2001 GMC Yukon denali lost all gear

Ticking noise, kind of like a really loud clock? I would say the culprit is the electronic solenoids in the transmission are malfunctioning. If you just had it replaced, it should still be under warranty. Most rebuilt units come with at least a 3 month warranty.

Quick note. It is possible that some of the flex/convertor bolts have loosened, making the noise, but it would still drive. Have you checked the fluid level?

GuruBT3LW... yes sound like a loud clock. You think if the filter inside the transmission came loose? would it cause all gears not to work? The fluid in the transmission is a little high

Well, at least it has fluid. Which is a good start. The filter coming loose is possible, and could stop the flow of fluid to the internals, as I'm sure you know an automatic without enough fluid/fluid pressure will do nothing. But I'm leaning more toward another internal problem, such as the electronics (the solenoids) or a bad/clogged fluid pump. Sometimes the rebuilt units will need parts from the old transmission to be installed, like the solenoid pack. The ticking noise is what's concerning.

The A and B solenoid was replaced brand new. But i dont think that the problem. But the ticking noise could it be a cracked flex plate? Im thinking it could be a bad torque converter?

It could be the converter... But if the ticking is constant, or increases with rpm I would lean more towards the bolts that hold the flex plate on coming loose. However, the truck would still move in that condition, probably with a decent amount of diveline vibration included. Something is really wrong. An incorrectly installed converter could do that. If it was on the crankshaft, and then the trans was installed it won't mate correctly, but there would probably be fluid dumping out everywhere in thst case. It's a genuine mystery. Do you still have a warranty? Was the work done by your regular mechanic or a transmission shop? Either way they need to look at it. Without seeing it in person, I'm honestly out of suggestions.

It is possible that whoever did the transmission got in a hurry and used only 1 torque convertor to flexplate fastener. It may have come loose causing the ticking sound before coming undone altogether. Check to see if the flexplate is still bolted to the torque converter.

GuruBT3LW the transmission was redone out of state. Thats a far drive. Bob... could be a chance that the torque converter bolt could be loose. But when i start the motor. The torque converter and flex plate move together. If it move together i shouldn't lose all gears. Could it be tge transfer case? But if the transfer case goes bad it would Grind. So i dont think is the transfer case or could it be the pump in the transmission? How can i find out?

You'll have to get it up off all 4 wheels to check the tcase, I would read some 4x4 forums about the actual procedure, as I have never had an issue with any tcase in the vehicles I have had with one. As far as the pump..... With everything still in the truck, there is only one way. You will have to back one of the trans cooler lines on the radiator off, not remove, just back it off enough to let fluid out, and while the truck is running see if fluid is being pumped out. If it's pumping, the problem is deeper...

Thank you i will do that and keep you guys updated

So today i unplug the transmission line from the Radiator no Fluid came out when i start the engine. So i think the pump is out. Cause it be my torque converter? Or do you guys think is the pump?

Update.... it was the transmission pump. I drop the transmission and put in a new pump. Works great.