Differential Questions

[22-250Fan]

I checked my front and rear diffs today for the first time. HINT!!! If you buy a new rc, check the oil in the diffs before you run it. When I opened the front on my BRCC, it looked like at assembly, they smeared a blob of grease about the size of a dime in the housing. Nothing touching the gears at all. The rear didn't have anything in it. Is this usual or did I get "Lucky"? The ring gear on the rear doesn't look in the best of shape but it'll work. The front had a little grease on the ring gear and looks like new.

My question is should I put diff oil or grease back in it. I'm going to start with 10k weight grease or oil to start with.

 

[slick2500]

I checked my front and rear diffs today for the first time. HINT!!! If you buy a new rc, check the oil in the diffs before you run it. When I opened the front on my BRCC, it looked like at assembly, they smeared a blob of grease about the size of a dime in the housing. Nothing touching the gears at all. The rear didn't have anything in it. Is this usual or did I get "Lucky"? The ring gear on the rear doesn't look in the best of shape but it'll work. The front had a little grease on the ring gear and looks like new.

My question is should I put diff oil or grease back in it. I'm going to start with 10k weight grease or oil to start with.

I would run oil iirc 10k is stock. Now I want to check mine out just to make sure.

 

[Brandon]

With RTRs, always check all fluids, shocks included. I removed the grease out of mine and replaced with oil. Kraton and the MT 4x4. Went 50k / 200 k / 20 k front to back in the Kraton. Not too sure on the MT off hand.

 

[22-250Fan]

With RTRs, always check all fluids, shocks included. I removed the grease out of mine and replaced with oil. Kraton and the MT 4x4. Went 50k / 200 k / 20 k front to back in the Kraton. Not too sure on the MT off hand.

I didn't even think about the shocks. Will be checking them out in the morning before I drive the 100 mile round trip to the hobby shop. I was so concerned about checking all the bolts and nuts, I didn't even think about the oils.

 

[Primarrma]

That's a bit disappointing, but like you say nothing better than knowing for sure. If you do it yourself at least you know it is done right(hopefully anyway). I'm getting a new Kraton at the end of the week when stock arrives again in Aus, so I'll have to do these checks, better than a busted drive line.

 

[GMballistic]

I checked my front and rear diffs today for the first time. HINT!!! If you buy a new rc, check the oil in the diffs before you run it. When I opened the front on my BRCC, it looked like at assembly, they smeared a blob of grease about the size of a dime in the housing. Nothing touching the gears at all. The rear didn't have anything in it. Is this usual or did I get "Lucky"? The ring gear on the rear doesn't look in the best of shape but it'll work. The front had a little grease on the ring gear and looks like new.

My question is should I put diff oil or grease back in it. I'm going to start with 10k weight grease or oil to start with.

Have you actually opened up the diff though to look inside?

Grease on the ring gear but inside the casing it should be silicone oil.

You can see all the grease around the differential gears casing below on my Typhon before I removed it...

Inside the differential casing though it should be filled with silicone oil similar to this...

 

[22-250Fan]

GMballistic -

I didn't open that up. I just didn't see anything in the housing. I'll tear into it again and see what's going on in there. It looks like you have a different set up than I do but guessing the same general design. Thanks for the heads up.

Just pulled the diff out of the housing and there was a little bit of grease on it. What would be the best way to clean this up with. Brake cleaner, carb cleaner, starting fluid?

 

[Brandon]

Just wipe it off with a cloth towel and ensure you have all the dirt off it. MGB is correct when mentioning you will need to take the diff apart to check the oil. Just remove the screws and pull apart to check. There are videos and numerous responses on cleaning the cups out and reinstalling. Careful with the gasket when reinstalling the pieces. You willl be placing grease on the outside of the diff - think it’s called the sun gear- when installing back in the housing.

 

[DoNoHarm]

Sun gear, ring gear, hell, some call it the big gear. That's the one that gets the grease (as said above)

My senton 6s diffs came filled enough out of the factory so I wasn't too unhappy with it. My trucks have been sitting for a few weeks at this point because of some viruses I've picked up, so I guess it's an excuse to work on them. My revo's center diff should probably be checked on inside (well it shouldve been checked about 80 runs ago) and if the fluid isn't glitterglue, I'll split it and add to my senton's diffs to stiffen them up and also finally fill them to the top.

 

[22-250Fan]

I just got into the "guts" of the diff. It was full of oil. I have got to keep in mind that these are not full size real cars and some of the pieces work a little differently. The housing was dry so the gears had to be too. Not so much. LOL. Live and learn. One quick question, did the Arrma factory use inch drive impact guns on everybody's r/c or just mine? Wow, some of those little dudes were really tight.

 

[GMballistic]

One quick question, did the Arrma factory use inch drive impact guns on everybody's r/c or just mine? Wow, some of those little dudes were really tight.

They can be a little tight yes but the worst bit is all the red Loctite (thread lock) that they use, ...that might be why you find some worse than others.

I found it particularly bad removing my original pinion gear from the motor as well as some of the chassis screws. To do it without damaging things or worse rounding off a grub screw you need to apply heat which I did using my soldering iron.
Just bear that in mind in future if you need to remove any as it is a lot easier doing that then trying to drill out a rounded grub screw.

 

[Adamj804]

Just wipe it off with a cloth towel and ensure you have all the dirt off it. MGB is correct when mentioning you will need to take the diff apart to check the oil. Just remove the screws and pull apart to check. There are videos and numerous responses on cleaning the cups out and reinstalling. Careful with the gasket when reinstalling the pieces. You willl be placing grease on the outside of the diff - think it’s called the sun gear- when installing back in the housing.

What brand/kind of grease do you recommend for the outside of the diff?

 

[Brandon]

I use either bearing automotive or red grease. Bought at local automotive store.

 

[jondilly1974]

Any grease for high temp.

 

[Adamj804]

Any grease for high temp.

Thanks for your help. I’ve had mine four 6S vehicles for two years and have never touched the diffs. It’s time to try to maintenance them. Everyone seems to have a different opinion on diff fluid but what do you recommend for just every day off road driving? Front center and rear. I’m not trying to win any competitions just want to keep the car is running.

 

[Brandon]

I believe mine is 50/500/30 or 20. F/c/r. Works well for my application. Dirt/ grass / some street. Helps with the balloon on the front tires

 

[jondilly1974]

Thanks for your help. I’ve had mine four 6S vehicles for two years and have never touched the diffs. It’s time to try to maintenance them. Everyone seems to have a different opinion on diff fluid but what do you recommend for just every day off road driving? Front center and rear. I’m not trying to win any competitions just want to keep the car is running.

You can simply stick with the stock fluids if you want. It really is a personal preference. Stock is F10k/C100k/R10k. Most here like heavier in the front and center, F30K/C500K/R10K.