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Discussion Starter · #1 ·
My 2003 Duramax w/Allison for 50K miles ran at 1800 RPM's at 60 MPH. Now I am experiencing times when it will run at 2000 RPM'S at 60 MPH. If stop turn off egnition and restart it will again run at 1800 at 60. Get usual response from Chev Dealer, leave it and we will look at it.:cool2: Anyone have any ideas on what is happening??:muahaha:
 

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Do the RPM's eventually drop down to 1800 RPM? When it is cold it can take quite a while for the torque converter to lock up. If it never does lock up after 10 miles or so I would guess there is something wrong with the torque converter or the controlling system for lack of a better term. Are there any codes?
 

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Discussion Starter · #3 ·
intermittent RPM'S

When I notice the RPM'S at 2000 at 60 it is usually very steady. The Truck will have been driven over 20 miles. Sometimes this happends each morning after starting and heading off. But, it also does this at times after vehicle has been driven over 30 miles, shut off, and restarted within an hour. Usually, if I stop the vehicle and restart it will make the final shift and be at 1800 at 60. It is getting do this more often. The Chev garage said it was no use looking for codes because the check engine light has not come on. Any guesses? I would think it is some sensor that is not letting the TCM no the car has warmed up.
 

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I'm Not a tech BUT, there's a lot of hub bub about speedometers starting to fail around here, mine included !
 
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