Hello I will help you with your question,
If the bushing for the shift shaft is worn the shaft will move too much for the seal to be effective. The solution is to replace the bushing and the seal at the same time
I cannot access your previous questions at this time, can you please tell me the year of your truck?
There may be a groove worn in the shaft where the seal rides allowing the leakage, I mean the shaft moves up and down, if you cannot feel any movement we will have to look elsewhere for the source of the leak.
The pan will have to come off is the bushing needs replacement as the shaft will have to be removed.
I have been looking for diagrams to help with the bushing replacement but so far I have come up empty, if you can give me a couple of hours I will keep trying
The oilpan and the valve body will have to come off to replace the bushing. The valve body has check balls that WILL fall out when you remove it from the transmission,
away from their holes.
If you have never done this before I would NOT advise learning on this one to cure a small oil leak. Have it done by a Pro.
The bushing can be accessed in the case once the valve body is out
Let me know if you are determined to do this yourself and I will provide what help I can
Inspect the shaft for wear it can be cleaned up to give the seal a good surface to ride on
Find a general repair shop with an older tech that has experience with these transmissions, this is not a hard repair if you have done a few but those that have are mostly retired now, a trans shop should be alright also the owner usually is a tech that retired from turning wrenches to running the shop and has done a few in his time. A leak at the shaft is not unusual,
You are right having a shop repair this, they may try to sell you a complete rebuild, let them know upfront you are not in the market for that, some shops that is the only way they will do this job
Glad to help and thank you for using JA!!