Drive line help

Are the rear suspension springs rated for the weight that's carried in the dump bed?

Sounds like the suspension is getting overloaded or the drive line angle is not right.

 

What he said and are you driving on the hard road with the P/D locked in? What engine are you running and what are your u-joint numbers? Is your driveshaft properly phased?

 

First, check that the ride height and axle angles are correct. Second, consider your current gearing to the application since the chassis went tractor to construction. Do you find yourself slipping the clutch in situations to get moving, if so a lower gear may be needed. Third, be happy the u-joints are failing and not the trans or the diff. Which is more to repair? Farmers buy road tractors all the time and forever break driveshafts until a gear change is made.

 

"Every time it breaks is on take off in soft dirt"
Answered your own question- geared wrong for off road work,

 

Spicer u-joints or off breed ones? Trans the same as old one? New clutch grabs where the old one used to slip when taking off? Ill second the ride height check. New driver?

 

What is the loaded Weight "GROSS" of the truck?

 

If you did not change the wheel base, and did not change the drive line angles, then your drive shaft is underrated for your application, or simply operator error.