Bicycle Mechanics - Chain Slip issue?

I have Campy 10spd on my cross bike and seem to be having some chain slip issue. I've replaced the rear derailleur, chain, crankset, took apart the freehub and cassette which I then cleaned and put back together and still getting what feels like the chain slipping very shortly when I put some force on the pedals after coasting. It's a lot better after replacing the rear derailleur since the pulleys were hosed, would do it all the time, it now only does it after coasting and then start pedaling.

Anyone have any suggestions on what else to try?

Ok, we have to separate the types of chainslip, possibly by degree. Since it happens only after coasting, my first guess is that there's a lag before the ratchet's pawls re-engage. We usually see this when people use grease on the ratchet. The springs are very light, and grease behind the pawl can act like glue and delay them in the retracted position for a bit. The solution, is pull the freehub off again, clean up the pawl assembly, oil with a sticky oil (like Chain-L, or Phil's) and reassemble being sure the spring is working correctly.

Or the chain may be slipping over a worn sprocket. This is common with new chains and old cassettes, but usually only happen under load, and has a very specific sound and feel. It could also be that you have a burred tooth that the chain hangs on sometimes, or a stiff link, but these would be fairly consistent rather than only after coasting.

Lastly it could be a simple RD trim, or hanger alignment issue, so that's something to check too. Especially as the RD and pulleys were worn.

It's a new chain and cassette so I think we can rule those out.

As far as the freehub goes, I always assumed I was supposed to make those nice and greasy, actually I thought just about anything that has metal to metal contact should be nice and greased up. Should I remove the grease and only use some oil where the pawl assembly goes into the ratchet?

Indexshift details on the faces of the cassettes , cause Ghost half shifts,
where the chain is carried up on a ramp made to get the early shifting the engineers created.

if the cable is not spot on in adjustment. and check dropout eyelet alignment
the foundation of the whole deal, But..

Not being in front of me, another Blind Guess , but an educated one.. :D

Yes, as FB said - oil not grease anywhere the pawls travel.

As far as the freehub goes, I always assumed I was supposed to make those nice and greasy, actually I thought just about anything that has metal to metal contact should be nice and greased up. Should I remove the grease and only use some oil where the pawl assembly goes into the ratchet?

Yes from your description it seems that the grease is too stiff for the pawl spring, and delaying rebound and engagement. Ratchets need only the lightest of lubricants because they never move under load. When engaged (under load) there's zero movement and therefore no need for lube. When coasting, there's friction, but only as related to the very light force generated by the pawl spring(s).

So there's never a need for anything heavy. The only condition is that you don't want the lube spinning out, which is why you want a heavy sticky oil or a thin film of a light (not sticky) grease.

ok, great guys, thanks for the help! I'll try this later tonight and see if it helps.

BTW- if you do opt for light grease, just run a thin film into the ratchet ring, but do not get any behind the pawls. Grease behind the pawls is what glues them down delaying egagement.