robi.robison@verizon.net Report post Posted November 7, 2009 My 2004 Monaco Diplomat Cummins/Allison recently began the following: When on level Interstate traveling about 60 or 70, the tranny is in 6th gear. Boost is low. We're rolling nicely. Then I apply the cruise control and the tranny downshifts to 5th gear and STAYS in 5th gear. Canceling or turning-off the cruise control ... and the tranny shifts into 6th gear. Anyone else experience such a problem? Share this post Link to post Share on other sites
wolfe10 Report post Posted November 7, 2009 My 2004 Monaco Diplomat Cummins/Allison recently began the following: When on level Interstate traveling about 60 or 70, the tranny is in 6th gear. Boost is low. We're rolling nicely. Then I apply the cruise control and the tranny downshifts to 5th gear and STAYS in 5th gear. Canceling or turning-off the cruise control ... and the tranny shifts into 6th gear. Anyone else experience such a problem? Welcome to the FMCA forum. Best answer is to call Allison on Monday: Allison help line 800 252 5283 Please verify what engine/transmission you have-- is the the Allison 3000 6 speed? And does it do this in both regular and economy modes? Brett Wolfe Share this post Link to post Share on other sites
robi.robison@verizon.net Report post Posted November 7, 2009 Cummins 350 HP ISL Engine with Allison 3000 MH 6. The control panel has the MODE button...but I've not used it or changed any setting from that of the factory. We put 20,000 on the Diplomat with the cruise control working fine. Then the 6th-to-5th shifting (when initiating the cruise control) became intermittent. It seemed that stopping and turning-off the engine (like: at a rest stop) would "reset" something, and the cruise control would work fine for a while. But here of late, the 6th-to-5th shift happens all the time when turning the CC on. Share this post Link to post Share on other sites
wolfe10 Report post Posted November 7, 2009 Give Allison a call on Monday. And if you drive between now and then, see if the symptoms are the same with mode ON and OFF (little light by mode button ON= Economy Mode). You can also use the shift pad to check for codes-- your Allison owners manual gives the easy procedure and meaning of each code. Brett Wolfe Share this post Link to post Share on other sites
djponthego Report post Posted November 27, 2009 We experienced the same problem with a 2004 HR Abassador with a Cummins 330 hp. There were no alarms displayed nor problems. It kept getting worse and finally lacked power to climb hills in 6th gear regardless of cruse on or off. It acted like a fuel problem. I changed the primary fuel filter and it was better for a bit. Finally I changed the secondary filter and everything was back. Lots of power, held in 6th up hills and better than I had remembered. Maybe a possibility for you. The problem went away with the filter change. Maybe the pressure into the injectors was low enough that the ecm made the shift due to low pressure. All I know is, the problem went away with the change of the secondary fuel filter. It only had about 12,000 miles on it. Give it a try. Darel Share this post Link to post Share on other sites
robi.robison@verizon.net Report post Posted December 5, 2009 Thanks all. I'll replace the secondary fuel filter. And Tranny-codes were checked -- no codes other than normal. Robi Share this post Link to post Share on other sites
