Hey latief. Bummer dude. I feel for ya. If it ain't one thing, it's ten, huh.

Best I can determine is this trans (722.3) can be reasonably expected to go about 140k on average before it starts getting 'tired'. Slipping in reverse is the classic symptom of 'tired', again based on what I have read. I will send you some information I have gotten elsewhere on this. I will send you a PM.

If you want to R&R the trans yourself, you can get a rebuilt from Peter Schmid for about $1500. That will save you about $1000 to $1500 since an indy is going to charge $2500 to $3000 for this job.

There are some good write-ups on the forum here on trans R&R's. Here is one of them:

http://www.peachparts.com/shopforum/showthread.php?t=267415

You have to read down a ways to get to the info you need.

Look for a PM from me shortly. Pete