Volvo 780 making huge grinding noise when make slightly right turn

What about the u joints? Unless you have to replace the whole steering shaft wich comes with new joints.

 

Everything in the front end good and greased? Socal mentioned a good point, U joints in steering shaft. A lot of people forget about the one up under the dash and it never gets greased and will cause your steering wheel to bind up and make you think something is seriously wrong.

 

Some models never get greased.......they are nonservicable u joints. The new units have zerk fittings so you can grease them

 

Ive gotten at least 3 x the wear from new non grease sealed u joint on my current Truck. Made a believer out of me. Will replace both with same when due

 

You might want to check King Pins and all steering parts. Don’t Know what else short of steering column bearings

 

A "huge grinding noise" to me just doesn't quit fit a steering issue (possibly air) that still actually operates the truck without some kind of steering wheel shake, slip or lock. I would want to separate the truck from the steering in 2 ways. Disconnect steering box arm linkage and run it full travel, If the noise is still there, you've certainly isolated it back to the steering components again. The second way would be to jack the frame to get the weight off of the king pins while operating the steering full travel (binding king pins or linkages) to see if the "grinding" noise can be duplicated, but that's just what I would do before I start removing items. I've heard unrelated items such as cab mounts make god-awful noises during a turn when the weight of the cab has shifted. Now a "new" steering box installation is almost bullet proof except for centering maybe but you can mess up a pump if your careless and in a big rush, I'll stop there for now until you isolate the problem. There is a whole lot of good professional talent running this website (way beyond me) that can make sure you get the answers you need.

 

Put thicker oil in the steering pump. Like 15/40. Check if that makes it quiet.
I can not say it will fix your problem.

 

What sucks is the shop is just throwing parts at it and not properly diagnosing the problem. Find a new competent shop and get if fixed.

 

Spring hanger bushings can make a creaking grinding type of noise when you turn the wheel.