shut off driving or tranny downshifted at high speed

dieselguy · **Posted:** Tue May 13, 2014 6:14 pm

ok guys, im usually more on top of my game but I was coming back from dentist "had a root canal" and I had sort of nodded of for a split second when all the sudden I hear this loud noise, sort of a bang as if someone just hit me in the rear, I look up and the tranny has down shifted and at 75mph that ran my rpm's to about 3,500rpm. now at first i thought the transmission was acting up and inadvertently down shifted, as i continued down the road the engine felt a little sluggish. im thinking now that maybe the engine died and in doing so the transmission down shifted causing it to engage engine and restart. if i hadn't been sleeping i would have been paying attention but that's the way it happened. and yes i thought about the guardian angel theory but i think he would have just nudged me on the shoulder, lol.

Mike92104 · **Posted:** Tue May 13, 2014 6:46 pm

Mine has downshifted like that on cruise control on a downhill grade. It can definitely be a bit of a surprise.

dieselguy · **Posted:** Tue May 13, 2014 7:07 pm

hum, that's another issue i haven't addressed yet. after i put this thing together my cruise doesn't work, the light comes on but it doesn't engage.

ATXKJ · **Posted:** Tue May 13, 2014 8:56 pm

if you have a scangauge or similar plugged in - that happens - overloads the data bus and it'll kick out of overdrive on the highway.

dieselguy · **Posted:** Tue May 13, 2014 10:53 pm

i have a bully dog monitor plugged in, but it has been acting crazy, not displaying all my parameters.

flash7210 · **Posted:** Wed May 14, 2014 1:16 am

dieselguy wrote:

i have a bully dog monitor plugged in, but it has been acting crazy, not displaying all my parameters.

Bingo!
Unplug it and everything will be back to normal.

dieselguy · **Posted:** Wed May 14, 2014 11:31 am

so what yall are telling me is the computer doesn't have enough grunt to run everything. its a shame such potential this thing has but to save a few bucks here and there the mickey mouse stuff they assembled it with. boy do I miss the day of made in America with pride. built to last forever standard our grandparents stood by. you guys know the old motto,,what goes around comes around, and boy do some big corporations have a payday coming.

geordi · **Posted:** Thu May 15, 2014 11:39 am

It isn't a matter of the computer system having enough power or not. It is simple programming of controllers that wouldn't normally be speaking the same language or protocols. One possible explanation: The engine computer speaks Bosch, the body computer speaks the new Canbus protocol, the TCM is on the old Canbus system, the ABS is on some other protocol... And then you have the question of who will be the leader in this electronic kindergarten class.

Each of the computers wants to be a controller of the data bus, and it is a tenuous system that Chrysler bodged together. When you add in ANOTHER participant in the conversation, there is just too much traffic and eventually the weakest player (the TCM) throws it's hands up and says "I can't take it anymore!" and reboots. When this happens, the transmission drops into default mode briefly, which locks out OD (4th and 5th) because the button circuit hasn't detected / rebooted yet. This is why you VIOLENTLY shift to 3rd at speed.

Obviously you don't want this to happen, and the extra controller (any external scanner or device) is what causes it. I have only seen ONE CRD with a scanner device that didn't seem to cause this problem, it was a scanner-wifi-hotspot creator that works with the ipad and iPhone. I don't recall the exact name of it right now, but I will try to figure that out and get back to the thread with it. But your Bully Dog scanner was the cause of your problem.

Sent from my iPad using Tapatalk HD

dieselguy · **Posted:** Thu May 15, 2014 5:15 pm

thanks so much for that info, it makes sense. please get back with me on the Bluetooth scanner cause im looking at those and I have an android phone and a windows phone I could use with it.

shut off driving or tranny downshifted at high speed

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