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Discussion Starter #1
Just thought I would post in case any one else with an auto tranny experiences. When I would slow down to a stop my trans would downshift very hard consistently at 30mph. Although it would not do it with the Overdrive off (OD light on). I took it in to dealer with my suggestion they flash the Powertrain control module (Transmission control module in particular). Guess what ?! the thing operates beautifully now. Not only has the hard downshift disappeared but the acceleration has improved greatly. I always thought my acceleration was on the weak side for being a fuel injected six. Looks like the PCM module just needed tweaking.
 

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Thanks for the info! I think I am going to request that this be done. Might explain a minot anomoly that I have been having.

Justin
 

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whatroc?! said:
Just thought I would post in case any one else with an auto tranny experiences. When I would slow down to a stop my trans would downshift very hard consistently at 30mph. Although it would not do it with the Overdrive off (OD light on). I took it in to dealer with my suggestion they flash the Powertrain control module (Transmission control module in particular). Guess what ?! the thing operates beautifully now. Not only has the hard downshift disappeared but the acceleration has improved greatly. I always thought my acceleration was on the weak side for being a fuel injected six. Looks like the PCM module just needed tweaking.
Yep, and your fluid was low.....the story I got.
 
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fix

if youve ever had a delayed engagement on flat land there is a new tsb to address this problem,it involves replacing the pump for the tranny,once again this does not apply to the uphill issue!
 

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Discussion Starter #5
Auto Tranny Pump to blame again

Well heck - it seems the problem with the hard downship at 30mph is back. Reflashing the Trans control module helped since June 27, but it has returned. Dealer just informed me they contacted DC hotline and they are aware of this problem. Seems the front trans pump is losing its prime resulting in the "thump" while the auto trans downshifts at 30mph. Seems reflashing the control module justs resets all the values which is a temp. fix. DC is fixing by replacing the pump and according to them takes care of the problem. Lets hope this replacement pump is an "improved" version. Of course pump is on order and should be in by end of this week. Then they have to take out trans and replace pump. We shall see says the blind man. I will post later and let you know how it turns out. :?
 

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if you remember, i had the same problem. right now it seems to have worked itself out while i was on my moab/ouray road trip. i'll wait for it to return, take it in for service and update what solution is found.
 
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