Transmission kit testing (without servo or motor)

[gfmucci]

I am building a Twin Hammers kit. I've completed the transmission and I am not sure I got everything right.

The shifter rod does not fully engage inward by hand pressure right away when the gears are turned by hand. It does finally engage only after some fiddling with turning the gears several revolutions.

Does the shifting require motor-generated speed before it engages easily to low or high gear?

What is your experience with testing the shifting function prior to installing a servo or motor?

I don't plan to disassemble the tranny to check things out until I install the motor and manually test the shifting at speed to confirm if something is amiss.

[coryshad]

Sounds to me like it's probably operating normally. The gears have to be moving to engage.

[gfmucci]

Originally Posted by coryshad

Sounds to me like it's probably operating normally. The gears have to be moving to engage.

The question I have is do they have to be moving at least several hundred RPM (as with a motor) as opposed to just turning the shaft by hand to test? I've turned the shaft by hand several revolutions expecting the gears to engage, but even after several revolutions they don't fall into place sometime. Well, I'm getting the motor at the end of this week, so I guess I'll find out soon enough.

[meatmonkey]

I noticed when I built mine that it did the same thing. I took the trans back apart, and polished up all the mating surfaces between the lower selector and corresponding gears. All to no avail. Later noticed some one mention polishing the shift shaft where it passes through the trans case, so I took it back apart and did that, and it seemed to help a little.

Really though, everything is so tight fitting that if it shifts at all in your hands by finger pressure, it will "work itself in" when a servo is running it while your shifting gears on the go.

[gfmucci]

Ahaa. That is what I was hoping...it all needs time to work itself in - nothing that a few hundred thousand RPM and a few dozen shifts won't cure. I was dreading taking it apart again. Those screws are awfully tight. I was even looking at replacement screws if I messed up the heads pulling them out.

[Lewis110]

I built my transmission this morning and the transmission feels extremely tight. I know there's a ton of gears in there and I used black grease. I'm thinking I should take it back apart to make sure everything is correct.

My question is are they all real tight feeling?

[gfmucci]

Originally Posted by Lewis110

I built my transmission this morning and the transmission feels extremely tight. I know there's a ton of gears in there and I used black grease. I'm thinking I should take it back apart to make sure everything is correct.

My question is are they all real tight feeling?

Good question. Based on both your and my experience, my guess is all the kit transmission case screws are very tight - I mean torque screwdriver 10 tight. That is why I didn't take it apart again to check it out because I would probably screw up more than I fixed. The tranny works fine as long as the transmitter settings are correct. That has been my biggest challenge. Sometimes it shifts fine - other times it takes a few seconds to click into gear.

[Lewis110]

I took it apart this morning and checked everything out. Its the way the manual says, so it must be good lol

I was having a problem with shifting also. It just would not shift into high gear. polished the shifter shaft up. Reamed out the slightly where it slides into. And still nothing, went back to the manual yet again. A word of advice, when building the kit. Don't just look at the photos lol I had the 6.5mm spacer installed like the photo shows. But that just locked it into low gear. I guess some times you gotta read the fine print.

The trans still does feel tight when turning it by hand. But is slightly better now. So I'm guessing it will only get better once I get running it.