I bought a used ofna ultra pro and the front gearbox was damaged. I bought a new one and replaced it. The differential looks good, but the gearbox is empty. Should there be liquid in the gearbox or not?

In electrics and the little gear train design, I always kept the drivetrains oil-free.

Please let me know!

Thanks
David

No, but you need a dab of grease on there.

Grease is fine for starters.

As you get more into the hobby, you will learn that you can adjust your buggy's handling characteristics by filling the gearboxes with silicone fluid instead of grease. Fluid is available in different weights. A good starting point for an Ultra would be 7,000 weight in the front, 10,000 in the middle and 3,000 in the rear (7-10-3 for short).

PS. There are many articles online about using fluids instead of grease..... suggest you read some for more info.

He is not talking about inside the diffs , asking about the gearbox the diffs sit in .

Think we're talking about the differential housing not the actual differential.So a dab of grease on the outside of the diff (as Da Smak said)...and inside the diff use oils (as you say).

Put some grease on the Gears in side the diff. housing(gearbox)
and make sure you shim it right or it wont last long

You guys are great. Thanks for the reply. This is my first nitro car. (I have 8 electric and only got this because it was part of a LOT of vehicles which was hard to pass up).

What do you mean shim the diff correctly?

I'll put a little grease on the bevel gear diff gear and it is good to go then. Awesome.

Hopefully the engine is in good enough shape. I replaced the glow plug and opened the crankcase up to take a look, no rust and while pulling the starter seemed to hold good compression.

Thanks again!

With shimming the diff, its basically like setting up an electric car's pinion and spur gear to get the right gap, but to get the adjustment for the diffs there will be shims on the inside of the gearbox on the outdrives, theyare used on both sides to move the crown gear closer or further away from the pinion, hope this helps