Bought a used traxxas revo, have a couple of questions about identifying upgrades, and about a couple of issues

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SLiCKWiDNiCK

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23
Hello, so I have a traxxas revo, and I noticed once I got the engine un-dry seized and running, that the trucks transmission was randomly shifting into reverse. Well actually at first when I was giving it gas, it would just rev up and not move, then slightly clunk and go into reverse. So I took a look at the truck up close and noticed the spring for shifting was not connected to the shifting shaft (Lever?) Now, I had thought, for some reason, until a few hours ago, that sliding the throttle forward was how to shift from forward into reverse, but my local RC shop guy corrected me. I went home, and put the spring on the shift actuator, but the server is having difficulty moving the shift actuator to the end of travel for reverse and forward, at the servo connection point, I have to push it for it to end up at the end of travel, and if I don't push it, it just sits there buzzing and clicking. Could anyone help me understand how to fix this issue please?
I attempted the process outlined in the user manual for programming the optidrive system as I had played with the throttle trim without knowing it would have to be reset after messing with trim, but the shifting servo still does the same thing.. thanks in advance!
 

cbaker65

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Hello, so I have a traxxas revo, and I noticed once I got the engine un-dry seized and running, that the trucks transmission was randomly shifting into reverse. Well actually at first when I was giving it gas, it would just rev up and not move, then slightly clunk and go into reverse. So I took a look at the truck up close and noticed the spring for shifting was not connected to the shifting shaft (Lever?) Now, I had thought, for some reason, until a few hours ago, that sliding the throttle forward was how to shift from forward into reverse, but my local RC shop guy corrected me. I went home, and put the spring on the shift actuator, but the server is having difficulty moving the shift actuator to the end of travel for reverse and forward, at the servo connection point, I have to push it for it to end up at the end of travel, and if I don't push it, it just sits there buzzing and clicking. Could anyone help me understand how to fix this issue please?
I attempted the process outlined in the user manual for programming the optidrive system as I had played with the throttle trim without knowing it would have to be reset after messing with trim, but the shifting servo still does the same thing.. thanks in advance!
It could be a faulty servo ,maybe a stripped gear inside of it!

I am not familure with the Revo trans. but if the throw isn't right ,an it wont engage ,as most trans has a shift fork
inside them to move gears ,some times ,the trans. will even stay in a neutral position!

You can check if the linkage is adjusted right ,that's what I would check ,some linkages will vibrate out of adjustment or
a collar if it has one .will back off!
 

D3MON

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it almost sounds like either that servo is at fault, or the there is some mechanical binding. when you manually push the linkage to the desired location, is it hard to do or does it slide in pretty easy?
you are still getting buzzing and clicking from the servo means its trying to actuate but either has a mechanical failure internally or it is not powerfull enough to move what is needed (i.e. there is something blocking it from moving.
i know on many other models like the traxxas T-Maxx, AE Monster GT, and Losi LST, the reverse is a weaker point. i have not had experience with a revo though, but converting to with a Forward Only Conversion (FOC) would lighten the drivetrain reducing stress and wear, and also removing extra parts that may fail. down side to this is there is no longer reverse. (some like reverse, some dont care)
it would be a part that you would have to buy to do this though.
when you manually push the shifter linkage to the correct location, does the vehicle move forward as it should? or are you still getting issues with movement?
 

SLiCKWiDNiCK

RCNT Rookie
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23
It's pretty easy to push it into the proper position. But it sometimes can sorta easily get knocked out of position and will jitter a bit when that happens. Am I able to upload video here? It told me that mp4 is not an allowed extension..
 

D3MON

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It's pretty easy to push it into the proper position. But it sometimes can sorta easily get knocked out of position and will jitter a bit when that happens. Am I able to upload video here? It told me that mp4 is not an allowed extension..
Upload to youtube then post a link, or you can go to streamable.com and upload and post a link here.
 

cbaker65

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It's pretty easy to push it into the proper position. But it sometimes can sorta easily get knocked out of position and will jitter a bit when that happens. Am I able to upload video here? It told me that mp4 is not an allowed extension..
What is the current radio set up for that ,is it the 2.4? Also .what does the other servo's do?
 

olds97_lss

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The shifting servo on that thing was a micro server with plastic teeth. It's constantly under strain the entire time the truck is on regardless what gear it's in due to the spring. I can't imagine many last very long. Most people ditch reverse and install a FOC kit. That removes a handful of junk from the transmission to help it be more responsive due to less stuff spinning and you can also remove reverse servo and the optidrive. Simplifies things a bit.
 

