Trans wont shift into gear

[14SWTahoe]

I changed out pans to a high volume one, nothing else and now the trans wont shift into any gear.

Only thing I did was drop the y-pipe, disconnect the front drive shaft and drop the pan, put new one on and refill... what gives?

Fluid level is correct, no lights on the dash

 

[Wake]

That's strange, haven't seen that before from a pan change.

Did you change the filter also, not sure if a shallow pan is stock but if you moved to a deep pan you also need the right filter so it sits lower in the pan.

Possibility that the filter fell out of the valve body during pan install?

 

[14SWTahoe]

The PLM pan is made to use stock filter, and i made sure it wasnt loose before reinstall.

So i checked the fluid level again after trying to shift into gear a few times and it was barely on the dipstick. The first time i checked was only after starting and ideling.

Between dropping the pan and refill i let it sit over night, got too late to continue, maybe that much fluid drained out of the valve bodies/TC while pan was off?

Bought 3 more quarts, see what that does.

Is there some safety on these trans if the fluid is to low it prevents any damage by disabling the trans? Very surprised no lights on dash....

 

[14SWTahoe]

so it took 10.5 quarts, the upgrade pan is only 2qts larger than stock (6qts). That would mean while sitting overnight it lost an additional 2.5 qts.

This fixed the shifting issue, shift fines, low on fluid.