High Lift Transmission Selection Probloms... Help Please

[Tessa Maloo]

Hey there im hoping someone in here maybe able to help me or offer some advice. Im in Australia and have asked both the hobby shop i purchased from and the tamiya importer of how to solve this problom but so far to no avail.

I built the Tamiya high lift Hilux as per the instructions supilied. At the point where i ma required to test the operation of the servo for the gear change of the transmission is where the probloms start.

when moving the selecter stick on the transmiter left or right to engage the servo and move the servo horn which moves the small rod with the ball connectors on it that attaches to the transmission via a ball joint type connection on teh slector shaft.

The positions that the manual shows to be the correct positions for selecting the 3 geasr do not correspond with the actual movment of the shaft.

IN the diaqgrqam that shows selecting top gear it shows the shaft selctor hard against the gearbox housing.

In this posituion on my truck its approximatlly 4mm away from the housing thus not allowing a clean engaging tof the gears. In all 3 positions this is alos out by roughly the same amount. It runs most of the time cleanly in 2nd gear however.

AS the selector with the ball joint attachment is held in position on the selector shaft by a C clip or E clip on either side this does not allow for a different placment on te shaft.

The importer for tamiya put me onto their service departmant which is Castle Hill Hobbies in NSW. SAfter speaking to them they had mentioned similar probloms previously alos. They suggested a longer servo horn. As this with the mounting of the shift rod between the servo and the selector rod would give a longer throw and there fore acheieve what the manual shows.

In the manual the factory servo horn suppleid with the kit shows the fixxing of the ball joint fore the servo horn in the middle. I moved the position to the tip end of the horn. Althogh this helped going into top gear, when going the other direction into low gear it stripped the rod and the ball joint conection from each other leaving the rod from the servo stil attached to the servo ok but at the other end was just the threaded rod and the ball joint connector attached to the ball joint on the selector shaft.

i hope this makes sense to someone without and diagrams but as the local shops cant help me im hoping someone in here can offer advive or solutions if they have had similar probloms.

Thanks,

Ben.

[skip665]

Not heard of an issue such as this - what servo are you using just out of interest?

I think from what you are saying that the threaded rod stripped its way out of the ball end once you fitted the longer servo horn?

[TA-Mark]

Are you sure you have everything in the right order? The shafts the right way around? The images of the shafts in the manual are 1:1 so you can lay the shaft over the image to ensure it's the right way around.

Did you glue the bearings into the 'J7' cam? Failure to do this will see them come out of the cam and prevent it from going into gear properly.

Mine changes gear correctly. I am using the recommended Futaba servos and 4VWD radio. I'm in the outer most hole of the 'G1' servo horn. Can you adjust the length of the shift rod to get the right position?

Only thing I can suggest is pull it down and follow the instructions closer. Check the positions of the selectors and the action of the gearbox before you attach the side panels.

I never use 2nd gear. It's the only one that is soft alloy and will wear quickest under load, so I don't load it up. (Tamiya seem to like to put atleast 1 in each chassis so it will wear fast so we need to buy parts sooner).

[Tessa Maloo]

Yes did Glue in bearings as you mentioned. The radio gear im using is Jr gear which i had in my Bruiser. It works fine shifting gears etc in this. The only difference is the Bruiser has jr servos, where the high lift i have a basic Hi Tec servo as i didnt want to strip the servos out of the bruiser so as it stays in running condition, although it isnt driven often. Yeah s i mentioned i followed the manula to the letter and compared the actal rods to the plqans. Yes also the rod did strip out of the connector when i moved the ball nut in the servo horn from the middle position to the end position.

[Blacque Jacque]

Do you have adjustable throws on the transmitter ?

If you have ATV (adjustable travel volume) or EPA (end point adjustment), check the settings on them.

How far does the servo move with the shift rod disconnected ?

Try to set a ruler near the servo horn & measure the travel.

You need about 5mm in each direction to move the shift rod correctly.

