I have a leak on the drivers side of the radiator?

If you have a leak on the driver's side of the radiator where the cooling line goes into the top of the radiator, it's likely related to the transmission cooler lines. In many vehicles, including the 1999 Chevrolet Suburban, the transmission cooler lines run through the radiator to help cool the transmission fluid.

The "bolt-like apparatus" you mentioned is likely the transmission cooler line fitting. This fitting is threaded into the radiator and sealed with an O-ring or a gasket. If the fitting is loose, damaged, or the O-ring/gasket is worn out, it can cause a leak.

Here's what you can do to address the issue:

Check for loose fittings: Make sure the transmission cooler line fitting is tightened properly. If it's loose, carefully tighten it without over-torquing, as the radiator's fittings can be sensitive to overtightening.

Inspect for damage: Examine the fitting and the surrounding area for any signs of damage, such as cracks or fractures in the radiator housing or the fitting itself.

Replace O-ring or gasket: If the leak persists, you may need to replace the O-ring or gasket that seals the transmission cooler line fitting. This will require draining the transmission fluid, removing the fitting, and replacing the seal.

I apoligize. I thought you were talking about the part that is inside the radiator. That part has a big nut that attaches it inside the radiator and will leak coolant externally and it looks like the nut can be tightened or resealed but it cant. I try to answer as accurately as possible with the information I am given. I assumed you were leaking coolant, not transmission fluid. My mistake. I should have asked you for a better explanation. We do try our best to give fast accurate answers and unfortunately something like this happens. Again I apoligize. Tim