Transmission problem with my 1996 Jeep Grand Cherokee

Ok, So I know this is a cnet car tech forum, But I figured their is a lot of great people who always give great advise. So let me explain this situation that has came upon me.

For around 6 months I noticed the (Automatic) transmission in my Jeep was going bad, Pump wasn't kicking on and the tranny was slipping and dropping hard in and out of first gear. So 11 days ago my 1996 Jeep Grand Cherokee limited (5.2l) broke down (Transmission dropped) while my wife was driving home from work. I had the Jeep towed back to our house and started making phone calls. I called a Family friend who is a phenomenal mechanic. He advised me the best thing to do is to replace the transmission with a used tranny from an auto salvage yard.

The following Monday, went and picked up this used transmission, Paid 479.50 after tax , The auto salvage business stated it came with a 30 day parts warranty.
We then headed back, and he started immediately to remove the old tranny and install the new one, It only took him 11 hours from start to finish to complete the daunting task. after 9 quarts of transmission fluid and a new filter/gasket, I test drove my Jeep. It ran great and shifted awesome. I was pretty please to say the least.

The following day, I noticed a small "chatter" when it was shifting from First to Second. Almost like it wont shift into second if your not giving it enough gas, but will shift hard when revving the RPMs to high. If you are going the perfect speed with the perfect combination of speed and RPMs it will shift OK. It has been doing this every time it shifts now and feels to me like it is getting worse. I constantly check the fluid to make sure the proper amount is in, and also look for bubbles or metal shavings, Nothing out of the ordinary in the fluid. All of the other gears/clutches shift great.

Funds are getting tight, I'm leaving for a 2 week California vacation in a few weeks and I have no more money in savings to do anything with the transmission at the moment. I could possibly come up with the cash for labor to have my mechanic friend remove the old transmission , then take it back, hopefully find a new replacement , then pick it up , then have him install the new transmission. But that is highly unlikely right now.

I'm sick over this whole issue, Basically, If you were in my situation, With funds low ( One vehicle family) What would you do?? , Leave the transmission in or remove and try to replace it. Since the Jeep is our only vehicle, we would be without a vehicle until the problem was fixed.

Thoughts Please ?