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Used Seafoam to clean Intake --- Now transmission upshifts VERY slow with loud whine

17716 Views 10 Replies 7 Participants Last post by  DaveInColumbus
I disconnected a vacuum line from my 2003 T&C, reved 3.8 Engine to 2k RPM and let the intake suck in Seafoam to clean the Engine. Engine started to misfire and hesitate at idle and Tranny immediately upshifted VERY slow with a loud whining noise. I changed plugs and wires and the engine misfire code / rough idle went away and never came back. I then changed solenoid pack with a borg-warner replacement from Ebay ($100.00 and 100% feedback rating from vendor) This did not fix the slow upshift problem. Also, sometimes I have to lift my foot off the throttle in order to shift from 1st to 2nd and 2nd to 3rd. I personnaly changed the tranny fluid at 65k and 75 k with mopar filters and ATF - 4 fluid. The van currently has 85k miles. The level of fluid is perfect with never a leak. Yesterday, I disconnected battery overnight with no success. The engine and transmission have always run good to great until I used the Seafoam! ANY IDEAS??

By the way THANK YOU to all the posts about changing plugs, wires, solenoid packs and tranny fluid / filters. They are fantastic / accurate posts that saved me $$$$$$$$.
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Sounds like the transmission got reprogrammed somehow. A "quick learn" might fix it or wait for upwards of 70 restarts, by which time it should relearn itself and be smoother. Does the problem just happen during warm up or all the time?

Another item affecting shifts is temperature sensors and your transmission may be getting a "cold" reading. Here's how your transmission works with regard to temperature.

Did you disturb any electrical connections during work you did? Is your engine coolant temperature normal? Speedometer working okay? Do a key dance and see if there are any codes showing up?
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