Transmission Trouble

This is my first post here, hope someone can help, my 90' 4runner has serious Tranny problems. For awhile now its been slipping in reverse (I know I should have flushed the unit or gone in for service, I just kept putting it off) well it is now pouring fluid out of the front, seal my options seem to be

Attempt to have it serviced (not sure if it can be repaired, but I believe the cost will probably be in the at least a $1,000)

Rebuild ($3500+)

Put a used one in ($650 parts/$500 labor)

any suggestions? thanks!

It just depends on how much the car is worth to you. A tranny tune-up will not fix a slipping reverse. Rebuilt or used, get a radiator too. Or use an aux cooler and bypass radiator cooler.

The problem with a used one is, you don't know how bad it is. If you plan on selling the vehicle do the least possible to get it to run half way descent and get what you can for it. If your Runner is your baby, like mine is to me, do the job the best you can and do it right. Sounds like you've been neglecting her. I have a buddy that had Totota install a good tranny in his Runner, it cost him somewhere in the vicinity of $3,000. I don't think the tranny was new but it did come from Toyota and they did the work and he's more than satisfied. My pops had his Toyota tranny rebuilt by a mechanic who claimed to be a Toyota tranny guru, that cost us about 2 grand...big waste of money. My bro is having shifting problems with his '90 Runner, same thing, I think he serviced it once when it was new and never again. He's looking to sell it soon.
Shop around. Cheaper doesn't mean you're getting a better deal and expensive doesn't mean you're getting better service. As much as I hate referring people to the dealer, sometimes it's better. It doesn't hurt to ask for a quote. Good luck and do your homework.