poking the accelerator, then letting off, then apply accelerator at 5 mph.

Update - drive-shaft removed, no evidence of U-joint degradation by feel.
New U-joints install tomorrow, Friday; with open and inspect old joints, maybe an answer.
New observation with shaft out - can move the pinion end yoke thru arc of 0.125" on splines of pinion shaft, before being able to move yoke thru additional arc of 0.125" to take up lash of pinion to ring gear. Releasing twist on yoke removes pinion/ring gear lash. Reversing twist gives 0.125" of arc motion of yoke on splines of pinion, then additional 0.125" of lash (opposite direction from above) available between pinion gear and ring gear. Be talking to Meritor techs first thing in AM about 1) permissable lash among yoke splines and pinion splines (used to zero in my Dodge Cummins truck), 2) expected lash among pinion gear and ring gear, and 3) relative hardness of yoke vs pinion splines to determine if yoke only replacement recommended / possible, or both yoke and pinion shaft required. Any thoughts greatly appreciated.

[JLMunsil]

I have the same issue on my Alpine. It's been like this since I purchased the coach new. Like yours it shudders when going 3 to 5 miles per hour. I checked and adjusted the ride height and checked pinion angle It's about 2 1/2 degrees. I have replaced the universal joints, changed fluid in rear differential, and changed fluid and filters in transmission. I had Henderson line up drive it and had a ride along with with an Allison tech. Henderson thought I was to sensitive. The Allison tech said it wasn't the transmission.
I have just been putting up with it the last couple of years.
If you discover anything I would be curious to know what it is.