Steering Box Spline questions.

[iflan84]

I'm wanting to put together a steering shaft for my 78 El Camino. I'm having trouble with selecting the correct DD to steering box u joint.

All of the aftermarket shafts that claim to be bolt in have a 3/4" 30 spline connection yet all the rebuilt/new steering boxes I can find for the Gbodies are 3/4" 25 spline boxes. All the direct replacement rag joints seem to be 3/4" 25 or 26 spline. Do I need to upgrade to a box from a different application? Shaft is 1"dd on one end and 3/4" DD on the other.

I was able to find the correct joint for the steering column side of the connection.

Any advice is appreciated.

 

[Rt Jam]

What is " DD Iflan"?

Most of the aftermarket shafts have 2 universal joints. So they can articulate but most of them can not account for length change.
The OEM upper joint not only articulates, it slides in and out to accommodate for length change.

In the garage, I'm sure length change is not required but once our cars hit the road. The steering box mounted to the frame and the steering column mounted to the body will move around requiring length change. Ignoring this fact has to be hard on bearings in the steering box and the column.

 

[iflan84]

What is " DD Iflan"?

Most of the aftermarket shafts have 2 universal joints. So they can articulate but most of them can not account for length change.
The OEM upper joint not only articulates, it slides in and out to accommodate for length change.

In the garage, I'm sure length change is not required but once our cars hit the road. The steering box mounted to the frame and the steering column mounted to the body will move around requiring length change. Ignoring this fact has to be hard on bearings in the steering box and the column.

I'm going to be using an aftermarket shaft that is a Double D style. I need the correct u-joint to connect the shaft to the steering box. I found the correct u-joint to connect the Double D shaft to the steering column.

 

[iflan84]

What is " DD Iflan"?

Most of the aftermarket shafts have 2 universal joints. So they can articulate but most of them can not account for length change.
The OEM upper joint not only articulates, it slides in and out to accommodate for length change.

In the garage, I'm sure length change is not required but once our cars hit the road. The steering box mounted to the frame and the steering column mounted to the body will move around requiring length change. Ignoring this fact has to be hard on bearings in the steering box and the column.

The shaft I want to get is telescoping.

 

[Ribbedroof]

The 78 box shaft is different than every other G body box, probably make life easier to switch to a 79+ box.

Be aware that the hose fittings changed from inverted flare to O-ring style for 1980 model year and beyond

If you search 565bbchevy posts, he recently posted what parts he used on building a shaft

 

[iflan84]

I think I found the problem and parts I need.

Pretty sure the issue me being dumb.

I'll post an update once my parts come in and I test it.

 

[Rt Jam]

The original shaft is also telescoping but it's very hard for it to slip. It is meant to collapse in an accident. Just make sure your aftermarket shaft is not like that.
It must be able to easily slip like a factory slip joint.