tkhoo

Hi all, may I know that why my Yokomo GT4 2 speed tranny can't shift to 2nd gear even those I already loosen the set screw during I running at stright at high speed?
2nd question are, posisble or not my engine over heat if I run at long stright with high speed if my 2nd speed not shifting?? Temp. ~230-250 degree F.
Thanks in advance for your reply....................

spadworld

Ok here's my answer to your questions.
If the tranny is brand new the clutch may slip until it breaks in. I purchased a NTC3 and Argued this for a whole week NOW that my clutch for 2nd gear is broken in it grabs better and you definately hear the change. Look at the speed of it. is it still picking up speed as the RPM's stay the same? If so then your 2nd gear clutch is slipping and will soon break in. Run the car at about 1/4 - 1/2 throttle and listen to the car. This will make the engine definately change RPM's when it shifts. Also PUT your clutch BACK TO STOCK recomendations. and make sure the clutch spins freely when not running. The gears should spin easily one way and not at all the other.

If you have constant air flow over the head it shouldn't over heat. If you are chasing the car down the road you can since you will sustain the high RPMs over a longer period of time. 250* isn't that hot to the engine actually it's a little cool.
Hope this helps.

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tkhoo

Yes you are right, the tranny is new........... but I already use to run it at around 3 hours and try to loosen it but still can't shift. May I know that this 2 speed clutch need to broken in? May I know that which need to spin freely?? 2 speed tranny or the clutch the engage the shoe bell?? There have two set screw, one is to tighten ( center one ) to the shaft and the other are to adjust the shifting time. still not clear.....

I already check at web site regarding the 2 speed tranny for NTC3, but NTC3 2 speed tranny is same like Serpent Impulse one. as for yokomo GT4, is other type.........The drawing I can attach at here because it use PDF format. You also can find at www.yokomousa.com---> kits & RTR ---> GT4 RTR ---->
GT4 Series Manual



Yes, I have constant air flow which I cut down the front, rear and both side of the screen. May I know that 250* not consider hot?? But when I put water at the head the water boil away........

Please advice..............and thanks in advance.

khoo

spadworld

the water should boil away within 2-3 seconds. That's considered about right. If it jumps around then it's too hot.


As for that style clutch I have no idea on it but to set it at recomended settings and run the tar out of it until you start to notice it shifting then work from there. Mine took about 5-6 tanks to start to notice it and it's still breaking in.

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tkhoo

yes, the water jump at the heat sink........I think it cause by the 2 speed tranny not shifting at the long straight......and cause it over heating.
So thanks for you reply...........and hope other forumer can help me on this.