slight gear problem

[topforcein]

I gave the grand hauler a little run today after I finished it all seems OK apart from first gear. It sounds like it is selecting it but no drive. Second and third seem fine.

Any ideas what I've done wrong.

Plz remember this is my first truck and also 3 speed box build.

[Tamiyabigstuff]

Did you check the operation of the shift forks & shift rod before you put the gearbox casing on ?

I've had issues with one of these in the past - shift fork binding on the shift rod...

[Backlash]

Before you disassemble the truck, turn it all on and then carefully turn it upside down and visually check that the servo is pulling the shift rod all he way out, or to the front of the rig to fully engage first gear (The E ring on the shift rod at the rear of the gearbox should be touching the gearbox when in first gear).. It may just be that you have to adjust the length of the shift servo's arm, and the linkages (or your radios End Point Adjustments (EPA's)) to get it to fully engage first gear.. (I have had troubles here more than once)..

If the shift servo is set correctly, then you will need disassemble the gearbox and recheck the orientation of the shift forks, clutches and gears inside..

One word of advice though.. Before you refit the gearbox to your truck, connect the motor wires to a battery (either use the 7.2V pack, or even 2 D size Alkaline cells will do) and manually move the shift lever to first and third gear with the motor RUNNING, and make sure that your getting all 3 gears...

[topforcein]

OK so I finally got the chance to have a look today I started with turning the truck upside down and tryed the servos ajuster from the first notch to the fifth one on the fifth one it goes into first but it seems to slip in and out while the truck is in motion know as of yet I won't tryed adjusting the shift rod. But I took the gearbox out and removed the case and all seems fine their I also connected it back up before I reinstalled it and by moving the gears manually they all select fine and mess fine also. Know that's as far as I have got so far I haven't yet fitted the gearbox back into the truck so I would say I am back at square one until I try the shift rod.

[Backlash]

Topforcein,

What radio are you using with your truck??

I use a Turnigy 9x, and I find that its End Point Adjustments (EPA) to be very useful when setting the shift servos throw.. I just manually set the shift rod to be in second gear when the servo is centred, and then just set the maximum travel in First and Third gear using the radio's EPA's..

The radio's EPA's are also useful for setting the steering throw as well to ensure that you get equal steering lock when turning left and right..

[topforcein]

I use the the futaba 4yf sport 2.4ghz fhss jobie

Again my first 4ch controller. Managed to get a 2 pack if gates for it from eBay for only £10 del

[topforcein]

Finally managed to get the time on the problem and have sorted it out at long last .

Just one more thing to ajust and I think I just might make a trip to radshape next Saturday for the trailer plus a few other stuff also.