Drive line help

1994 kenworth day cab converted to dump truck. I having a issue with braking u joints over and over. Between the center bearing front drive. What I have done to the truck to fix this is. New drive shaft and center bearing. New bump stops and air bag valve. New transmission and clutch (was time for it). It never did this till 4mo. ago and it’s costing me a arm and leg and I don’t know what more I can do. Some one got some advice???

 

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.

 

This truck we been running for 5 years with no issues. Truck has full air bag suspension 4 bags per axle with a drop axle. Drive shafts are properly phased and all caps and strips was tight. Transmission is a fuller 10 speed and the front rear is a Eaton DS402 don't know gearing off hand. Motor is a cat C15. Every time drive shaft brakes its on take on in soft dirt. 2 days ago i broke both u joints and the yoke on the front rear and the slip yoke. And the bed is a dove tail 15'. sorry im all over the place. tomorrow i have a yoke to come in so i will have it at the shop and i will measure the ride height. does some one know that off hand?

 

"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.