2001 Grand caravan 39k has a bump when downshifting at about 35 mph. At times this bump is loud and will wake you up if you are trying to drive and sleep, this bump only occurs when the Od in engaged, and does not occur when I select the #3 position. The fluid is red the level is good. Any ideas, thanks.

 

You will probably have to go to the dealer. There is a TSB for that concern, involves replacing the transmission front pump and reprogramming the trans module due to a machining defect in the pump that allows the torque converter to drainback overnight. When the vehicle is restarted, the TCM detects a loss of prime because the pressure switches haven't closed when expected due to the refilling of the torque converter and is steps up the underdrive clutch value and you get the bump when it downshifts.

 

Do you happen to know the TSB number so I can help the dealer, just incase they may need the help... I called DC hdq and they could not find it based on the info you provided me. Thanks

 

Sorry, I thought it went farther back than that, it only goes back to vehicles produced after 6-02. Was it run low on fluid by any chance?? TSB number 21-004-05.

 

No not to my knowledge.

 

If you are going to take it to the dealer, have them reference the TSB and tell them that those are your symptoms. Maybe the pump is worn out in yours.

 

Will be visiting the Dealer on Wed, unless there is some way I can fix it. Thanks

 

It seems that their answer was to flash the tcm based on some TSB dealing with hard shifting. So far it seems to have worked, the downshift clunk has vanished.