Does anyone know what type of oil goes in the diffs and the gearbox for the front driveshaft?

 

I don't have a 300 owner's manual, but I would bet it calls for an 80W Hypoid Gear Oil ("hypoid" is the important word here!). If you can't decide what to get, just get the Honda "Shaft Drive" oil and then you don't have to guess if it is right or not.

One other note. This model has a terrible "open" differential (send power to the wheel without traction!). It has clutches that can stick sometimes, and if you feel your steering getting weird, you may need to add some friction modifier to free up the sticking clutches.

 

There is a gearbox on the front of the engine for the front drive shaft it has a place to pour oil in but I cant figure out how much goes in

 

My buddy has one, I will try to remember to ask him. On the other hand, it won't take much. I presume it has a weep hole (?). Just fill it until it comes out the hole.....

Later on, Honda wisely turned the engine sideways and they run the driveshaft right out the back, so this silly setup where you have to do a 90 degree angle change, gets eliminated.

 

I'm interested in the answer for how much oil to put into the gearbox??? Anyone know? I don't own a manual for my 97 trx300fw yet..but will soon!

 

Never mind, i just bought a PDF of the owners manual....worth the $5 us:
There is an inspection screw on the front of the gearbox, take out the screw and fill until it drains out the whole. Its approx 1/3 the way up the gearbox. I don't know how to upload a pic....drop me a PM with an email address and I'll send it to you.

 

I think one (front?) has a screw to show full, and the other one has a fill cap on the side and the oil level goes up to the bottom of that.

Honda likely specifies 80W hypoid gear oil. A quality 75W90 would be fine, as long as it is rated GL5 (highest rating for hypoid use).

In a hypoid gear system, the teeth actually slide laterally as they mesh, and they require film strength from a quality oil.