As the former owner of a driveline shop I have many years of experience at building drivelines. These are a few things I leaned along the way.
Here are some very basic rules to be used a guidelines:
1. total length is from ctr/ctr of joints
2. 3" tube diameter is generally considered the minimum for automotive gas engines
3. 54" length maximum for gasoline which may require 3.5" tube in some instances
4. larger tubes need heavier wall thickness, i.e, 3"x.065 is popular but .083 & .095 are available, depends on the joint series, speed and available end yokes.
5. joint angle must be equal and cancel out each other.
6. 65" maximum length for diesel units - 3000 max rpm, usually 4-4.5" tubes
7. when replacing a driveshaft always have the builder use a tube & yoke [censored]'y which is much less $ than a tube and two weld yokes, This is because there is only one yoke to align and weld.
8. joint series cannot be mixed in any driveline
9. All yokes must be in phase
10. carefully assembled and welded drivelines do not require balancing which is a production consideration. Tolerances must be tightly held however.
When replacing a transmission the new one must have the same series of joint as the old one. So if the 4 speed has a 1310 series, (very common) and is shorter than the replacement tranny, uses a 2 piece driveline then it may be possible to go to a longer transmission assuming the new tranny also has a 1310 series and use a one piece shaft IF the OAL is still acceptable and angles are within specifications.
A complete new 1310 shaft might well be $200+ but a tube & yoke [censored]'y with a re-used slip stub shaft should be 25% less. Often u-joints can be re-used as well if they are in good condition, are carefully inspected and re-assembled.
Small dents do not usually cause concern and larger ones call for a tube replacement. Drilling holes in the dent and pulling them out will mean rust inside the tube, a no win situation.
These are all general information items and not meant to be specific to any particular vehicle. Most driveline rebuilders know their business and will not take advantage of a potential customer so don't jump to conclusions about them unless you have ALL the facts. That's good advice for virtually everything on the internet IMHO.
