I just got my 2000 Mitsubishi Pajero IO 4x4 (automatic transmission) back from the mechanic after a complete engine change*. And now it has a nasty vibration, but only at certain engine rpms (around 900 or 1800rpm) and only once warmed up (engine running for 15-20 minutes before the shake starts). Vibration is bad enough I pull over and sometimes the check engine light comes on.
I have been disengaging the overdrive to force the engine to rev higher. No shake at higher revs that way. Is this going to damage the engine?
I could see a bad or loose engine mount causing a vibration only at certain rpms, but why would it not shake when the engine is cold?
I feel the vibration particularly through the transfer case shift lever. But I can’t think of a reason an engine swap would unbalance a drive shaft. Maybe it is engine shaking and I’m feeling it there due to the mechanical connections to the transmission and then transfer case?
Maybe it is dumb luck and now is the time something else decided to break on my car?
So, Dopers, what else should I check. Anything this modestly mechanically inclined guy should do before just taking it back to the mechanic for a ride along?
I have checked the engine oil and transmission fluid and levels are ok.
*Check your damn oil. Even if you got back from your vacation five hours late due to a cancelled flight and change of airlines. Even if it’s almost midnight and you are only putting $5 of gas in the car to get home and are going to fill it up and check the fluids tomorrow. Yeah. Especially then. Ouch.