I am getting puffs of white smoke when you change gears. Truck starts and idles fine. Just looking for a little advice.

 

white smokes not good, it could mean a few things : head gasket blown, head cracked, or the block could be cracked, w/e it is its not good.

 

I have experienced no loss of oil or coolant. The engine has no leaks. If there was some kind of busted gasket or crack would there not be a loss of some kind of fluid.

 

If it eventually goes away it could easily be condensation in your exhaust. During this type of the year, in the morning its normal to get a white exhaust vapor up until your car reaches operating temperature.

The reason I mention this is that the same thing happened to me this past fall. I did a head gasket on my daily driver '65 Falcon and noticed a lot of exhaust vapor. It was just water in the exhaust and cold air + heat.

 

why i mentioned what i did was because a friend of mine had that happen to a 360 and it turned out to be a cracked head that was slowing leaking just enough to notice the puff of white in the exhaust, good luck

 

The earlier posts refer to water, which could be steam from condensation, or from engine damage such as a cracked head or blown head gasket.
It may also be a small amount of oil smoke which only appears white. Normally, oil smoke is blue, but it could appear white.
Try this (on as private or quiet road as possible):
Get up to about 40 in second, watch your tailpipe and and goose it. Hold the gas down for about 5 -8 seconds. (Don't overdo it and blow the engine!) If you get continuous blue smoke out the tailpipe, then you have worn engine block components, such as rings, block wear, etc. This is caused by oil getting past the rings, and burning in the cylinder.
Now, still watching your tailpipe, with the engine at high RPMs, take your foot off the gas, and let the engine slow the truck down. If you get blue smoke now, then you have valve or carburettor issues. This can include bad valve stem seals, worn valve guides, bad PCV valve, or other things. This is caused differently than above. Under high deceleration, a high vacuum is produced inside the engine. If the valve stem seals are bad (and they usually are on older and/or high mileage engines) or the valve guides are worn, this high vacuum sucks oil down into the cylinder, where it is burned and produces smoke.
Your description of the puff of smoke at gear change is quite indicative of valve oil seepage. When you take your foot off the gas to change gears, you momentarily create a high vacuum in th engine, which pulls down oil. It appears as a puff because it was only momentary.
You can do this test at any speed, the important part is goosing it under load, and decelerating under load at high RPMs. So, you could force an automatic transmission to stay in first gear, goose it from idle, and let off at 20 MPH or less. You'll get the same results because the RPMS and engine loads are the same.
By the way, if you get blue smoke when you goose it, you may continue to get blue smoke when you decelerate, but it may be caused not just by bad valve stems or seals but also by the oil which blew by the rings in the test you just finished.

Hope this helps!

 

well said