Mitsubishi 2000 space wagon GDI

2000 Mitsubishi Space WagonThis vehicle’s engine was replaced with a 2000 Mitsubishi gallant engine and now the automatic transmission keeps reviving up once it gets to gear 3 b4 engaging and revs up @ 50 km/hr too. pls what can be done?


My guess would be the transmission fluid level is low. When the engine was swapped out they may have removed the radiator which houses the transmission cooler as well. And upon reinstalling the new engine the transmission fluid level was not checked.