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Reprogram transmission during engine braking

Yahoo Message Number: 79422
I have an 08 magna with a Cummins 600 ISX engine. When traveling at 50-60 mph and engaging the engine brake, the Allison transmission shifts to the 3rd range which over revs the engine when it goes into third. My 05 Magna only went into 4th range which worked much better. I am considering having the trans reprogramed to shift only into the 4th range under grade braking. Has anyone done this? Thanks,

John

08 Magna 6887

Re: Reprogram transmission during engine braking

Reply #1 –
Yahoo Message Number: 79443
I have the same coach 6948 the indicator says third but will not shift into 3rd untilll a low enogh RPM is reached. Leave it alone and enjoy.
My 06 Alure acted the same way as you 05.

Re: Reprogram transmission during engine braking

Reply #2 –
Yahoo Message Number: 79446
My trans. does go all the way to 3rd and the engine rpm is as high as 2500. The max is supposed to be 2100. I know the manual states that the engine rpm will not allow the trans to shift down until the rpm is lower, but it does.



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From: dwells1932

To: Country-Coach-Owners@yahoogroups.com Sent: Tuesday, May 22, 2012 10:58 AM Subject: [Country-Coach-Owners] Re: Reprogram transmission during engine braking

I have the same coach 6948 the indicator says third but will not shift into 3rd untilll a low enogh RPM is reached. Leave it alone and enjoy.
My 06 Alure acted the same way as you 05.

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Re: Reprogram transmission during engine braking

Reply #3 –
Yahoo Message Number: 79450
The tranny can't over rev your engine. The limit with fuel applied may be 2100 RPM, but when in the braking mode with no fuel applied the rev limit is around 2500, when the limit is reached the ECM of the engine will tell the transmission to up shift. On some coaches when using the engine brake the transmission seeks 4 th gear, some of the other heavier coaches seek 3rd gear. Because I travel the Colorado high passes I had Gary from Allison in Coburg program my transmission to seek 2nd gear automatically. This time when I had the engine oil changed Chris went with Valvoline and my over the road oil pressure increased from 38 lbs to 47 lbs, with an ambient temp of 105 degrees descending into Palm Desert from the east on I-10. I could hold 60 mph 90% of the way with 3 cylinder and the remainder with 6 cylinder braking with a combined weight of 43,000 lbs. Where before I was in the 6 cylinder position and had to use service brakes for final control with Shell Rotella.
TWI 2004 Intrigue 11731

Re: Reprogram transmission during engine braking

Reply #4 –
Yahoo Message Number: 79451
PS remember to turn off the cruise control when going down grade and the economy control, too. TWI 2004 intrigue 11731

Re: Reprogram transmission during engine braking

Reply #5 –
Yahoo Message Number: 79452
Thomas,

I've heard exactly what you wrote before. Last year while in the Cat repair shop they told me if the ecm records an over rev then they void the engine warranty if it fails. I don't know the truth I'm just relaying what they said but then I'm not their biggest fan either.
Kevin Burns

2000 Affinity #5865