I have just had a complete Autobox rebuild as water had got into the gearbox through the oil cooler (common fault) the vehicle has had a new oil cooler this is no longer a problem. Also had 2 new speed sensors 1 year ago.
It has been rebuilt by a specalist at a great expense however I experenced after a few miles harsh gear changes where it thumped through the gears. The car at times did go into limp mode where it only had 2nd and 5th gear. After turning the car off and leaving it for half hour or so it was restarted and the problems seem to correct itself but temporarily. The car went back to the garage where it was put onto the computer and several faults registered. It was then taken to the local vauxhall dealer who updated the software on the ecu. However this made no difference so the garage that carried out the rebuild then consulted ECU specialists/Auto electrician. He was told that this may be a bad earth as these vehicles suffer from this. Again this did not solve the problem. When the car is first started it drives perfectly for a very short period. These are the various fault codes reported while plugged into the computer.
PO733 - Gear 3 incorrect ratio
PO732 - Gear 2 incorrect ratio
PO758 - Shift solanoid valve 3 circuit high imput
At oil temp 298 degrees F / 147 degrees C when cold. Temp raises with throttle posistion
Select manual only 2nd & 5th on display/auto also only selects 2nd & 5th and is as though slipping clutch pulling away/ no drive due to being in wrong gear.
Heavy engagement from park to drive or nuetral to drive
Nuetral to reverse or Park to reverse are normal.
Have been told this could have nothing to do with the gearbox or mechanics but could be a totally seperate electrical issue throwing everything into safe mode
Any advice or solutions greatly apprciated.