HELP (71 Stepside C10)

[Chris_71_C10]

Need some help. I have tranny leak where the speedometer cable connects to the trans. I have changed out the gear housing and put on a new cable. I used RTV as well and within 10-15 mins I have trans fluid on the ground. I have tried everything, both parts are new. The cable is new from Chevy Resto and gear housing is from Chevy Dealer. The O-ring is new as well, any ideas to help me get this resolved? Thanks in advance for any help out there.

 

[66 KUSTOM]

check the seal on the gear housing where the the cable slides in

 

[Chris_71_C10]

Tried that and still did not work. Tried several new seals and two gear housing from the chevy dealer. It stopped leaking for about a week and started back as of today.