UK Car Repair: Jaguar S 2.7D Automatic, chrysler new yorker, pan gasket

Question
When slowing down to a stand gear box goes from 2nd to 3rd with a thud. Also when running at low revs a humming type vibration from gearbox. Also, not changing gear at correct revs.

Answer
Hello Charles, I would basically advise replacing the gearbox. It is an expensive item but it is also an item with no user serviceable parts inside, it contains a myriad of valves and solenoids and any one of these can be faulty. The only maintenance the diy'er can perform on an automatic box is fluid levels and change the filter and pan gasket, which i assume you have already done. Do you mean from 3rd to 2nd when slowing down because i had a Chrysler new Yorker in the states which did that exact same bump-shifting and not changing at the right speeds, all I did to rectify it was add a new ground strap directly from the negative terminal of the battery to the transmission control computer mounting bolts. good luck and keep me posted. - Paul