Torque converter toast?

It's been a LONG time since I've posted here but hopefully someone can answer this definitively.

Just finished taking the XJ back down to 35s on D44s and 4.88 gears and am finding that it is a gutless wonder. First gear is OK but there is virtually no power in any other gear. I have a manual TC lock up switch and it is locking and unlocking the converter. When stopped in gear, you can feel the coverter grabbing and you have to have good pressue on the brakes so you don't inch into the vehicle in front of you. It also has a fairly susbstantial vibration when driving with TC locked and unlocked. I thought it was a worn rear slip yoke so I changed that and it made no difference. I think the TC internal clutch is hanging up which would explain everything. Thoughts?

Try this:

1. Let the Jeep sit overnight so the tranny fluid temp stabilizes at ambient temp.

2. Do Not Start The Engine. When it is stabilized, remove the dipstick and see where the fluid level is. It should be around the "MAX" mark. If not, add a little ATF until it comes up to the MAX line.

3. Set the Parking Brake. Start the engine (do not shift through the gears). Leave in PARK.

4. Immediately check the fluid level on the dipstick. It should have dropped down to around the ADD mark on the dipstick. If it disappeared off the stick, you're a tad low on ATF. If the fluid level did not drop to the ADD mark, either the TC is defective and/or the transmission oil pump is weak.