Hello all, I'm new to your site and looking to purchase my first diesel pick up truck. I have had several gasoline pick ups but never a diesel. I am particulary intrested in the Chevrolet Duramax. Here is where my questions start.. Which generation engine is the best? (I'm going to buy used) How many miles can I expect out of a diesel engine? Did all Duramax diesels come with the Allison tranny?
I have done all of my own repairs on my previous trucks, but know nothing about a diesel. Are they easy to diagnose and repair? Are there reocurring problems? Is there any particular generation I should stay away from?

Thanks in advance for your help!!

Well your opening a big can of worms asking which is the best generation of the Duramax. Yes they all came with the Allison transmission (auto). The diesels are a little more expensive to fix (if any ever goes wrong with them) and really the only recurring issue is the injectors on the LB7's. However GM has extended the warranty to 200,000 Miles. My vote is for the LB7. The mileage thing all depends on what you do with it and how hard you push it.

Which generation engine is the best? (I'm going to buy used)

There are varied opionions on this but The LBZ(third gen) has never given me any problems and it was the only one to come stock with the six speed allison (all the others have five) which helps with mileage a bit.
How many miles can I expect out of a diesel engine?
With proper maintainence(sp?) you can expect the diesel to far outlast the body. Some people have had them go as many as 1000000 miles before needing any major repair some generations had problems with overheating and injectors but you can do a search here to find out which particular ones those were
Did all Duramax diesels come with the Allison tranny?
Yes unless it is a manual.
I have done all of my own repairs on my previous trucks, but know nothing about a diesel. Are they easy to diagnose and repair? Are there reocurring problems? Is there any particular generation I should stay away from?

Diesels are easy to diagnose and repair as a rule however many of the diagnostics on the duramax require a Tech II which is a computer used by GM techs. As far as recurring problems go some duramaxes have injector issues and some had a problem with overheating the third generation dmax(LBZ) does not suffer from either of these problems. As far as staying away from one or the other generation I dont think any of the issues are serious enough to go that far. Look for the best deal all of the issues that are known have some resoulution to them.

Good luck looking for your truck. Hope to see you here soon.:)

I dont think it matters which Duramax you go with, you will love any of them. My LB7 has a tad shy of 70,000 miles on it, other than 1 high pressure fuel pump going out at 6,000 miles, I have not had 1 bit of trouble with this truck. I bet at least 35,000 - 40,000 miles of mine are towing over 12,000 lbs.