It all depends on the failed part. If the leak can be repaired without a rebuild, then yes.
The repair on the transmission line will depend on where it is. If the leak is at a coupling then the joint may be able to be tightened. If the line itself if leaking or split then it will have to be replaced.
If it is leaking at the bottom where it sets into transmission--shouldbe an "O" ring seal
NO you dont have to rebuild it, you have to replace the seals and gaskets. it also helps to know what type of vehicle this is for.
look for the leak and repair it . I would do that before i thought about buying a new tranny.
When a power steering rack leaks you either have to rebuild it with a rebuild kit found at your local parts store or replace it completely. There is no quick repair for that.
Find the leak source and repair it. Usually the cause is cooler hoses.
The transmission will not work without fluid.
If it's oily, it's transmission fluid. You need to fix all leaks as soon as possible. Or you will have soon a serious bill for repair. If it's not oily it might be the coolant, you need to find the leak. If you don't do that you will get a bill but not as big as the transmission repair.
You can try to repair a small leak in a diesel fuel tank without taking off and welding by using specially made putty.
Determine the origination of leak and repair Could be transmission cooler line, seal, etc.
Roughly 500usd labor excluding parts
You have a leak. You need to find and repair the leak.You have a leak. You need to find and repair the leak.