Last couple of times I took out the Stinger I had a bit of slippage on the starboard side.
Initially I thought it was the hubs, so today I bought a pair of them and replaced them both. Unfortunately they did not need to be changed so I wasted 160 bucks for nothing as the originals were almost perfect?!?

I did a test in the bay after I replaced the new hubs and the starboard side still slipped a bit as the tach was bouncing all over and you could feel the boat not biting the water...If I kept the speed at a constant 3100-3300 it flew across the water ok - no slippage. It just had trouble getting on plane and when I punched it to 5100 it did slip again (only on the starboard side)

I think I will check the oil tomorrow in the res under the deck lid in the engine compartment. ( I will have to locate this!)
Does the transmission have anything to do with intermitant slippage? Maybe the oil level is low? Are there clutches inside and are they wet or dry type?
I understand TRS takes Ford type tranny fluid?

Am I starting to look int the right direction as I am not very familiar with TRS drives...yet!

Any comments or suggestions would be appreciated in regards to this intermittent slippage problem.

TRS can use solid hub props, Yes sounds like trannie issues. There are a few different ones it can be. A merc trans is the shortest or it could be a borg warner 71 or 72c. All are wet clutch. What ever trannie it is was likely damaged the first time it slipped. You can check fluid for a burnt smell. I would guess now the propeller spins slowly in neutral indicating the clutches have heated and warped or melted together.
Sorry slipping is never good. After a few seconds the damage is done. If the fluid was low and you filled immediately and it only slipped for a second and you backed off you might have saved it.
Maybe you will get lucky.

sounds like you are losing your tranny, been there done that.

Tranny, went through three before I had the Hubers built.

Are you sure it's not propeller cavitation?

What kind of props do you have?

Ratickle, I'm looking at increasing from 420 hp to about 500-550 this year in my 87 Formula 311. I just heard about Hubers today. How much did it cost to have them go through them and what did they do?