CLNK from transmission when slowing DOWN


Asked by Jul 10, 2016 at 09:13 AM about the 1963 Ford Thunderbird

Question type: Maintenance & Repair

I'm aware of the usual CLUNK when you put the car IN gear if the motor speed is too high. The problem I have is that when coming to say a junction, I slow down to say 20mph and then the transmission CLUNKS as it goes OUT of gear almost as though its letting go or something. I assume that the vacuum will at that point be low, could that effect it ?and, if so, what do I look for or adjust etc, Ford 390 automatic transmission slow running speed about 560 ( I cant get it any lower)
thanks in anticipation of suggestions,
Neil Willis

4 Answers


Sounds like drive line slack as in Universal joints.. you can adjust the transmission modulator small screw in the vacuum line barb controls upshift and downshift speed based on vacuum. But this has nothing to do with the clunk in the driveline.

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Maybe a bad motor or transmission mount.

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Thanks Auto_centic and fireird338 The universal joints are both new, the modulator is new ( although I didn't understand the note about "barb controls" The CLUNK seems to be from the transmission when slowing down as though it CAN@T let go of the drive All motor mounts and transmission mounts are new just this CLINGING to the gears as if it doesn't want to let go, then CLUNK and it lets go??? Thanks guys


Check the bolts holding the flywheel to the torque converter they maybe coming loose also may want to check the transmission to engine bolts making sure they are tight.

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