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new2rocks Guide to the TRX-4

Updated the spur/pinion mesh section based on further testing and monitoring forums/FB. The stock motor position (hole "C") leaves mesh too tight with the stock pinion (11T). Placing the motor in hole "D" with the stock pinion provides much better mesh. Based on bench testing other pinion sizes, the manual's recommended motor positions for other spur/pinion combos also appears to be off (too tight) by one hole, so recommendation is to use one hole further out that recommendation in the manual.

Also, pinion alignment with the spur gear appears to be off on many of the first production examples. Recommendation is to check alignment and adjust as needed before running the truck. "thumbsup"
 
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So is it true some people were getting transmissions with plastic gears in them? I went through mine today and its all metal except the shifting mechanism I hope they release an aluminum one.
 
So is it true some people were getting transmissions with plastic gears in them? I went through mine today and its all metal except the shifting mechanism I hope they release an aluminum one.

Yea some of the early models that Hobby Shops got, mine is one of those models.. no issues other than maybe its quieter 8) Just to clarify its just one of the gears that's plastic, 1st gear I think? The rest is like yours. On the plus side mine came with an OK amount of grease at least. It wasn't packed in there but it was there, including in the differentials. And I learned that the backwards facing diff cover screws are a pain to remove with any reasonable sized tool if you try and remove them without taking anything else off.
 
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I tried the D position and found it too loose. C with stock pinion is not wearing the spur abnormally and shows just a teeny tiny bit of play on both rigs I've looked at.
 
I tried the D position and found it too loose. C with stock pinion is not wearing the spur abnormally and shows just a teeny tiny bit of play on both rigs I've looked at.

I had the same experience. I tried the D position after reading so many warnings - not because anything felt or sounded strange. Felt too loose so I switched it back.
 
I tried the D position and found it too loose. C with stock pinion is not wearing the spur abnormally and shows just a teeny tiny bit of play on both rigs I've looked at.



I had the same experience. I tried the D position after reading so many warnings - not because anything felt or sounded strange. Felt too loose so I switched it back.



Thanks for chiming in...that's helpful to know. Sounds like either their tolerances may be a bit loose or there was a part update that addressed mesh once production started. I know mine were definitely too tight in the C position, and I tried several other pinion sizes with the manual's recommended motor position and found the same issue. Either way, I've updated the guide to account for some people (like me) having mesh too tight and others having it be just right in the stock C position. "thumbsup"
 
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Yea some of the early models that Hobby Shops got, mine is one of those models.. no issues other than maybe its quieter 8) Just to clarify its just one of the gears that's plastic, 1st gear I think? The rest is like yours. On the plus side mine came with an OK amount of grease at least. It wasn't packed in there but it was there, including in the differentials. And I learned that the backwards facing diff cover screws are a pain to remove with any reasonable sized tool if you try and remove them without taking anything else off.


I changed out my diff covers to the red ones and wanted to put some grease in there. There was barely any in there... (i bought mine from a local hobby shop first week of june...) I had to remove the lower shocks/links screw and pull the drive shafts so i could twist it enough to use a driver... kind of a silly thing, but surely noted. All in all, its better then a bomber to work on... hahahaha

Also, slot C motor mount was too tight on mine also... slot D was the fix for mine... once again, i got one of the first ones shipped.
 
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I just posted another installment of "Shut Up and Drive!" featuring a mostly stock TRX-4 (added the BowHouse RC Low CoG Battery Tray and a Holmes Hobbies SHV500 steering servo) going head-to-head with a mostly stock kit-built SCX10 II (stock except for BowHouse RC tranny flip kit and GCM Deep Dish wheels) through some challenging lines that test overall balance. Despite all of the differences between the trucks, it's amazing how similarly they perform.

Even the powertrains (stock TRX-4 550-can 21-turn motor and XL-5 ESC on 3S vs. Holmes Hobbies Puller Pro Stubby 3300 with Trailmaster BLE ESC on 3S) end up producing similar low-end grunt and top speed, though the TRX-4 needs a 2-speed tranny to do it. Go figure, lol...

Here's the video:
<iframe width="560" height="315" src="https://www.youtube.com/embed/FkBZuCqT-i0" frameborder="0" allowfullscreen></iframe>
https://youtu.be/FkBZuCqT-i0
 
This is good to know as I'm still waiting for my TRX-4. At least I have a few tech info here under my belt for awareness. Kudos all!

Sent from my SM-G930W8 using Tapatalk
Same here. New2rocks thread has givin' me some very valuble info on the rig as I wait for mine too. Can't wait for a comp this weekend in Richmond,Va with my Scx10ii in the meantime.
 
Nice video there! It looks like they did fairly well. Was there some gear crunching at the 5:05 mark at the end of the first drag race?
 
Nice video there! It looks like they did fairly well. Was there some gear crunching at the 5:05 mark at the end of the first drag race?

Lol...Roo was a bit abrupt letting off the throttle on the 10.2 the first few passes, and at that speed, a moderate drag brake setting will bring the proceedings to a halt very quickly. So there was definitely a bit of clickling going on. He got much better after a few passes and some coaching (lecturing?) from dad. Whatever damage may have been done will be moot soon enough, because I'm planning to replace all t-case and tranny gears in both of our 10.2s with hardened steel ones next week (waiting on parts) after one of the tranny gears in his 10.2 stripped a few weeks ago in other hands. "thumbsup"
 
I just tried out a set of 80mm shocks (Gmade RSDs), and what a difference! The truck is much more stable, and the stance looks much better.

DSC00391.jpg

DSC00431.jpg

So I've now updated the suspension section to make that a recommendation.
 
I just bought my trx4. I want to thank the author of this thread for making a guide so complete and interesting.
 
Are those RC4WD deep dish wheels with the hub reversed? Great guide. Wish I would have known about this sooner!
 
I just bought my trx4. I want to thank the author of this thread for making a guide so complete and interesting.

Glad you're finding it helpful! "thumbsup"

Are those RC4WD deep dish wheels with the hub reversed? Great guide. Wish I would have known about this sooner!

Thanks! Yes...those are RC4WD deep dish wheels inside out, and they work great. I had to do an ever so slight bit of trimming on the upper steering arm to avoid rubbing with the wide tires staying tucked. Before:
DSC00399.jpg

After:
DSC00400.jpg

With that and a washer to cover the 6mm portion of the stub, the fit is spot on. "thumbsup"
 
Glad you're finding it helpful! "thumbsup"



Thanks! Yes...those are RC4WD deep dish wheels inside out, and they work great. I had to do an ever so slight bit of trimming on the upper steering arm to avoid rubbing with the wide tires staying tucked.



With that and a washer to cover the 6mm portion of the stub, the fit is spot on. "thumbsup"

Ha! I did exactly the same thing with some black ones. I think they look cool. Then I got silly and bought some Gear Heads. I love spending my kids inheritance on a "toy truck",as they call it
:lmao:
 
5197b05cdde3b22d33c67390000b677b.jpg
. Repurposed nicely on Brand X new2


Sent from my iPhone using Tapatalk
 
A potential tip for the TRX-4 is a pack of 5 futaba servo extensions, wire them in then seal your radio box from water. Make sure you label them! It should make maintenance on the truck quicker and easier while maintaining the water resistance of your receiver box.

I currently have a pack of 100mm ones on the way to me.
 
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