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Auto Trans Down Shift?
Allison can program your transmission to auto down shift when the Jake is on. The most aggressive is to 2nd gear. Does anyone has their transmission setup this way? What do you think?
Thanks,
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5 Replies
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If programmed most are at 4th gear select….I dont recall anyone having 2nd
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I do and have always used the 2nd gear preselect. It works the best for me.
As always, your mileage may vary.
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Our last coach was set up with a second gear pre-select. We drove it for about 125,000 miles and really liked the setup. When we got this coach, I had it reprogrammed to 2nd pre-select, and prefer that set-up. Don’t forget our transmissions are intelligent, and adapts to the way you drive.
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Our previous 45 footer was a SOB with 600hp, preselect at 2nd gear. When the Jake brake kicked in it was like standing on the service brakes. I never ran with the Jake on and turned it on when needed, shifting back between the two activation settings (3 cylinder braking or 6 cylinder braking).
Our current XLII had the preselect set to 5th gear. I first thought the Jake was not functioning… then learned to manually down shift – all the time!
When my “new driver” began learning, I had the preselect set to 4th gear. Now I can leave the Jake on 80% of the time and even out West in the long downhill grades, manual downshifts to 3rd or 2nd are rarely needed.
Like all have said, the setting is very personal, related to how you drive and your experience. I don’t think there is a wrong way as long as it works for you.
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Good information everyone, thank you.
Ok, “now for the rest of the story”. I came down Rabbit Ear Pass in Colorado into Steamboat Springs in 3rd gear full Jake on, I could not get the perfect spot ( no brakes, no throttle). So, I was braking every 30 seconds or so to bring down my rpms. At the bottom of the mountain I had hot brakes. The Jake did not seem to be doing it’s job. In hindsight I should have dropped to second gear.
We got to Coburg, Oregon and when to Northwest Freightliner, a Detroit Diesel and Allison shop. An “engine guy, a transmission guy” and a computer took the coach for a drive. Transmission was fine, but the Jake was not working to its fullest according to the DEC. Their schedule and my schedule did not lineup to have them get into the engine.
The transmission guy asked if it was set to down shift automatically, I said I did not think so because I was manually downshifting. He offered to reprogram it to auto downshift and asked how aggressive I wanted it. Not having a point of reference, I had him set it to 2nd gear. I did this most aggressive setting because I still had the Rockies between me and home in Missouri. It is an interesting program setting. Today, coming down Vail Pass on I-70 into Frisco, Colorado everything worked great. Third gear full Jake, I only braked once or twice. Nice, smooth, safe descent. I will be having American Fleet fix the Jake. They are in my home town of Springfield, Missouri. I will make a decision about were to have my transmission programmed to after the Jake is fixed.
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