[Tessa Maloo]

Thanks for the help so far. Im not out of the woods yet but have had some mixed sucsess tonight. Have managed playing around with different sevrvo horns and positioning of the horns on the servo in getting the correct opperation of the gear selector compared to the manual however im stil in need of some more advice if thats ok. I got low and mid working corectly but no hi and in driving truck on floor 2 spds were gained but the top wouldnt mesh but in driving i had torque going through wheels to get over a shoe or my foot. Later i got positions of all 3 gears operating as in manual but on putting on floor althogh i have 3 differnt spds that do mesh i have no torque as such in wheels. I asume may have something to do with sliper clutch. I mean if i put a shoe or my foot in front of truck the motor spins freely as revs increase but there is no drive as such over foot or show but when i move obstacle truck moves again. When truck held on my lap all seems good. This is in comparisson to when i had only 2 speeds opperating and i had torque at the wheels. Any suggestiuons? ay no stage have i changed setting on slipper clutch other than what suggested in manual. Thanks, Ben.

[Tessa Maloo]

Hey guys, thanks for the help. Im stil not out of the woods. Have played around with positioning the servo horn in slightly differnt positions on the servo and either get as i mentioned 2 spds with torque to wheels or 3 spd that work perfect on my lap but fail to offer any torque to wheels when on floor right way up. will keep persisting and if i find a solution ill let you know. Idf anyone has any other idears im welcome to hear them. I do also have more than 5mm movement in the servos. Alos is there any way to cheat and adjust the slipper clutch with out pulling the gearbox assembly out of the chassis?

Thanks Ben.

[TA-Mark]

Put the gearbox in 1st gear, lock the output shaft at the rear of the gearbox with a hex key through the universal or similar, then adjust the slipper nut which sticks out the front of the gearbox. I bonded the slipper pads to the spur gear.

Can you change the gears correctly without a servo by using your fingers?

[Tessa Maloo]

Will try what u mentioned about adjusting the clutch. Thanks for that. Yes i can adjust gears correctly using finger to move the selector and get good drive in each gear. Mind you have only done on my lap, not on floor with truck running.

[Tessa Maloo]

Adjusted the clutch as u described and got some btter sucsess. Got drive in all 4 gears and had torque to wheels. However it still isnt engaging gears cleannly eavery time and on occasion clutch sometimes seems to still slip. Is there any way or thing that could cause the clutch to slip or maybe i havnt assembeed correctly in some manner im unaware of?

[Tessa Maloo]

Hey there thankyou to to all those who offered me help and advice. its always hard to diagnose probloms over the net when you cant see whats happening and only going off a descrition.

On thursday night i was able to catch up with one of the guys at Barclays hobbies that has owned, built and run his own high lift. This proved usefull as could show him the problom.

Was partially my fault and in experiance and a missing part.

The radio gear im using was out of my bruiser and is about 20 plus years old. Stil works fine however the transmitter has no limits or end point settings (hope that right terminology).

As a result the shift of the transmission was moving the servo horn a lil bit further on each change than was required.

The second part of the problom was i was running a high tech servo Barclays had sold me for the shift servo, however the salesman that originally sold me didnt know there was an adaptor to sit on the servo to suit tamiya servo horns in the kit. I had been using a Acoms / Sanwa servo horn which on the hi tech servo was a good tight fit. However i didnt know it wasnt an exact fit and as a result when my transmitter was moving the servo horn further than it was required it was maybe slipping one notch on the servo. After a couple times it was actually moving fractionly from where it was susspossed to be and when was shifting the horn to far this was causing the shift rod to pull out of the ball connector on the servo or the the shift mechanism.

To compinsate for the increased movment in the transmiiter we moved the ball connector in the servo horn one hole closer to the servo thus making the horn move less than the manual states .

These things combined i did not know to look for and it has given me a sigh of releif of not having to strip the gear box down and start again.

I tried this out tonight and it seems to be working fine now. Hopefully touchwood it continues to do so and i can get on with getting the body painted and starting to modify the chassis as i learn more.

I hope this info is valuable to someone else in here if they ever experiance simmilar probloms.