Rs4 not shifing into second

[Mikester311]

I just bought a used Hpi rs4 (first edition) a few days ago and the car ran great until a friend of mine launched it up a curb and now the 2 speed transmission doesn't seem to be shifing anymore. The person I bought it from put a hpi 2 speed trans on there, but didn't give me any instructions on it. I have run 2 tanks of gas through it and it winds out in 1st gear. (I think) or at least I never hear it shift like it did before. Can it hurt the engine if I run it while it's stuck in first gear and how do I fix it so it shifts again?

Thanks,
Mike

 

[M@xximillion]

Start here This will get you familiar with the tranny, tear it down and look for broken parts.

 

[Çh®i§tiªñ]

Check out the tranny and YES running it steady, wide open throttle, at the top of first gear, for sustained periods, will trash your mill. 1st gear tends to go higher in the RPM band than the top of 2nd gear. Depends how you have it set, but most are.

Watch your temps.

 

[Mikester311]

Is there anything I should check first before tearing the tranny apart? What would cause it work one minute and not work the next? (besides jumping a curb) :bling:

 

[M@xximillion]

One thing you could check is the set screw, refer to the link above. The sudden impact could have knocked it out of adjustment.

 

[Mikester311]

Ok, I tried adjusting the set screw. It was all the way tightened down and I loosened it 4 or 5 different times counterclockwise to try and make it shift sooner. It never did shift but now it's making some really wierd rattleing noises. I'm also afraid that if I loosen the screew too much that it will rattle loose and fall out. I looked at the whole transmission and didn't see anything that was visable broken or loose. Any more ideas??

 

[Akina'sMtx-2]

You want to adjust it little by little, try turning it 1/2 of a turn out till you get it. Apply loctite on the adjusting screw, it will vibrate out of it's place and catch the 2 speed housing which will cause the tranny to lock, the car will die or keep rolling while breaking or throttling.

 

[Mikester311]

ok, I am a dumba@@!! I just realized I was tightening and loosing the wrong set screw. I was messing with the one that holds the tranny on the shaft and not the one for adjusting the shifting point. I don't know why it took me this long to figure that out??
Well anyways, now that I know the right set screw to turn, how far do I turn it? I mean, how do I know what spot it's at now? Can I back it all the way out and start to turn it from there or should I screw it all the way in and back it out to adjust it. I know you are suppose to turn it 3 or 4 turns in 1/4 turn increments, but at what point do you start? Does that make sense?

I'm still pretty new to all this.

Thanks,
Mike

 

[mcvickj]

Did you look at the link the Max posted? It has a small section about adjusting the shift point.

No one can really tell you how to adjust when it shifts. It all depends on the track you are racing at. During the warmer months I race at 3 different places and I always have to make adjustments each time.

An easy way to make sure you are in the correct hole is the allen wrench will be at a slight angle.

 

[Mikester311]

mcvickj,
Yes, I did look at the pdf that Max posted. I guess what I'm trying to say is at what point do you start to adjust the set screw? For example, if I just built the transmission and just installed the set screw, how far do I have to tun it before I get to the 3 or 4 turn adjustment stage? I know it turns way more than 3 or 4 turns and I just don't want to turn it too far or too little and mess something up. I read somewhere else that on another vehicle that you turn the set screw all the way down until it stops then back it out 3 or 4 turns. I also read that it could mess up the spring if you tighten the screw too much.

 

[mcvickj]

I see. I have the installation instructions at home. I will take a look at them when I get home from work and post back.