Whirring hissing sound is gone. Go figure. Still takes it's time dropping into gear after sitting a while though. If there's a diaphragm in the pump that's failing I'd like to know. I would think there would be an impeller. I'm just guessing. I'm not much of a bench mechanic. Mostly just remove and replace. Which is not easy to do with an auto transmission when you're working off a dirt floor or even a piece of plywood. I'm keeping an eye out for a piece of steel that I could roll the jack around on. I'm just a poor mountain man in the middle of nowhere. Once enough fluid leaks out around the shifter seal I'll try some of that Lucas product. Maybe it will even fix my shifter seal leak. I'm a big believer in Marvel Mystery Oil but I don't think it would help here. Thanks.

 

I just looked at something online. I'm going to put a new modulator on it. I'll let you know.

 

i like your truck

 

I'm back!!!
I'm getting used to it, been cutting firewood, it works fine besides being slow to drop into gear the first time after sitting for a while, so I might not do anything, but it still makes me crazy.
I talked to a mechanic friend and he says the whirring sound is cavitating because of air in the lines. I didn't mention before that I have an aftermarket transmission cooler behind the grill. Any suggestions for getting air out of the system? What really drives me nuts is the inconsistency of all of the symptoms. Sometimes there's the whirring sound and sometimes there's not. Most of the time it takes a minute of high-idling it before it will drop into gear after sitting for an hour but sometimes it drops right in. The other day it sat for a couple of hours, it dropped right into gear, I moved the truck 50 feet, let it idle while I got out for a minute so it wouldn't "lose it's prime" and when I got back in I had to high-idle it again before it would drop in again!!! I guess that "losing it's prime" is a good way to sum up the problem. I read somewhere that there's a little check valve in some C6's and that it could be stuck but I can't find again where I read that.
If you guys have any more ideas I would appreciate them. Thanks in advance! It usually takes me a while to reply.