My Truck overheated and lost coolant. I had to add about 2 1/2 L of coolant. I see no leaks as I left it run for 20 minutes and it has held the coolant level now. If I put it in drive or park or reverse it's smokes like hell. ( This happened before) If I put it in first second or third gear and it drives fine and it does not smoke. I've noticed I've used a bit of transmission fluid. As I've said let the car run for 20 minutes and it is not over heating. What the heck is gong on here. Drives fine.

 

Idle is not the same as putting a load on it. What color is the smoke, white? If so you probably have a bad head gasket. Check your oil level and color.

 

Oil pretty black and yes white smoke. Loosing red transmission fluid too but think just hose from reservoir. How expensive is a head gasket job? Thanks

 

Generally speaking if you do the work the largest expense is having the heads machined flat. If a garage does all the work the labor will be largest expense. DIY maybe $500 tops. If I called the machine shop in advance to have the heads milled on a Friday and back in my possession same day I could have it running by Sunday afternoon. YMMV.