I had a problem with a vibration that started at about 45 but never went away. I was told to check trans damper by using a pry bar and see if you get any verticle movement. I finally had the transmission rebuilt after new tires and new u joints. Stewart Stevenson in Longview TX is familiar with this problem. The P3 bearing at the back of transmission is bad. Supposedly they can be tightened with a special tool, this did not fix mine. I used Inland Trucks in Dallas, a partial overhaul with 6 months warranty 3K range, total overhaul 2 yr warranty – 7K range (I have 3060 R and retarder adds to cost). I would not go back to Inland as I opted for total overhaul due to warranty and transmission had a small leak, and they try to charge me for repair. I would just do repair and not overhaul after my experience.
I was told this P3 bearing was a problem on 97 and 98 36 feet coaches due to such a short driveshaft. My Unit had 43,000 miles on it. Larry Bradley 98 U270
My 96 U295 developed a vibration in the rear of the coach. The problem was the transmission P3 carrier. Apparently there is some kind of “nut” in the transmission that holds the P3 bearing in place and this had come loose which in turn wore the inside of the bearing carrier. Go see an Allison dealer. He can diagnose. Cost about $2,000 to $3,000 to fix. indio192
Foretravel is very aware of this problem. If you talk nice to them, they might be able to get Allison to pick up part of the bill. Talk to Donnie Aeriola (sp?) at Foretravel. He knows about this problem.
We own a 1996 U295. In 2004, it developed a vibration in the driveline. We took the coach to the Allison facility in Spokane, Wa. Quoting the invoice: “Found failed “P-3″ carrier. Remove necessary components for access, replace failed parts, reassemble, check driveline angles, verify correct operation.”
The total bill was $2497.42 but that included changing to Transynd. Without completing dissecting out the costs, it appears the actual P-3 carrier replacement was approximately $1900.
What I recall (again from memory and being non-technical), we were told that this failure was common in this year’s coach (we have since met another FT that had the same issue). Apparently Allison assembled the transmission with the wrong torque for the nut that holds the P-3 carrier. This caused the failure. We worked this issue through Foretravel (Keith was working at the Liberty Lake facility which helped us when it came time to adjust the ride height). Foretravel, without us, even thinking to ask, got Allison to pay half the cost of the repair. This apparently was unique to the U295 (the U320 for that year had a different transmission). Gayle McNeece 1996 U295
I had the same problem took it to two different Allison shops and both tightened a nut in the P-3 carrier. This fixed the vibration for a while but it came back. Took the rig to a shop in the east and they said the bearing was shot. I was told that Allison knows about this problem and has changed their specs. I don’t remember the torc but it is double what it was in 1995. To fix this they had to remove tranny. They showed me the problems every step of the way. $2,760.00 later and 10,000 miles all is good… The vibration started around 100,000 miles. Jerry 295C-1995
The damper is oil-filled and only used on some engines and helps keep the rear bearing of the transmission working. I thought that the rear shaft bearing would have to be replaced, not the whole tranny.
Some time ago our damper was found to have vertical movement. Removing rear yoke, the rear bearing bolts in the center of the output shaft were loose. An upgraded pair of Allison bolts were installed. By catching the movement of the rear shaft, we may have saved us a bigger repair.
About 14” in diameter, about 2” thick unpainted steel round, bolted to end shaft of transmission where driveshaft is bolted to the transmission. I can’t miss it. Rotates with the drive shaft. We have the damper.
Foretravel did a no/charge to us, ‘recall’ for our drive-line many years ago. We did not have any vibration problems.
They used angle gauges on the rear axle and back of transmission to correct the angle of the engine/tranny by putting a spacer under the single front engine mount at frame cross-bar just under where belt pulleys are located. Then installed a different length driveshaft. We paid for new U-joints which were not included in ‘recall’.
Supposedly this was all needed to prevent damage to rearmost output shaft tranny bearing (P3). I understand the damper is needed for the same reason to protect the rear bearing. Maybe as Larry said because we have a short driveline.
I would
only do major transmission repairs at Allison. They know the tranny and
have multiple locations in about 10 states. Stewart Stevenson in Longview TX is
the Foretravel shop of choice as they see lots of Foretravels because they now
are the closest Allison to
Nacogdoches.
Foretravel may purchase their transmissions through the Stewart Stevenson organization, which is very large. http://www.ssss.com/
Also, Allison in Quebec checked our damper play with a pry-bar.
Bill Willett hit upon another problem of inadequate U-joint lubrication. Each of the two U-joints has two grease fittings. Each fitting can force grease into all four bearings. Fittings should be greased until some old grease comes out ALL four bearings. Many times one bearing will not expel grease because it is much ‘tighter’ than the others.
Important to request that when greasing U-joints that grease is applied until all four bearings expel grease. I think that a faster powered continuous grease gun does the best job as it keeps a lot of greases flowing. Also grease both fittings to better reach the bearings closest to the fitting.
Doing your own lubrication ensures a good job and allows greasing more often. And guarantees tech does not put chassis grease into disk brake greasing fittings, which is a very common problem. Barry & Cindy 1997 Foretravel U270 36′