Lowering my dually?

Driveline angle doesn’t matter, it’s the angle of the pinion that needs to match the angle of the transfer case output shaft. If the suspension is lowered In a way that keeps the rear axle unrotated compared to its original location it should be fine. Changing the hanger length on one end of a leaf spring can cause issues. Removing blocks between the axle and springs should not.

Changing axle height changes the drive shaft angle between the transfer case or transmission and the axle. This anle will be exaggerated even more once the rear loaded down. The OEM accounts for loaded and unload ride heights when designing the drive line angle if you go too far out of specification, it will cause joint issues. if you look at some suspension lift kits made for trucks, they will actually have a wedge that is inserted between the axle and springs to lessen the joint angle after adding the lift. You can argue that this is more of an issue in the front to due to a shorter run, but it also happens in the rear.

Read up on proper pinion angles and drive line vibration before dismissing what happens when you change ride height.

Bedlam wrote:
It will change your drive line angle. If you are getting considerable squat from your load plus lowering axle height you may find u-joints failing under heavy load or joints binding during spring compression. Lowering the rear too much without adjusting the front may make the truck nose high when loaded - This will affect your steering and lighting.

By your logic, putting weight in the bed will change the driveline angle.

Removing the spring spacers and leaving the bumpstops in the same place does not change the range of the factory suspension. In other words, the "driveline angle" that is created by moving the spacers is the same as putting some weight in the bed and compressing the springs.

The driveline angle necessary to bind the u joints in these trucks is in excess of 30 degrees, perhaps even in excess of 35 degrees. The factory driveline angle is a single digit, probably in the range of 3-5 degrees with the rear suspension completely drooped. Also, moving the rear axle straight up and down by moving those spacers is unlikely to make even a measurable change in the driveline angle at rest.

Don't take my word for it, though. Download an angle finder app on your phone and you can see for yourself.

Where you got the idea that an inch change in ride height was going to cause driveshaft binding is beyond me. Whoever told you that was feeding you nonsense.

The current generations of trucks are way too tall and there are far greater consequences from not lowering them (bedrails getting hit by the trailer, ride height) than from lowering them.

Bedlam, how does simply changing the bed gap change the drive line angle? Transmission height and axle height don't change?

It will change your drive line angle. If you are getting considerable squat from your load plus lowering axle height you may find u-joints failing under heavy load or joints binding during spring compression. Lowering the rear too much without adjusting the front may make the truck nose high when loaded - This will affect your steering and lighting.

I'm assuming that lowering the unloaded bed height means lowering the towing height. Is that not correct?

parker.rowe wrote:

ACZL wrote:
I removed the aux spring hangers so the springs wouldn't hit them w/ the 5er attached. Tho the truck may squat some, I don't get whammed when the truck goes over a bump and susp is trying to go back down if that makes sense. The suggestion came from posters on here.

That might make it lower if you are on the overloads when it is hooked up, since as you said it will squat more.

But it won't change the unloaded bed height.

Your right. I was under the impression Dave wanted his towing height lower.

Super_Dave wrote:
Are the 3 spacers under the spring pack what can be removed?

You do not remove them you move them to the top of the spring. Down side it is the caliaper bolt can not be removed.

^ Yup. Those are them. That'll do a decnwt reverse level like you're looking for without sacrificing any capacity.
Don't remove the upper overload contacts. That's not a good idea for your application.
(Nor does it provide any change in ride height until the truck is sacked out, but if it's sacked out, you'd want the extra springs)

Are the 3 spacers under the spring pack what can be removed?