i'll be the first i don't know much about the dmax because all i got is the 6.5 and those are great, but anyways onto the topic

friend owns a lly and has taken the truck to the dealer several times because of "cracked injectors" now is this a problem on the trucks? or what could be causing the problem?

second question, apparently when towing up hit with a load of lumber ( no exact figures given to me) the allison transmission did not shift down, instead from what he was telling me that it started to bog and didn't shift till 1000 rpm to the lower gear. what could it be?

does anyone have a clue here?

Have not heard of either of those problems, and have had nothing like that happen in my truck. It might be helpful to get a bit more info from your friend.

yes, more information is needed. Cracked injectors, sounds as if the technician screwed up putting them in. I have yet to hear of cracked injectors. how many miles on the truck? when was the last fuel filter change? are there any codes or the SES light lit? are there any mods on the truck? what size tires are on the truck? when was the last time the tranny was serviced?
a friend of mine had a similar issue with his LB7 and once I changed his filter, it cleared up. He had just purchased the truck with 40K miles on it and when I changed the filter, due to it's sluggishness, it appeared to have the original filter on it. The filter was full of rust and vfery nasty. changed it again after 5k miles, and showed clear. Which confirms my theory on the filter not being changed for quite some time.

Please gather more information from your friend and get back to us. Everyone in the forumn can supply some sort of help in this.