Chevrolet Repair: 1988 Chevy 1500 tranny, 1988 chevy 1500, rear brakes

Question
The rear oil seal on the transmission is leaking. I discoved this after work when the truck started making a sound like the rear brakes were dragging. It felt like it too except the it only happened in gear. 1st gear seems to be the worst and it sounds RPM dependent. I don't know what transmission is in it, but it is RWD and has a 350 engine. What would be the best option here? Would fluid flush, filter, and new pump be the answer? Or should I replace the whole thing? I've a lot of engine work and replaced a couple transmissions, but never worked on them or diagnosed them.

Thanks a bundle,
Mark

Answer
Hello Mark,
Just a tad more information would help, as in, automatic or standard trans.
I almost assume it is an auto.
A standard doesn't have a filter or pump, and if it is an auto, replacing the pump is quite deep....much more than filter replacement.
If it is an auto, and making that much noise, I think some extensive repairs, like overhaul, is in order.
Well...actually the same for a standard. Especially if the noise is inside the trans, and caused the rear seal leak.
Van