RC4wd aluminum transmission problem.

[the Mad Modder]

When RC4wd dropped the price of their alum transmission case from $90 to $50 I bought one because of the "cool" factor. I don't have anywhere to do serious crawling, so I doubt I'll notice any difference.
While I had the trans out I got my brother to make up a set of steel gears for me on his lathe following this thread.
http://www.rccrawler.com/forum/showthread.php?t=237764
I used Hot Bodies 5mm mod1 pinions for the top and middle gear and a machined down gear from the company ThunderVP mentioned for the bottom gear. Since it had to be machined anyway, it was recessed a little further and the stock 10x15mm bearing were replaced with beefier 6x15mm ones.

That's when the problem showed up. In the new alum case, the top two steel gears were binding badly. Strangely though, in the original plastic case they meshed perfectly. The stock plastic gears also were meshing too tightly in the alum case, to a much less extent, though, than the steel ones.
When I measured the distance between the top and middle gear shafts, the rc4wd case had the shafts positioned .006" closer together than the stock case.

I just wanted to post this, so you guys know this problem with the case. I had to use a 14t gear on the top shaft(instead of the 15t) to solve this problem. The 14t doesn't mesh perfectly, but it's a pretty good mesh that won't be a problem.

Pics of my setup.

Machined bottom gear with oversized 6x15mm Serpent bearings.

 

[vigilant]

ive never had any luck with anything from rc4wd besides their tires and shocks everything i have gotten was a lil off

 

[stolps]

It may not work quite right but I sure does look pretty!"thumbsup"

 

[the Mad Modder]

Unfortunately, the gear mesh problem wasn't the only thing wrong with their alum trans cases. Putting everything back together, I found another flaw. On the stock gear case, there's a recess in it to give the gear cover room to hook on to the bottom of the motor plate. The rc4wd one didn't have that recess, making it impossible(in current form) to attach the gear cover properly.
Fortunately for me I have access to my brother's machining equipment and I milled a recess into the case.

The stock case and my alum case after I machined the recess.

Also, they did not include any replacement screws; the stock screws are tapping screws and fine threaded ones are needed for the case.

 

[the Mad Modder]

ive never had any luck with anything from rc4wd besides their tires and shocks everything i have gotten was a lil off

This is actually the first time I've been disappointed in any of their products. I have bought a few things in the past from them and was very happy with their fit and quality.

It may not work quite right but I sure does look pretty!"thumbsup"

Hahaha, that's true.

 

[alibby]

That's a bummer, I was thinking of getting one of these cases...I already have the RC4WD Steel gears and I was thinking this would take out the play the plastic case has and lengthen the life of bearings and gears...I wonder if the teeth on those MOD1 Pinion's is larger then normal....I will ask RC4WD to look at this thread and comment before I buy the $50 case.

 

[northerngames]

mine should be in today or tommorow how much would you charge to add the recess to mine if possible?

 

[the Mad Modder]

mine should be in today or tommorow how much would you charge to add the recess to mine if possible?

Sure it's possible. Details PMed.

 

[northerngames]

Turns out I am still good I got the case in today.

I got the integy purple gear cover off ebay and it also comes with a motorplate/heatsink that is not mentioned and their both flush bottomed so no need for me to have the recess now becuase they go together like it was made to be but thanks anyhow.