I do have experience in this but this is just my opinion. I would stay away from this truck and hold out for a 01 or 02 with a NV5600 six speed manual and put a good clutch in it. That combination will by far be the best way to go trans and motor wise. The 99 dodge cummins specifically also had problems with the blocks cracking.....I believe they have become to be known as the "E blocks". Stay away from a 99 cummins in my opinion. Between the reputation of the trans, block, and early VP44 you could end up buying the truck again in repairs!!!!!!!
If you are stone stuck on getting a cummins....which is alright with me, they are well engineered motors.....maybe the best overall motor ever put in a production pickup truck. I would, in my own opinion, advise you to be picky with which one you buy.
This is just my opinion but..... here is a list of the dodge cummins that I would recommend buying....after careful shopping around you will find these models to be more expensive....but that is because they are worth it. I would recommend buying the....
94-97 with NV4500 five speed standard
....weak points...fifth gear coming apart, low stock power output, fuel shutoff solenoid, restrictive stock air box and exhaust, front end parts are weak, extended cab has only two doors.
....strong points....MOTOR WILL RUN FOREVER, strong resale value, P7100 injection pump
02 with NV5600 six speed standard
....weak points...low pressure fuel pump, front end parts are weak.
....strong points...usable stock power, have seen many of these trucks with 500,000 plus miles, extended cab has four doors, four wheel disk brakes, foldable heated tow mirrors, good fuel mileage, very nice tow vehicle for heavy loads.
05-06 with G56 six speed standard
....weak points...high initial cost, hard to find
....strong points...usable stock power levels, have heard of many of these with 400,000 plus miles, stronger front end parts than 94-02 models.
Now for some Dodge models (based on reliability, power and, relsale) I would have no further interest in buying, ever....
99 with the E block
98-02 24 valve with four speed automatic
03 with 5 speed standard
89-91 all models
91-93 with automatic
07-10 with 6.7L all models (I am still not sure about this one but, so far I am not impressed.)
Remember that this is just my opinion but, I believe right now at this moment in time the best bang for your buck in the used diesel truck market is the 99-00 Ford F-250,350.
I hope this helps.