klcracing Report post Posted June 13, 2014 I have an 07 Expedition 38S, with a six speed tranny, and pulling an enclosed trailer. In the past, I have downshifted to 2nd with engine brake on and it will not keep it low and slow, and will eventually shift into third. Is this normal? Is there someway to keep it slow without having to use the brakes up. Going to Silverton Co. and avoiding passes, however the pass between Durango and Silverton is unavoidable. Any help would be appreciated! Thanks Share this post Link to post Share on other sites
kingfr Report post Posted June 13, 2014 If your coach has an engine brake rather than an exhaust brake, then this is what happens. I usually turn on the engine brake going downhill and occasionally use the brakes to bring the speed down. when the speed picks up again, repeat the process. We just drove from Albuquerque to the SF Bay area, and had a lot of ups and downs. The worst part of it was the ups, because the outside temp was 105-115 degrees in AZ and CA and the coach wanted to heat up very quickly. Spent a lot of time watching the temp gauge and gearing down when necessary. Share this post Link to post Share on other sites
wolfe10 Report post Posted June 13, 2014 Actually, the Allison will perform the same, whether you have an exhaust brake or engine compression brake. If speed in a gear increases to where RPM could damage the engine, it WILL upshift. Does your trailer have brakes? Are they working? And, though you selected 2nd gear, do you know that indeed you were in second gear. Said another way, using the down arrow to select 2nd gear, does NOT mean it instantly downshift to 2nd. It will downshift to/toward second as soon as a downshift will not overspeed the engine. What engine? If exhaust brake, have you confirmed that it IS working? What percent grade was this-- with trailer brakes, an exhaust brake and 2nd gear should be good for a 6+% grade. If 10%, yes you will need to use service brakes as well. OR, if what you are carrying in the trailer is a vehicle and you have an extra driver, drive it separately when you hit these severe grades. Share this post Link to post Share on other sites
klcracing Report post Posted June 13, 2014 Yes, I started out in second and it shifted to third at the appropriate speed, and I understand the need for up shifting to protect the tranny and engine, I was just wondering if I could keep it creeping longer without the use of brakes, and the trailer does have brakes and are working. Share this post Link to post Share on other sites
