what does it mean if your cassette deck playback and recording sounds warbly?

Troll?
How does telling truth equate to that?
If you don't want to hear that the deck is more likely to be the problem than the tapes are, just get used to it.
Instead of juvenile name-calling.
Abrupt language is NOT negative.
Why did you buy a new deck anyway?
Hopefully to insure against manufacturing defects. Too high a price to pay for me.

@fuzztone the reason I bought a brand new deck is because i wanted a perfectly working deck. didnt happen

i dont want a moron on my thread dissing stuff I enjoy.

You said something about juvenile name calling; he said "sucks" twice.

I'm the same way with some things. I was looking at a NEW Tascam Cassette. The wife has a slough of her old cassettes. 

A little update too.. It's not your thread.. BUT it's nice to think that, just on loan, kinda', sorta'.

The words are yours right up until you hit "Post You Response".

Regards

Seen the specs and the unit has a pitch control for the tape function. Check what happens when engaged or not. Otherwise what MC said. If nothing changes send it back.

G

"...@russ69 ok man. stop trolling my threads with negative comments. You are being a jerk..."

Sorry but a new deck should not do that, perhaps it should go back for repair/replacement.
EDIT: The problem today with a cassette deck is that most units will be low cost units with low cost drive mechanisms. I hope they can fix your issues because you are still trying to enjoy your cassette collection.