Thanks to everyone who has responded to my question so far . . . . good and useful information. It seems that the manual trans. models will get slightly better gas milage than the autos, even though the milage figures posted by Toyota say the opposite. Here is a second, but related question: both the manual and the auto have 373 rear end gear ratios, but the transmission gear ratios are quite different. First gear in the auto is 3.520 and first gear in the manual is 4.171. If my thinking is correct (and it might not be), the manual transmission trucks should be better at "crawling" in first gear low range. Also, because of the lower first gear, the manual should have better engine braking capability when descending a steep grade in off road situations. Am I on the right track here?
Les - Good to see you back on the forum. I remember several years ago when a dog ran out in front of you and wife on your KLR. Very scary crash. Glad that you are recovered. - Richard
In general, the torque converter of an automatic transmission will lower the overall gear ratio of the transmission, especially the first gear. lower than an equivalent manual transmission. This is why auto's have higher gear ratios. When you think of a torque converter, think 'torque mulitpler." Because of this, the torque converter makes them very good for crawling when you are going up hill. It is also the reason that modern autos have "torque converter lockup clutches" to directly drive the input shaft of the transmission without going through the torque converter.
The draw back is that an auto (and its torque converter) isn't very good at retarding your speed when going down hill.
So, for extreme crawling the automatic may be better, but for engine braking, the manual is better. Does that help?
If I had to choose, I would go for a manual. Fortunately, I don't have to choose as I have an Allison transmission.