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Reverse Shift problems

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L

lozze

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Dear All,
this is my first post in this forum, and...
I have a Traxxas Revo 2.5, and I'm having problems with the reverse shift: the truck simply doesn't go backwards! Sometimes, I press the reverse button on the transmitter, and not even the servo moves...but many times, I can see the servo moving and switching to reverse gear, then I increase the throttle and the truck does 1-2 cm backwards, then stops, and I can clearly hear that the engine is spinning, but it loses traction...
I don't really know what could it be, if the Optidrive, or...boh...
Do you have any idea?
Thanks!
Yours
Lorenzo
 
The idle might be set too high. I've heard bad stuff about the optidrive. Doing a foward only conversion makes for a much smoother transfer of power and a lot tougher tranny.
 
if it was me i would open up the tranny and check the gears make sure no teeth missing or broken. sounds like it could be stripped gears. as far as the servo not working i would replace it with a new one.good luck i hope you get your problem fixed
 
I have 2 that do the same thing, no slipping though... The opti drive sucks. It takes a good 3-5 seconds to shift on my revos.
Does sound like your reverse gear is shot thought. If it shifts and doesn't move then the gears messed up. I think i'm going with everyones advice and doing the forward only switch.
They say you can take out the opti drive and still use reverse but you run the risk of wrecking your trany if you switch while driving..

I like repeating things that others say- It makes me sound like I know something...;)
 
Take the Tranny out and inspect the REAR of the BLACK gear that sits on the middle shaft (not the input shaft and not the output shaft) AT THE FRONT end of the tranny, check the face and teeth of the gear aswell. if there are any teeth missing on this black gear, it can cause locking of the rest of the transmission as the broken teeth get thrown around inside. this can also cause serious damage to the transmission gears, even causing complete siezing of the drive and possibly snapping the middle shaft (lay shaft / 1st 7 wnd gear shaft)). i know from experience about this and it cost me £40 to fix (foc kit, new gear 1st / 2nd gear set & new lay shaft). also check your bearings are running smoothly and that the action of the reverse fork is ok and the reverse linkage is correctly adjusted.

Removing the opti-drive unit; the opti drive can cause problems, but the removal of this places you squarely in the realms of possibly destroying your transmission if you are not at a dead stop. the best option would be to fit a forwards only coversion kit (FOC Kit), making the transmission lighter in relation to rotational mass. However if you intend to keep reverse and remove the opti drive unit, ensure you are at a standstill before engaging reverse.
 
Last edited:
Thanks to you all!
I unmounted the tranny and I verified that the reverse gear has not too many teeth left!!
So...I'm going to change it...
Do you know if there are instructions wiht pictures about how to unmount and how to re-mount a revo tranny?
Thanks!
Yours
Lorenzo
 
when i need pictures i got to traxxas website and use their exploded views. they are great. imo. hope this helps.
 
Thanks!
And...any of you knows if a Revo 3.3 forward only gearbox would be compatible with revo 2.5?
Thanks!
Yours
Lorenzo
 
REVO 3.3 and 2.5 Transmissions are the same !! i just bought and fitted a 3.3 transmission in place of my 2.5 one after i trashed it
 

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