SLiCKWiDNiCK

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The shifting servo on that thing was a micro server with plastic teeth. It's constantly under strain the entire time the truck is on regardless what gear it's in due to the spring. I can't imagine many last very long. Most people ditch reverse and install a FOC kit. That removes a handful of junk from the transmission to help it be more responsive due to less stuff spinning and you can also remove reverse servo and the optidrive. Simplifies things a bit.
Yeah I was looking at probably getting the forward only kit. Seems to have more benefits than having to have reverse..
 

D3MON

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definitely seems like that servo is having a hard time lol, i recommend an FOC, always had issues with reverse when i did have it so not having it didnt bother me much, and so much simpler to work on. getting the linkages internally sorted always gave me issues upon assembly.
either way hope you get it figured soon to be able to enjoy the truck! for now might be able to just zip tie the linkage to forward only?
 

SLiCKWiDNiCK

RCNT Rookie
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definitely seems like that servo is having a hard time lol, i recommend an FOC, always had issues with reverse when i did have it so not having it didnt bother me much, and so much simpler to work on. getting the linkages internally sorted always gave me issues upon assembly.
either way hope you get it figured soon to be able to enjoy the truck! for now might be able to just zip tie the linkage to forward only?
That's a great idea, I'll probably end up doing that till I pickup an FOC
 

Peeeenuuutt

RCNT Champion
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The shifting servo on that thing was a micro server with plastic teeth. It's constantly under strain the entire time the truck is on regardless what gear it's in due to the spring. I can't imagine many last very long. Most people ditch reverse and install a FOC kit. That removes a handful of junk from the transmission to help it be more responsive due to less stuff spinning and you can also remove reverse servo and the optidrive. Simplifies things a bit.
+1... reverse sounds like a good thing on paper but it really just causes problems.
 

cbaker65

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LOL......Shame on you Traxxas!

I would definitely get rid of reverse!

For the time being ,you can always pull the servo ,an wire the lever & lock it in forward until you
locate a FOC kit!
 

D3MON

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ohh wonder if you were seeing the full trans or the Robinson racing ones, Robinson is nice but don't know if that would be necessary as of yet lol
 

SLiCKWiDNiCK

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Is that a plastic set or steel? Because I found many plastic ones for cheap, but I figure if I'm gonna get a set, might as well make it steel as it will be less prone to damage. I found one place for steel at $40 per kit, but its payment portal wouldnt accept my visa debit card for payment..
 

SLiCKWiDNiCK

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Is that a plastic set or steel? Because I found many plastic ones for cheap, but I figure if I'm gonna get a set, might as well make it steel as it will be less prone to damage. I found one place for steel at $40 per kit, but its payment portal wouldnt accept my visa debit card for payment..
 

D3MON

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ahh makes sense, yeah that one was plastic geared, what engine are you running/plan to run?
 

olds97_lss

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If your sticking with the 2.5 or 3.3 engine, the plastic one will be fine. I only had issues when I went with a big block and the OS21TM engines. Then I went with the full robinson racing steel gears with their FOC. I don't think they offer a reverse option anyway.

My big block revo is a bit of a bastard, but on 21TM revo has the standard ratio RRP kit in it:
https://www.amainhobbies.com/robinson-racing-steel-forward-only-gear-kit-standard-ratio-3.3-only-rrp8002/p57427

My BB started life as a 2.5R slayer which has a different set of final output gears in it than the revo's do. At the time, I just upgraded the top shaft and 2 speed gears, then never had to deal with it again, even with an LRP28 in it. Probably 3-4 gallons ago, 5+ years.

Years later when I got another revo, I wanted to like the 3.3, but it just wasn't enough power for me, so instead of going full big block again, I spent $250 on the 21TM. It was ok until about the 9th tank of break-in, then I started chewing up the trans gears. After the 3rd time of pulling the trans out, I went with the full RRP kit in it and haven't had the trans open since. That was a couple years ago at least.

I don't drive my nitro's much anymore. But the $ I have in them, it's not worth selling either as your lucky to get 40% of what you have in them.
 
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