Nitro Fumes

The idler gear from the P/N set A2927 keeps stripping. My original gear last about 2 full seasons. Then it stripped. So I replaced it. The next time I ran it the new gear stripped before I finished a full tank of fuel. Maybe 3/4 tank. So I thought maybe it was defective. So I put in another one. This time I got about 5 tanks of fuel through it before it stripped. I didn't even make it to the first heat race. It stripped during morning practice. Because this is rediculous having this gear constantly stripping out. The stock input gear (P/N A9931 is alum. I replaced the differential gear (P/N A2925) with the Robinson Racing alum gear when I first built it. Only the idler is Nylon and it keeps stripping now. So does anyone make an aftermarket idler gear out of metal?

All The Way

Check the case where the bearings go for the compound gear, I’ve broken several there and the end result is the compound gear destroying and taking the monster gear with it. Also make sure there are no plastic remains left in the top gear, some times they get jammed in.

MCSRacing

My Feedback: (2)

Exactly!

Nitro Fumes

When I rebuit it I cleaned all the teeth from the alum. gears, put it all back together and it all worked nice an smoothly. It all fit together quite well. It spun nice and free. But the idler gear is just too week a material. Perhaps they are using an inferior grade of nylon now.

All The Way

image is kinda dark but you need to check this area, if its cracked it will allow the compound gear to move

Nitro Fumes

I guess I should have added, its a new transmission case too so it's not cracked. I replaced the case the first time I rebuild it.

All The Way

hmm, bearings to?
I'm hard on my trucks when I race. If I find a spot I can land on power 9 times out of 10 I will, I'm never light on the trigger and I may have 2 in a year fail.
Not sure on this one, metal gears is definitely not a solution to a possibly bigger problem.

MCSRacing

My Feedback: (2)

i just replaced the cases in my drake, broke them at the output bearing carriers lol ...... i run the rrp aluminum diff gear and the delrin compund gear, ya must have a weak link to fail if something goes wrong .... the aluminum compound gears dont seem to last and better and they definately destroy ur trans when they go out

Nitro Fumes

I found out the problem finally. I was pretty disgusted so I didn't work on it for a while. The recess that supports the differential bearing on the left side was out of round so the bearing was loose. It was dropping the diff. away from the idler a little bit and not making full tooth contact so the the teeth stripped away. But I don't know how the transmission case got that way. It was a new case that I used when I rebuilt the transmission last Dec.. I replaced the case, the idler and the input gear/shaft during that rebuild. So I fixed it last week and had a race this past Sat. and it worked great. I mean the whole truck was great, the engine and the chassis was in tune as it hooked up really well too.