What grease does Shimano use on the worm drive gear on baitcasters? 

They don't. They use oil. "Bantam Oil" is the specific oil they recommend

The worm drive gear (white nylon or whatever plastic) goes in ungreased.

I clean with a Qtip, then a small dab of Ardent butter on each end and the middle.

This sure looks like grease to me. On my Antares...

 

https://imgur.com/446ZWFw

The worm drive itself ACE II

 

https://japantackle.com/tools-and-others/grease-oil.html

They use grease to make it quieter, buttery smooth, and more waterproof. I prefer oil so it doesn't collect dirt.

29 minutes ago, garroyo130 said:

The worm drive itself ACE II

 

https://japantackle.com/tools-and-others/grease-oil.html

This works, thanks. 

90 weight gear oil or a thin grease like zpi soft

Grease on an exposed application like a level wind is not a good choice imo. It collects abrasive debris and tends to gum up. 

10 hours ago, FrankN209 said:

What grease does Shimano use on the worm drive gear on baitcasters? 

That is how they get shipped from the factory, one more reason why I take apart brand new reels.The Ace 2 you found is the same as their standard drag grease that you can get in 1 ounce tubs .(see picture) No need to get from Japan Tackle just call Shimano and order. In my opinion you would be better off keeping a needle nosed bottle with Bantam Oil with you so you can oil all your worm shafts while out fishing........

Here is a picture of a 20 Met with a greased up worm shaft that I received a couple of weeks ago.....

Most of us fish in water that contains grit of some kind.  It attaches itself to your line and you retrieve it into your reel where it slings off into your levelwind.  You want your levelwind lubricated but IMHO, not with grease that attracts grit.  I use bearing oil on mine, a drop on each end to get the  bearings and one in the middle.  Fewer problems and less wear.

For me it has been ReelX on my worm gears for the last 20 years.  No bearings on my worm gear Shimano reels and I really don't want any.

All my new shimano reel come with grease on worm gear. I’m not sure if it is in fact drag grease (it is lighter in color and super sticky).

If oil is better why shimano use grease in their reel? I’m not expert nor engineer just wonder if it really matter. To me worm gear on baitcaster is not precision mash gear like main gear. Just a track gear with ~1mm gap for worm dive to run along.

15 hours ago, Delaware Valley Tackle said:

It collects abrasive debris and tends to gum up. 

Yup. It essentially becomes lapping compound which is abrasive aggregate suspended or mixed with grease.

2 hours ago, OnthePotomac said:

For me it has been ReelX on my worm gears for the last 20 years

Reel X here too.

30 minutes ago, Bass_Fishing_Socal said:

All my new shimano reel come with grease on worm gear. I’m not sure if it is in fact drag grease (it is lighter in color and super sticky).

If oil is better why shimano use grease in their reel? I’m not expert nor engineer just wonder if it really matter. To me worm gear on baitcaster is not precision mash gear like main gear. Just a track gear with ~1mm gap for worm dive to run along.

They lube reels at the factory for sale to the masses 90% of which will never clean or oil the reel. I also think they use lots of grease to give the illusion and feel tighter tolerances and smoothness out of the box. Cost and ease of application is another concern I’m sure. If everything from the factory was the very best possible ‘this forum and certainly this thread wouldn’t exist. 

49 minutes ago, Delaware Valley Tackle said:

They lube reels at the factory for sale to the masses 90% of which will never clean or oil the reel. I also think they use lots of grease to give the illusion and feel tighter tolerances and smoothness out of the box. Cost and ease of application is another concern I’m sure. If everything from the factory was the very best possible ‘this forum and certainly this thread wouldn’t exist. 

So if reel get regular maintenance, clean and re grease . All the accumulated debris shouldn’t damage the gear. I wouldn’t say grease is the best, nor oil is better. Oil on the other hand trend to dry down after a few months.

 

My advice is to clean and lube with oil and add a drop occasionally for best of both worlds. Everyone is free of course to do as they wish. 

Most of the Shimano reels I've worked on come with Permalub grease on the worm shaft from the factory.  I've seen some with the Star Drag grease as well, but can't confirm it was a factory job.  Like most others here, I prefer to oil this, and Bantam oil works great for it.  I've tried many things, such as ATF, 3 in 1, TSI 321, Remoil, and pretty much anything slippery works fine.  It comes down to what attracts and holds less grime and is easier to clean. 

I use CLP Break-Free,  2 oz bottle comes with a tube to apply a drop wherever it's needed. Doesn't collect dust, dirt or small particulates in water and lubrication stays thin in all temperatures you can fish in.

Tom