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Where is plug to the converter on a 3800 "89 Buick Lesabre?

(1990 Buick LeSabre)
in Morgantown, IN on March 01, 2018
I was told that I may need to unplug in order to disable overdrive. Thank you
What seems to make the problem better or worse? Accelerating seems to make vibration worse once it starts at 45-50mph
How long have you had this problem? Just bought car
Tags: vibration is terrible an, buick, lesabre
Displaying 1 answer & 1 comment
Popular Answer
on March 01, 2018

You do not want to disconnect ANY wire harness at the transmission - internal damage will result!
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on March 01, 2018

The *440T4 or the 4T60 automatic overdrive transmission* will be damaged if the overdrive gear is disabled.

The older THM 180 torque converter lock-up solenoid could be disconnected without damaging the transmission..

That’s not the case for 1989.

You may not have a *transmission problem* - recommend having experienced mechanic test drive vehicle.

Torque converter *shudder* results in the same sensation as running across rumble strips on the highway ..

TEST > ‘IF’ the torque converter is causing the problem(?) While at crushing speed and the problem you’re having is present .. Lightly depressing the brake pedal will UN-LOCK the torque converter - *torque converter shudder* (IF present) WILL disappear!

Good luck with it!
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