Recently the pedal of my DigiTech Whammy has started jamming.

It gets really hard to push down/up and starts shrieking like two pieces of metal grinding against each other.

I'm guessing it needs lubrication of some sort? Any piece of advice on this?

Could you post couple of photos of the problematic part on the pedal? This would help.

Without photos, I can only recommend that you localize the problem and see what is the cause of this. Metal parts could be distorted in some places so they cause grinding, but it could be other reasons not sure. Before lubricating, try to see if the metal casing/parts are all as they should be. If you see some part a bit distorted and getting in a way of some other part, try to take pliers to straighten the metal. Then apply some lub if needed.

That happenned to my crybaby once, I took it to my local shop and they put some greasy witish stuff on it to lubricate the hinges/mechanism... unfortunately I don't know the name of it But it's fixable

I had the same problem with a POD xt, I went to the shop and they fixed it for me, maybe it works for you too

Thank you for your replies.

I'm not gonna take it to the shop as I bought it from thomann.de and I feel like I can fix it myself.

No metal parts distorted. I seem to have located the problem to the heel of the pedal (where it's mounted on the chasis).
So either the bolts have tightened too much or they need lubrication.

Still no one knows what kind of lube you use for pedals?

I will get some tools to fix it from my dad...

If its just a metal part, you could use good old WD-40:

WD - 40 - The Solution to many of your lifes Problems

Problem fixed!

Didn't need lube, just had to loosen the bolt. Aparently it got tightened from use O.o

Glad you solved it! This reminded me, I have to put some lube and clean my wah pedal...Its a mess