The SUV had a small AT fluid leak, and I only noticed because the Reverse and Drive began to slip. I added about 2-1/2 quart of fluid, and for a few minutes, all seems to be okay until the Drive began to slip again. I looked under the car and saw quite a bit of fluid leaking. I dove home using the 2nd gear and driving no more than 40 MPH. Had the car towed to a Transmission repair shop and they fixed the leak, change the filter and added new fluid. Drive engages nicely, and all appeared to be okay until the RPM's went above 2,000; at this point, it did not shift into the next gear and the RPM rev up to about 3,000 RPM. I drove the car a few times, and this is what I have observed so far:
1. As mentioned Drive engages fine at first the once past 2,000 RPM, it revs up. I can shift manually to 2nd gear, and when it reaches about 3,000 RPM, the drives engage into another gear. I can also keep it in Drive and let the RPM rev up to about 3,000, and the next gear will engage.
2. Once the Drive engages in the next gear, I can accelerate but the RPM keep going higher, and there is no downshift. I drove it in the freeway at about 60 MPH, and the RPM was about 4,200.
3. At times I was able to make it downshift while in Drive by releasing the gas pedal and the accelerating.
4. The service engine light went on and I got the code P0744 with the following messages: a) A/T TCC S/V Function b)Torque Converter Clutch Circuit Intermittent.
5. I added a bottle of Lucas AT to improve shifting and slippage, and I saw a small improvement.
I am afraid to take to a shop and get the "need to rebuild transmission" recommendation, so I want to explore all options, and I am open to suggestions and recommendations.
Thank you in advance for reading my post and for any advice anyone could provide.

Here's the best, most complete write up on how your problem should be addressed:

2002-2wd-pathfinder-with-p0744-ses-and- ... 07566.html

I bet the "shop" disconnected one or more of the solenoids attached to valve-body - inside the pan.Mistake?
Or on purpose. There are steps, procedures, or diagnostic methods coupled with codes to point to which relay is suspected - may be going bad too? Don't forget to check/reconnect ANY exterior harness conn's of entire transmission!!

Thank you for your replies.

is it slipping or is it just not shifting at the correct RPM? I had a shifting issue where it wouldn't shift into overdrive and it was the TCC lockup solenoid. if your trans is slipping then most likely it needs to be rebuilt. Running it low on fluid most likely damaged it.

There is no slippage at all. 1st and 2nd gear appear to shift at the correct RPM, but 3rd gear shifting varies and sometimes I have been using manual shifting to make a smother shift for the 3rd gear.
The 4th gear does not engage at all; I drove it in the freeway at over 5,000 rpm and would not engage.

Papagayo, did you ever find a solution?