transmission probably overheated now has a leak
 

96 f350 auto. I went camping, drove 300miles towing an 4000lb trailer. at the end of the drive there was about 20 minutes of forward and backwards up a hill trying to squeeze the trailer into a tight spot. I got things parked and unhooked the trailer. When I went to move the truck forward I noticed that it wanted to roll backwards while in drive. Gave it some gas and it surged forward then stopped then surged... Thats when I found the pool of ATF fluid and the entire bottom of the truck was covered in it.

I couldn't see any obvious source of the leaks. I did find that the fill tube on the dip stick had a big crack way up high though. That was just enough to stop me from filling it. I bodged that together and I ended up adding 7 Liters of ATF. That was enough to get us home but near the end of the drive it started feeling like it was slipping on hills and under load again. Parked it and there are a few small drips under it. A tow from where we were would have cost the same as the truck is worth so I'm happy to be home.

THere is a rubber plug that seems to have some drops, but I wouldn't be surprised if it's leaking elsewhere.

Anyways Is there anything obvious that should be checked? I've spoke with a few people here who have had transmissions rebuilt and they've all been 3-4 thousand. I was already worried that the truck was getting old for how remote we end up and the engine wasn't really feeling very strong. So I'm sort of leaning towards letting her go and checking out a new to me F150, hopefully something a tidge smaller but with far better then the current 8MPG I'm getting. I'm wondering what every here would recommend? I like my truck but I'm a tightwad is the main reason I haven't replaced it.

Your torque converter seal is going bad. The heat deformed it and it lost fluid. At first, usually, when they cool they will seal back up, but eventually, it will leak all the time. Transmission R&R is required to replace it. The factory seal is a gray rubber, do not put one of those back in. You want one that is either black or blue rubber, those can take more heat.

Thanks for the info even if it is bad news. Oh well now to decide on the new/new to me...

Bad news?????? Since when is a simple seal replacement worse news than a complete rebuild?

don't you have to drop the transmission and get that torque converter out to replace that seal?

Yes but there is no need to rebuild the trans, which would be quite a bit more $$$.

Like the others said, you might not need to rebuild the trans, just replace the front pump seal, torque converter, and put a transmission cooler in so it doesn't happen again. Still not cheap, but cheaper than a new transmission. I had to go through the same thing just a few months ago, my trans didn't slip but it puked a LOT of fluid whenever it got toasty.

You only need to replace the torque converter if the surface that the seal rides on is damaged. If it's fine I'd put it back in.

if your truck is 4wd,shift into 4lo when crawling around/backing up trailers and going up and down steep hills to park etc.there's no need to lock the hubs in just to make use of the low gears.the trans will hardly need to work and keep much,much,much cooler.
if your 2wd.......well put 4wd on your list for the next truck.;)
i think transfer cases should come on all trucks.2wd and 4wds.t-cases are invaluable.

Yep. Love having manual hubs which gives me the option of 2wd Low. Works great with a trailer.

I'm getting the same thing. I'm planning on replacing the seal. I read somewhere that there's an upgraded seal, but I can't find a manufacturer. Or should I just look at a local parts store for a black or blue rubber one?

Look for one made from a material called Viton. That's the good one. I don't know about the different colors on the seals.

I've seen them listed online at www.transtar1.com

Thinking about it more, I'm not sure if I want to pull the whole tranny out to replace the seal. I don't have a good spot to do it at home, and mine is a bit of a beater work truck.

On the other hand, I'm thinking to add an aftermarket tranny cooler instead. Less work if it'd save from having to replace the seal.

Sorry, didn't mean to hijack the thread necessarily. Figured since I'm getting the same thing as the OP, it was still relevant.