But you can easily build a race-capable vehicle off of a Traxxas platform-- so it's a legitimate question. I would choose the RPM over the GH, if only for the choice of a-arm mounts, and the fact that those mounts are plastic. The FLM cases I run are my favorite gearboxes of all, but I've still had to replace the arm mounts because the holes invariably oval-out over time. Plastic arm mounts last a whole lot longer.

I still have an RPM box on my bench waiting to be installed. It appears to be very well made.

in that case, the extra weight for the aluminum will do better for your LCG mid motor to help the rear wheels gain some much needed traction, ha!

Mm.. I didn't think of that, coming from a racing background I always have a mindset dedicated to goin as fast as possible. Although I don't race my rc's.. I built a small track just for the purpose of bring able to do laps!

They used to
I still have my SRT and TRX-3 that I raced in the mid 90ties

Morten

Just received my RPM gearbox. I put the stock gears in it and got it together. I don't know if it's just my imagination, but it feels a little smoother than stock just by turning it in my hands. It's nice that they don't have the hole in the bottom like the stock case. The only issue I see is that when you look at the bottom front of the case (where the hole is in the stock one), there is a gap large enough to see the differential. Not sure if this will be an issue , but I'm just going to put some tape over it like stock. Here are a few pics with the gears installed.

Looking good, the gap should go away once you get the arm mounts on and mounted to the chassis.

Mine did not have that gap when assembled. Mine felt a good bit smoother once assembled, but I did put all fresh bearings in when I built it, so I think that was more of a factor. I put a conventional layshaft in and am running a stock TRX slipper on mine, and it is easily the loudest gearbox I have-- so the plastic must be harder than the usual RPM stuff, because it does nothing whatsoever to dampen noise. I was running Monsterslash with the RPM box and Ultra Slashipede (equipped with an FLM case) side-by-side and the RPM seems about three times as loud.

But the box seems to be very, very well made. All of the screws line up perfectly, everything fits nice and tight. The FLM will always be my favorite, but-- once durability is suitably tested-- the RPM stands to become my most recommended.

The new RPM tranny worked great on hte first run at the track, but I noticed something when I got home. There was an excessive amount of grease coming out of the gearbox where the left axle shaft comes out of the differential. It's a black grease like I have in the diff, so I'm wondering if it's just the diff. My gears in the gearbox just have a small amout of white lithium on them. I'll open it up and see when I get a chance.

Just got mine assembled and installed--love it! An annoyance I ran into though is that the stock Traxxas VXL motor mount screws (part #3931) will not work with this aluminum mount plate. The phillips head screws from the brushed cars fit fine, but the flat head hex screws from the VXL cars have a lip between the head and shaft that prevents them from sitting flush. On plastic transmissions, this lip simply presses in, deforming the plastic, giving extra bite. Obviously, this can't happen with a metal mount plate.

RPM should note this in their product description since they intend for you to re-use your old hardware. "NEW MOTOR MOUNT SCREWS REQUIRED," or include new ones with the kit. Anyway... what's everybody using to mount their motors?

I use Lunsford Fat Boys, but if I run a large Spur, I have to use a Traxxas screw on the top one to clear the gear.