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Tmaxx 1.5 Does The Hop

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S

srusinek

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I have a 1.5 Tmaxx that now does the hop after I tried to adjust the two speed. I just installed a traxxas setup on my OS .18cvrx which was the flywheel, clutch and a Robinson Racing 22 tooth clutchbell. I ran it today and it would not shift and it seemed to be in second gear. As soon as I tried to adjust the two speed with the second screw if your looking at it with the front on your right it just hops now. I noticed the set screw was kinda loose so i tightened that but it still just hops with no forward engagement. Can someone please point me in the right direction so I can get this running again? Also is there a baseline setting for the two speed to start from? My MGT 8.0 has a setting to start with but there seems to be no mentioning of that in the manual. Nothing else was adjusted(slipper clutch and engine) before I adjusted the tranny. I'm also running a Robinson Racing 72 tooth spur gear with their optional slipper system. Thanks for the help in advance, Steve.
 
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Sounds like you need to do the forward only conversion. That will eliminate the hopping or jerking effect from the reverse clutch. After that you will prob need to turn the two speed adjustment screw to the right to shift later.
 
I went from being stuck in second gear to the truck just not engaging. After I tried to adjust the two speed tranny is when it started to not engage. I also heard that if the set screw that holds the two speed onto the shaft comes loose that it can cause what's going on. I'm just going to pull the trans out and go from there. Does anyone know where the starting point is for the two speed adjustment? Would traxxas have that info. Thanks again, Steve
 
The 2.5 tranny shift point screw should be approx 6 1/2 turm out from snug.

If the set screw that anchors the 2 speed hub to the shaft is loose the truck will still have 1st gear, it just will not shift to 2nd.

Open it up and find the most likely stripped forward primary gear.
The FOC is highly recommended for a smoother operating and stronger transmission.
 
I won't have anytime soon to pull it apart and when I do I'll definitely consider the foc. If the gear is stripped, could it be from the power upgrade of the OS engine? I never really hammered it or beat it. I'm thinking of going all metal inside if the damage is that bad. Does anyone have the part numbers for Robinson racing metal conversion? Thanks for all the help,Steve.
 
That transmission equipped with reverse is just prone to stripping gears.
You will not need steel gears with just a .18 engine if you install the foc.
Many people run BB engine with that tranny with a FOC and have little trouble.
 
For what its worth I'm going to reset the two speed adjustment to the setting of 6 and 1/2 turns out and go from there. I figured I have nothing to lose.
 
If you want to open up the tranny and check everything you can get the exploded view from the traxxas website. The foc is cheap and very easy to install and make a world of difference. As for the two speed adjustment screw I don't think there is a base setting, I would screw it in about half as far in as it will go and adjust from there
 
I seen the foc part online for cheap on tower and I've adjusted the two speed every which way so I guess its time to dig in and roll up those sleeves. Instead of pulling apart my truck that I'm kinda thin on funds for this Sunday, I've got 7 other ones I can drive:D
 
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Ok Now What?

I had some time this evening to pull the tranny out of my tmaxx. After seperating the tranny, I found nothing out of place or anything broken for that matter. I even went so far as taking a flashlight with the assistance of my wife to check all the gears inside. I also made sure that the 2 speed bolt down screw was tight and on the groove on the shaft. So now i'm completely stumped on what to do next. I have not reinstalled the tranny back in the truck in case I overlooked something. Again thanks for all the help, Steve
 
The black tranny with reverse will not engage the output shaft by spinning the input or spur gear by hand.
The internal clutch system needs quite a few rpms to engage and you just can’t spin it fast enough by hand.
I use compressed air and blow it on the spur gear to test with the tranny out of the truck. You will be able hear and feel the gear change happen with compressed air if the shift change occurs.
 
This week I'm on vacation from my job with nothing planned but rc and rest and relaxtion. This week I'm going to take it to my lhs and see what they think. It's hard to diagnose a problem on here if you can't see it. I'm probably going to install the foc and replace the friction pegs to start with, then go from there.
 
For that money you could ebay a new forward only grey tranny and driveshaft set. I bought a new grey trans for 16 bucks on there.
 
I'm going to my lhs to try and fix my tranny. What should I be getting besides the foc and the new pegs? I'll try to fix this one before I buy a used one that might have the same problem because you never know. Thanks for all the help given,Steve
 
I brought my tranny to the hobby shop and the guy there who is very knowledgable, said everything looks good. So I bought the FOC yesturday and then installed it today. The tranny seems more responsive when you turn it by hand and I'll be running it sometime this week when I get the chance.
 
Not So Fast

After installing the tranny I noticed the tranny is more responsive when the spur gear is turned by hand. I took it out tonight and still it does not want to engage. Before I put it all back together with the FOC installed, I checked the clutch shoes and spring and they looked good. Nothing abnormal or anything like that. So where do I go from here? Is there someting that I've overlooked? I have the two speed at 6 and 1/2 turnes out. It was kinda dark due to helping a neighbor break in his new truck so I could not adjust the tranny. The only thing I have not replaced is the slpper pegs which I think will be next.
 

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