Hard downshifts

Coopers_Dad

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When I'm towing and sometimes when I'm driving unloaded a 6-5 and 5-4 downshift will happen with a significant thump. The rest of the time the trans is smooth and quiet.

I've had it at the dealer twice and all they did was check the fluid level and scan it for codes, both of which were fine and clear. The truck has about 75k on it now.

Even with an upgraded trans in my SRT it doesn't shift nearly this hard.

Ideas would be greatly appreciated.
 

sagebel

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I wouldn't call my downshifts hard but aggressive. But only in tow/haul mode. Did it in my '11 and does it in my '12 the same.
 

Duckdawg

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Maybe your feeling the engine brake if it's only doing it in tow mode, I knowing can be kind of aggressive at times


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lincolnlocker

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Ok th ask for the comment. I have nothing to compare to as I've never had this size truck before. Thanks for your time.
like said, in towhaul its normal. mine sometimes has a brain fart and does it in normal mode too but only once or twice..
Maybe your feeling the engine brake if it's only doing it in tow mode, I knowing can be kind of aggressive at times


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engine brake? when did the 6.7s get an engine brake? they have a trans brake....
 

jcain

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like said, in towhaul its normal. mine sometimes has a brain fart and does it in normal mode too but only once or twice..


engine brake? when did the 6.7s get an engine brake? they have a trans brake....

The engine brake is the turbo vanes closing and causing high backpressure.
 

Chris.v

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I've had mine downshift so hard before it chirped the tires.


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Coopers_Dad

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Well, it's been at the dealer for a week now and I got a call saying the trans is toast and I need a new one. The conversation went downhill from there. No burnt fluid, now other shifting issues, no slipping and no flare and the trans is toast. I was expecting a valve body or solenoid issue but the entire trans toast I don't believe that.

Why the hell can't anyone do honest work anymore?
 

twofazed

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I had this problem, very hard downshifts on the highway. Went to dealer multiple times, they couldn't duplicate and said they found nothing each time. Finally I refused to pick up the truck until it was looked into further so they pulled the transmission. Turns out I had a casting defect on the torque converter. New one came from Germany or something and it too had the defect, a second one came, and now all is well. 50k miles on it since without issue!
 

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