There have been modded SS's that have gotten F35 -> F23 swaps. Part of that may be availability though. Maybe someone knows what breaks on the F35's. They don't break easily, tho. Certainly a lot stronger than the automatics.

 

The interwebs refer to the F35 as "a nightmare" and the F23 as far superior, cheaper and more available. The shift fork arrangement is cited.
I never heard of a problem on this site. Sweden vs Italy.

 

Reliability varies with ratio. The 4.05 F35 in HHR SS is fine, and available w/ LSD. Most of the problems I've read about when they break behind heavily enhanced boosted 2.0's in Cobalts w/ 3.82:1, although I've heard of a few HHR turbos getting an F23 swap.

Part of the appeal of the F23 is price and availability.

But back to the OP, why check the level? Is there a problem?

 

my transmission start sound in 5 and 4 when released the gas pedal