HTML:
Is the gear the same on an 80s chevy 4x4
I believe the spline on our the steering box is a "3/4 x 36".
That means it has 36 teeth in theory. Sometimes there is a "missing" or filled in tooth, for assembly orientation, or sometimes a flat to act as a backup/failsafe for torque in case the teeth strip or the clamping bolt on the yoke loosens up.
The 3/4 would be outside diameter OVER the teeth (or major diameter), and may not be actually . 750"... it is likely about . 730 to . 745 so don't let that throw you. It is still considered 3/4.
It is used in many applications by most of the big 3... when looking for a mating I shaft yoke, make sure it does not have the flat section as I believe our trucks are a full splined shaft on the gear.
The mating yoke will likely have some teeth "missing" and will be at the major diameter in that area. This is done so the yoke will "squeeze" and clamp better. Missing teeth like this will fit fine.
It is best to use a NEW bolt of the same specs. It probably will be a M10 x 1. 5 and should be a class 10. 9 ... and likely 40 mm long. It should also have a locking patch... use loctite as a substitute if needed. Torque would be 36 ft-lb.
Since the I shaft has very little operating angle it won't matter much how the u joint or joints are phased.
When welding the upper end to the column, you should wrap the u joints in a wet rag to act as a heat sink to protect the beraings and internal grease seals.
I recommend leaving the rag coupling as part of the system... . it's function is to isolate pump and road noise from comming up the column... the steering wheel acts as a speaker and the sound may resonate.
Hope this helps.
Jay