'71 K5 TH350 Blowing Fluid on the Interstate. Help!

[badpeanut]

I was going to visit relatives for Easter and when I was about 20 miles from my destination I started to smell tranny fluid. I pulled over to find ATF dripping off the passenger's side of the tranny. I checked the fluid level which was good, where the kickdown cable and cooler lines meet the tranny it was AFT-free, the pan bolts were tight (not leaking here), but when I took off the dust cover it looked as though it was possibly leaking out the input seal since there was a very fine film of ATF on the back half of the torque converter? The K5 made it into town, but I used my entire quart of ATF in the last ten miles.

I was bucking a strong headwind the entire trip. I've never had any problems with this tranny before and recently serviced it. I didn't have time to do anything with it over Easter due to family commitments, so I'll probably have to trailer it back home when I can get some time off from work.

What would cause a TH350 to suddenly blow like this? Do I have to look forward to pulling the tranny to replace the input seal? Is there something easy I'm overlooking?

Thanks in advance,

Wes