Steering problems. What the Berkeley.

This issue started suddenly, didn't it?

Making me suspect a frozen ball joint (IIRC, you replace the tie rod ends since the issue started) or back to the steering box itself or mounting issues, like a cracked frame around the box.

Also, is the alignment being done with air in the rear bags?

imagine the truck is perfectly level with no air in the bags, and you dial in 4 degrees positive caster.   then you add air to the bags and raise the rear 1".   i'm guessing wheelbase is about 120".   then the rake angle is arctan(1/120), or about 0.5 degrees.    so you've just lost 0.5 degrees of positive caster.

unrelated to the bag issue, but i remember reading a long time ago that one of the big 3 tore down a bunch of German sedans in the 1970s to try to figure out why they felt so stable at high speeds.  IIRC Mercedes was running somewhere around 9 degrees positive caster in their (also IIRC) SLA front suspensions.

i just googled "GMT400 steering box frame" and found pix of rust around the mounting holes, and cracks where the LCA Mounts are welded to frame. 

In reply to Dusterbd13-michael :

It sounds like you have a frozen ball joint to me. 

​​Absent that, any chance all 3 boxes came from the same "lot"? 

I'd pop the pitman arm off on the box end and see if the spindles turn smoothly by hand with it up in the air, and how the steering wheel turns, engine on/off. 

 Had A Very Similar Problem When Upgrading A 57 Chevy Box, Bottom line,  the Pressure Hoses Got Switched,

GTXVette said:

 Had A Very Similar Problem When Upgrading A 57 Chevy Box, Bottom line,  the Pressure Hoses Got Switched,

if that is the answer, i'm gonna put that in permanent brain storage.

Re: hoses

No way to switch them on this one. Fittings are different sizes.

I looked for steering box mount cracks. None found.

No way all boxes could have been the same lot (well, statistically speaking) due to time between and different retailers. Most recent box was cardone. #1 was original and had play. #2 was masterpro from orielleys. It grenaded on the interstate (1/2 turn play either direction suddenly) #3 was unknown brand reman put in at a service station in pilot mountain. #4 (this one) is cardone. 

All the play seems to be in the box based in input shaft/output shaft movement. 

When i had the steering linkage and box out, i manually turned the spindles. They moved freely with minimal effort. They would not flop around though. If you stopped exerting force, they would stop moving. Both sides were checked like that, and felt similar. This was done at full droop.

The alignments are done at minimum bag pressure (10lbs) bags are used when towing/hauling enough weight to tuck rear tires to the rub point. Bags are aired back up to level truck at whatever psi is required. 

Is there any way that i havent described trying yet to check ball joints?

Saltydog: the issue has been present in varying degrees of severity since i rebuilt the suspension. In hindsight, i have been chasing this same problem for a year. It got dramatically worse ehen the #2 box grenaded, and has gone downhill rapidly since then. 

Steering, with the truck jacked up and weight off the tires, wether running or not, feels abnormally stiff. Compared to my duster or neon or mazda5.

Are All T R Ends on the correct side of  spindles,

OR you have Dropped Spindles did you Re locate the steering arms they must be level with the Lower control arms or Bump steer is Out of Control, Look at the web site to see if they offer a pin to relocate the arms.

OK, the abnormally stiff steering with no weight on the tires makes me think upper ball joints are binding, because they're the only non-DJM "linkage" part (a spring is a spring IMO).   Hear me out:  it is possible that the centerline angle of the UBJ taper in the DJM drop spindle is not the same as on the OE spindle, and the DJM UCA might mount the UBJ at a different angle than the OE UCA in order to work with the revised centerline angle.

you said :  When i had the steering linkage and box out, i manually turned the spindles. They moved freely with minimal effort. They would not flop around though. If you stopped exerting force, they would stop moving. Both sides were checked like that, and felt similar. This was done at full droop.

so at full droop the UBJ's may not be in a position to bind because at full droop the UCA is at a totally different angle than at ride height.

to test:  remove shocks and springs, then push spindle up so suspension is at ride height, then push spindle through left/right steering and compare the effort to what it takes to steer it at full droop.

In reply to AngryCorvair :

My thoughts as well, this sounds like a kinematic issue. My first thought at that list of aftermarket suspension equipment was that something was probably binding up somewhere, either in the control arms or possibly the steering linkage. 

The djm lower control arms and spindles are ADVERTISED to work with stock uppers. They are not reccomended to be used with one another due to scrub line issues. That being said I don't know of anybody that has ever actually done it other than me. Y'all are coming up to the same conclusion as me that it almost has to be in the ball joints at this point. Except for the play in the steering box which we know is an issue. Sound about right?

In reply to Dusterbd13-michael :

Maybe?

Do you have a set of stock wheels and tires you can test with?

just to make sure the scrub angles and such aren’t contributing to the issues 

Unfortunately, its on the only set of available wheels at this time.

You guys made me do some research differently than before. It seems, via forum posts, that djm lowers have the ball joints at an odd angle. Theres quite a few reports of ball joint failure (lower) when paired with lowering springs. Even though they sell them that way in a kit.

Think im going to try to call djm tomorrow between 9am and 3pm Pacific and see what they say.

 But i have a feeling that the parts cannon may get reloaded.....

Have you been flushing the system between boxes?

It's possible you have crap in the pump/lines that's going through and screwing stuff up. 

What fluid have you been using?

In reply to Crackers :

Yessir! I also have a filter on the return side. I have found no debris in it, however . 

Fluid is standing prestone power steering fluid.

Is there any way to check pump output without so.e sort of expensive tool?

In reply to edizzle89 :

see above

Less caster would make steering easier but would affect steering while driving.

Heck, some cas in the distant past ran negative caster.

do this step by step,

#1    Excess play at center.   Why

#2  Stiff steering.   No power steering   why

 #3 no return. caster should do this along with steering axis inclination .  

#4 I'm thinking that along with lowering, spacers, wide wheels just add up increasing the scrub radius    The lowering spindles can be suspect..    The control arms affect the instant center.  

 sorry if some of this is discouraging

In addition to everything above, with having been through 4 steering boxes, I’d think it’s safe to assume something (wide tires, alignment, etc) is putting excessive load on the steering box.  Any known swaps for something heavier duty that can be put in?

In reply to eastsideTim :

Not only are there not any swaps i know of, the only way to get a NEW box is roughly $500. Which is outrageous. 

I agree about the undue strain. I think whatever is the root cause of the issue is whats killing them.

The more i think about ball joint angles, the more convinced i am that they are the root cause. Or a defective product from the start.

Does the GMT400 have a similar kind of lower support bearing for the intermediate shaft that the GMT800 does?

https://www.amazon.com/gp/product/B004AI9SQA

Replacing this part fixed some really strange things that my 2007 Silverado 2500HD was doing.

Mine had also gone through three steering boxes, all reman (GM parts chain), none of them fixed the issue and one actively tried to kill me (binding up on the freeway).  I was considering a box from these guys, but haven't needed it yet:  https://redheadsteeringgears.com

No center bearing on the 400.

And redhead IS the only new option here. 300 box, 75 shipping to me, 135 core charge and return shipping to them for the core.....

A shot in the dark.  Rag joint?  I remember, you having an issue with it and wanting to go to a Jeep setup.  My daughter had an Altima that would give her fits with the intermediate steering shaft.  The steering would get Real Stupid on it.  Sprayed it with PB blaster to check.  Sure enough, steering went back to normal, so I replaced it.   Steering Shaft angle?  Might be wrong geometry due to lowering?

Did some light reading on the GMT400, something about an EVO sensor, don't know much about it.