Hey i have a question i got a dodge ram 1500 with a 6 in suspension lift and a 4 in body lift. I was told the biggest tires i could go was 35 on stock axles is this true.  

What year Dodge?  Knowing the year will help with tire fitment limit.

What manufacture offers a 4" body lift?  Did you add to a 3" body lift?  Or is it some type of home made body lift?

The limit of 35" tires on 1/2 ton axles is for strength reasons, and you should really use alloy axle shafts unless it is mainly a street driven for show truck.  

Thats not true at all, I have a 2000 ram 1500 with a set
of 38.5x14.5x18's  on it and I have broke it loose a few times on the highway and never had any trouble, the only time i ever broke an axle, I was pulling out a stuck pick-up and i was pulling about 16000lbs with my wintch and put it in 4 low with 38 swapwers at the time, tried to back up while pulling with the wintch too,  and snaped the end off the driver side front axle,  and thats it.  its been one hell of a truck, and O ya its my daily driver  

That tire sizing is true, but there are variables on that.  Some people break 1/2 ton axles shafts with only 33" tires while others rarely break axles with 38" tires.  For agressive driving I would stick with 35" being the safe limit on 1/2 ton axles.  If you avoid wheel hopping and other severe torque loads to the axle shafts you may do fine with larger than 35" tires on 1/2 ton axles.  

Depends on what you are going to be doing with truck... like GM said, some die with 33's some live on with 44's... I wouldn't recommend more than a 35 or 37... but do what you want and be prepared for breakage.  

You can with 38's or 39's, but with that size you will start burning up bearings, ball joints and u joints.  The really bad weak is the pinion shafts.  With that kinda of hieght and tire size I would save the money and swap out to 1 ton axles.  

I have been running 42's on my Dana 44 front for the last 4 1/2 years and haven't broken anything yet.  Like someone stated before; you have to know when to throttle and not to throttle.  If your wheels are turned or in a bind, stay out of the skinny pedal.  Just like if you are seriously bogged down in some goopy mud, don't try to throttle out, be smart and take a strap or winch!  I do routine maintenance on the front end and have replaced the outers with chromoly units, but that is it!  Be smart and a Dana 44 is a good axle!

By the way, I have roughly 10" of lift, and a slightly tuned up 360!  Not exactly a baby of a truck!