are you checking it with the truck running in park or neutral?? it has to be running to be properly checked. it sounds like u are checking it with the truck off...
I check it all the time, running, through all the gears, and even had a buddy hold the brake while i check park reverse neutral d 1 2. I always check it when its cold and its on the dipstick (cold) side and when it warms up its always the same no matter if i added fluid or not.
Like i said. My tranny had a bad pan seal and it leaked a lot when it got hot. The fluid level appeared normal. Then my tranny wouldn't go into forward gears when it got to 160* for the first time in a while. Check fluid when this happened and it appeared normal. I added 1 quart of fluid and let it cool down to 140* and drove it home normally. Then five months later with the same leaky pan and reaching temps 160-180 normally it did it again. Checked fluid seemed fine. Let cool down was able to drive it home.
(Every time i drove it during those 5months between my tranny problems. I reached temps up to 180* and didnt have a problem.)
So after the 2second time I decided to fix that leak. Fixed leak and I removed around 8+ quarts of tranny fluid (atleast 8 in my drainoil collector and who knows how much missed the pan when taking the bolts out (no drain plug). So i fixed the gasket and replaced the filter. I added 7.5 quarts of fluid back because thats what the pan is marked. Checked the dipstick and it said it was fine (running for about 10 mins after change) Drove it around and it was fine and I let the truck sit over night and checked it cold to make sure it was on the stick. So 2 weeks later the tranny got to 180 and decided to not go again. Added 2 quarts of fluid and its fine... And thats where I am now.
I don't know whether my problem is a bad tranny (It shifts fine, and when I took the pan off nothing smelt burnt and nothing in the pan. Just a little sludge and fuzz on the magnet) Or if I never had the proper ATF level, and it was to low and when it got hot it became to thin(?) and wouldn't function within the tranny properly.
So there's basically another sum up of whats happened. Sorry if I have any typos its kinda late and I'm tired. All i really wanna do is upgrade my cooler (still wana see a pic of a true 96 stock cooler) and try to kept my temps below 160* which seems to be bad luck.