Packing a gearbox

[Vrdetailing]

My mad bull hummer has been used for wet driving.. The gearbox under water quite often in large puddles..

I noticed it was sounding louder and stripped it down to find water had washed the grease away.

I have cleaned it up and decided to pack the gearbox full of grease......

Sounds nice and smooth now and a slight drag on the gearbox as expected...

Has anyone ever experienced issues with putting too much grease in the gearbox

[Percymon]

If the grease is light enough then you shouldn't have many issues, but motor load will obviously increase - gear accordingly to account for the extra resistance in the drivetrain.

[s howell]

I would go down the regular clean and regrease route instead of packing loads in in one go.

[Vrdetailing]

It's quite a light grease... Gp lithium from work... It has a 3000kv brushless and the load when you hit a puddle at full speed is a massive drag lol...

I suppose I may be being lazy packing it full (well packed anyway)... It gets a lot of abuse and has been a strong box so far ...

[speedy_w_beans]

Something to watch for -- if your Mad Bull gearbox is getting louder it may be due to small debris lodging in the gear teeth and wearing the teeth some. I drove my Mad Bull at the beach last year and didn't anticipate a wave washing in and flooding the whole car. I was able to save the electronics by quickly rinsing and air drying everything, but I noticed at the end of the trip the gears had more lash and made more noise than normal. Replacing the gear set and cleaning the gear box interior restored it to like-new condition with minimal lash and quiet running.

As for grease, just a light coat on the gear teeth themselves should be enough...

[Vrdetailing]

Some fine grit had got in the box and the aluminium pinion is wearing causing powder in the grease... Sounds lovely now after a clean out with wd40 and packing

[XV Pilot]

The DT01 gearbox pod used by the Mad Bull has a small gap between the gearbox halves, near the motor, that can let dirt in. The instructions don't mention it, however the Rising Fighter (which uses the same 'box) comes with a small supplementary instruction sheet telling you to grease-seal the gearbox halves in this area.

I would suggest doing this next time you clean and rebuild your 'box. I grease-sealed mine when I built it, and it is still running good as new over a year later.

[MadInventor]

If you don't want to pack the gearboxes with grease you could always go down the route of using RTV sealant to seal the gearbox casing, and just pack a wad of grease behind the axle bearings. I did this with my txt-1 axles at one point, packed the ends of the axle tubes with automotive UJ grease, the cleaned the metal gears off and put light oil in them instead of grease and sealed it all up. The axle grease stops the water getting in and the oil getting out, and the metal gears run lovely and smooth in the oil.

[shenlonco]

what I do with all my gearboxes I put a small thin film of grease on the gear box halves where they seal together so that when you screw them together there is a grease seam that helps stop debris and water from entering the gear box.

[WillyChang]

you can pack it much as it will hold but its not like an axle rollerbearing,

extra grease will just stay in the nooks & crannies and only what's left

coating on the gearteeth is causing the drag.

Dirt shouldn't be getting into gearbox anyways.

On HPI Savage we used to apply thick grease to the outside of gearbox!

To seal the case joins & also where it meets the chassis plate, keeps grit out.

Sounds like you need some waterproof radiogear... Traxxas has for some time,

many others coming into the game too from cheap to bigbrands.

RX, servo, ESC all available... i just haven't found any waterproof TX yet

On real 4WDs diligent owners always do a complete fluid drain & refill

of sump, gearbox & diffs after coming home from any water crossings.

Its not a cheap exercise... easily $500+ in just oils & filters alone.

[ReaperGN]

Grease is not grease. There is one for every situation. Try some marine grease or a quality polymer that is waterproof. Either will stick to the gears even in water.

[Vrdetailing]

Cheers for the info... I know there are loads of types of greases being an engineer. I used what I had to hand as its my underwater basher..

I have greased the seal to the gearbox case now.

The water also seamed to get in through the axle bearings.. Put grease up the axle... and even into the diff housing....

I will see how it goes....

As for waterproof electrics... The hobbyking waterproof ESC motor combo has been tested to the limit and never failed...

I put my orange reciever in a ballon to keep it dry.

[Percymon]

Water will also get in via the motor spindle bearings if you are scuba diving

[Vrdetailing]

The motor is waterproof so I hope it stays out of there... I definitely go diving it's fun

[Mokei Kagaku]

My granddad had a wooden motoryacht for many years and he used to say; "The definition of waterproof is that water gets in, but not out again."

I think he was right.

[Vrdetailing]

Seams ok on the test run lol

[sidewaysdave69]

Madinventor car UJ grease, love it the choice of someone with disposable gloves. that stuff is horrible to work with.