transmission problems

[Hunter45UT]

4R100 trans issues (211K miles); New to the site and looking for some advise concerning my transmission. The trans is leaking fluid between the pan and gasket. Over the past two months I have tightened the bolts three times since I replace the gasket and the filter. I added 1 qrt of Merc V each time . Additionally, I am experiencing rough shifting between 3rd gear and overdrive. Once the trans warms-up about half the time the OD light starts blinking. Prior to the OD light blinking the truck shifts in and out of OD. The RPMs shoot up about 500 RPMs. The RPM needle appears to bounce between 1200RPMs and 1800RPMs. Note I drive 12 Miles to work. Could this be a Valve body issue? The last time I towed a trailer (3000lb) I experienced the same symptoms. Does this sound like I am looking at a rebuild?
Plugged in my OBDII code reader and came back with no codes, passed every thing

[jesilvas]

What kind of code reader? Not all of the can read codes off these.

What kind of gasket did you use on the trans? Shoulda been a reuseable one?

[7.3550Duty]

sounds like your trans is starting to show some signs of a needed rebuild. Maybe torque converter going out and some of your clutches are started to show some wear. I mean you do have over 200k on it. Take it to a local trans shop and see what they have to say. I mean you could put the money into your valve body but that aint gonna fix your torque converter if it is garbage.
Make sure if you are going to rebuild it, always have the lines flushed and trans cooler flushed out. Wouldnt be good if you bypassed that and your cooler was plugged solid

[Hunter45UT]

Thanks, for responding to my question. I found out the code reader I used is not capable of reading advanced coeds. I hate to admit it but I think your rigt looks like I will be rebuilding the transmission

[CT Performance, Inc.]

If your thinking about a performance trans..we have the best price on a BTS to your door..PM me if I can help