Transmission problems

[Blxer]

After putting in a different esc and motor, the granite was stuttering at throttle, and grinding badly, when on the ground. When I held it in the air and hit throttle, it seemed fine.

Found the problem!

That little so n so right there!
That's a bearing out of the idler gear. Luckily the only other damage I found was the washers inside the diff. I'm rebuilding the diff with new bearings and guts, along with 50,000wt. diff oil.

 

[Walter]

After putting in a different esc and motor, the granite was stuttering at throttle, and grinding badly, when on the ground. When I held it in the air and hit throttle, it seemed fine.

Found the problem!

View attachment 169

That little so n so right there!
That's a bearing out of the idler gear. Luckily the only other damage I found was the washers inside the diff. I'm rebuilding the diff with new bearings and guts, along with 50,000wt. diff oil.

I also get the stuttering sometimes. I figured it was the sensorless motor cogging. I don't have the grinding you describe but it's making me wonder if I should take apart my transmission just to be safe.

I'll be curious to see what you think of the 50,000wt oil in the diff. The default for the Granite is 3,000wt for the MEga and BLS and 10,000wt for the BLX. Why are you changing it so drastically?

 

[Blxer]

It creates almost zero fish tailing, both wheels turn almost at same time. So when I hit the throttle, it goes straight instead of in circles.

 

[Aflan]

Looks a bit like my diff a couple of weeks ago.......And yes, that's it...I couldn't find anymore parts...The rest was grinded...

 

[Darren Wes]

Looks a bit like my diff a couple of weeks ago.......And yes, that's it...I couldn't find anymore parts...The rest was grinded...

View attachment 180

Wow.... thats impressivly bad. Happy to see all ypur gear aflan and blxer are in tact tho...cant waot to go blx trans

 

[Aflan]

Wow.... thats impressivly bad. Happy to see all ypur gear aflan and blxer are in tact tho...cant waot to go blx trans

Uhuh...I also was impressively stupid and ignorant at the time... ...I thought the car could take a lot more than it could... ...Cost me a pretty penny to keep her rolling in the beginning...

Damn...I am beginning to sound like a really old guy...RC wise...But I just started 3 months ago...

 

[Darren Wes]

Uhuh...I also was impressively stupid and ignorant at the time... ...I thought the car could take a lot more than it could... ...Cost me a pretty penny to keep her rolling in the beginning...

Damn...I am beginning to sound like a really old guy...RC wise...But I just started 3 months ago...

Truth be told the gears being metal don't make much a difference unless we can beef up the diff... before i finish building mine i will take it to an rc guy.., see about some ways to make it stronger.
I jist started 6 months ago and i get reminded a lot that i know very little seing as people make some incredible rc parts from scratch which put my "just running" issues to shame (how am i gonna weld this wraith, how big of a rc winch to pull this snow plow, well customized carbon fiber w/ logo seemed natural when puttin these 2 yeti's together)
Spent a bunch on the hobby already...like maybe too much....plus got some gifted stuff too. But im having fun and eveything is getting stuff paid. Honestly i put in like 600 after batteries shell pain stuff tires lights stuff motors..gels glues tape
But yeah i got everything i need!
Ill put in how much i spent when i make a build page. Finally tho i am getting close to having my number 1 done: fast enough to conquer the 8th scale buggy track by my place. Keep going

 

[Blxer]

Looks a bit like my diff a couple of weeks ago.......And yes, that's it...I couldn't find anymore parts...The rest was grinded...

View attachment 180

@Aflan, when you rebuilt your diff, did you put grease back in or diff oil, and if oil, what wt. did you you use?
Thanks in advance...

 

[Aflan]

@Blixer, I put in diff oil from Medial Pro, 15000 cps...Slightly thicker than the stock oil...

Could you also use grease to lube a closed diff?...Sounds like you would, kind of, locked it up when you would do that?...

 

[TpPartsRcXtreme]

I went up..might be 10k or more..don't remeber ..but the fishtail just went history!..

 

[Aflan]

/me bows his head in respect for the fishtail...After al the abuse he has taken...He has finally find his rest...

 

[slothkigg]

I went up..might be 10k or more..don't remeber ..but the fishtail just went history!..

So heavier diff fluid helps keep er straight eh? I'm going to have to try that. I rebuilt my diff that blew with upgraded parts like 2 batteries into owning the truck but used 5000 because my hobby shop was sold out of heavier stuff. It definitely fishtails like crazy in the loose stuff!

 

[slothkigg]

Also speaking of rebuilding diff my truck is still able to drive Buuuut it's making a click click clicking noise while I drive it. Wondering if I chipped a gear tooth the other day showing off at the hobby shop test day? (Might have landed on throttle once or twice bringing the nose up to avoid a huge stack) Anyone else ever had this issue? Like I said though truck still drives like normal, crazy wheelies, tons of speed ect. Seems like there might be slightly more cog though from a stop which leads me to believe it's possibly skipping a tooth or two until it catches and takes off. What do you guys think?

 

[Unusual RC]

Larger numbers for cps silicon diff oil is thinner, more water like. Smaller numbers are thicker (grease like)

 

[slothkigg]

Wait wait so 5000 is thick??

 

[Unusual RC]

Yes!

Arrma 1/10 stock metal diff has 10,000 cps.
I use 7000 cps, which gives a bit more traction in corners on dirt.

But my own thought or theory about this is as follows: a thicker oil prevent the differential gears from spinning fast, which reduces the wear and peak loads.

I am not 100% sure this is correct, but I do notice a difference when driving both trucks.

Thinner oil gives a smaller turning circle, but less traction accelerating out of a corner or bend.
Thicker oil larger turning circle, and more traction accelerating out of a bend.
That is the rule of thumb.

But all you bashers out there: only interesting if you race on a track

 

[slothkigg]

Well gaaalllly ya learn something new every day! Thanks for The info!

 

[Darren Wes]

So i guess if i rebuild a full transmission and all the gears are still good and i replace the oil and greases but the truck still isnt gripping when i spin the wheels off the ground is it probably my bearings or diff fluid wt

 

[Unusual RC]

You are welcome!
When I have Time I will make some 101's about many subjects. I am already busy with a few, others I will copy from my posts on the factory Arrma forum.

@Darren Wes: can you explain a bit more what you mean?

 

[ajdragon]

Hi

Has anyone ever thought about upgrading the diff gear from a 4 gear planet to a 6 gear planet.