I mean this seriously: Where you can get a good used replacement.
There is nothing external that can be the cause, it has had a serious internal failure and either needs overhaul or replacement
Put it into reverse when moving rapidly forward.
If a car jerks forward while in the break position it is not the Automatic Break System but rather the transmission.
Make sure transmission fluid level is correct Bad transmission pump?
the forward gear clutch pack is worn out. the only solution is to get the transmission rebult.
If it has an automatic transmission, it probably needs to be replaced or rebuilt.
The forward pump is shot or the throttle has a blown gasket
4 Speed Electronically Controlled Transmission. An automatic transmission with 4 forward gears and shifting that is controlled by a computer.
Remove the pan and check for metal debris, probably failed internally.
Sounds like you have a busted linkage somewhere
Needs internal transmission repairs. Find a good shop.
If you have an automatic transmission, it probably has a forward clutch/band problem.
If this is an automatic transmission, more than likely the transmission is on it's way to the junkyard. Usually failing transmissions lose reverse first, then the higher forward gears - last will be the lowest forward gears.