• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Wandering Shift point problem.

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
ThunderTiger

ThunderTiger

Hardcore RCTalk User
Messages
1,545
Reaction score
6
Points
173
Location
London (U.K)
RC Driving Style
  1. Bashing
So, i get my revo running, shift point seems ok. Second run, no adjustments it fails to shift, so i set the clutch to engage into second sooner (by a 1/4 turn). OK, all seems fine and shifting exactly where i want it to shift. Pull it in and stop engine, go home. Next day, clutch shifts too soon, but leave it and play for 30 minutes. Have to go out so put it away. Get back, fire it up, and it refuses to shift, no matter how much the engine screams its little heart out. set it back to original point, wont shift, so Re-set it back to the 1/4 trun point i made before, STILL won't shift.

Now, i have stripped it out, cleaned it and made sure that no debris of any form is stopping the free movement of the clutch, nothing was, so put it back together.

Same thing happens. First it shifts, three maybe four times, then refuses to shift at all. I have even tried swapping out the second gear clutch for my spare, but same deal.

Engine is tuned fine, same rpm's are being hit every time but the tranny is shifting three or four times, then not at all.

Is it that the second gear clutch is just screwed up or am i not doing something i should be ?

can i and do i need to replace any of the second gear clutch components ?
 
first, are you oiling the hole where you adjust. second are you having tuning issues
 
No i am not "oiling" the whole where it adjusts (it sais "no oil" anyway) and i have no tuning issues either.
 
okay just trying to get the simple things out of the way. have you emailed traxxas this has to have happened before
 
Yes, i emailed traxxas, but they have no idea what it could be either, they recommended cleaning it, adjusting the shift point and if that did not work, buy a new second gear clutch system. Typical company response of if it works but you seem like you don't know what your doing, BUY A NEW PART FROM US !!!!!!! AARGHHHHHHH
 
I had this problem before.I went to LHS and bought a new clutch assembly and put it on.Now it works just fine.You might want to try that.
 
Thats the trouble, my LHS will not have anything to do with traxxas products. PERIOD, which just leaves me to buy it over the net and in the UK, i can't seem to find a decent company to get one from.
 
i know, i just sorted it. a brand new, complete tranny for £23 POSTED !!!!!

I also found a company, so i ordered close and wide ratio gear sets, a 17 tooth clutch bell
 
ajames942 said:
Are you tuning it? Too rich, it wont shift....
Click to expand...

In answer to that, i refer to this

Thunder_Tiger_EB4_S2_Pro said:
No i am not "oiling" the whole where it adjusts (it sais "no oil" anyway) and i have no tuning issues either.
Click to expand...

AND, further to that, it is perfectly tuned. Not too rich, not too lean.

Besides, i just bought a complete tranny, so i'm hoping that i should have solved the problem completely.
 
doughboy0001, Towerhobbies is a US company, i'm in the UK. I need the parts ASAP, not in 2 weeks.

I also just discovered a UK company and have ordered the necessary componants for a FOC on the new tranny. Since i will be fitting the new tranny as a whole unit, i no longer need to buy a separate "primary clutch" (second gear clutch).
 
Not sure what type of terrain you were working with, but when I was at home in my front yard tuning....I was in grass, and I made some passes down the street and my Revo was shifting PERFECTLY. I brought it to my first race and it was stuck in first gear the whole time down the front straight away....screaming like a banshee and causing the crowd to stare at it and wait for the carnage.

I brought it home...ran it again...shifted perfectly. Back to the track....same shifting problems. So I stood on the front straight and made a pass by my feet and could hear the wheels slipping and losing traction when I entered the straight away. So I tried another pass with less throttle and then slowly ramping it up....it shifted perfectly.

So I adjusted my shift point to shift earlier by a half turn or so, same problem. Went another half turn....shifted occasionally. One more half turn or so and it was now spot on for my track. So in my experience (albeit limited) if my Revo loses traction and starts some wheel spin on dirt when WFO, the tranny won't shift reliably. I adjusted it to shift earlier and now I can come into the front straight WFO slipping or not slipping and it will shift @ 50-60 feet down the straight in almost perfect timing.

Not sure if that info helps or not....but terrain had a HUGE impact on my Revo and it's shift point for some reason.
 
It won't shift when running on tarmac, it won't shift running on grass, yet it was tuned to shift on dewy morning grass. I even tried it on tarmac again, nothing doing. I tried tuning it to shift a lil later on tarmac, still nothing, so set it back to how i had had it and it still wouldn't shift.

Ahh well, maybe the new tranny will sort the issue out. Maybe i just have a bum clutch that needs replacing. Either way, i will know when i get the new transmission in.

suicide, doughboy0001, weezracen, Motogod thank you all for your help/advice. It is appreciated greatly.

Once i get the new transmission in, i will let you know what happens.
 
Definately keep us posted. I had issues today at the track with mine shifting sporadically again...but I had pretty heavy mud all over it ;-) So it weighed a good 10 lbs more than when I unloaded it. hehehe
 
OK, so it' been a while since i started this thread, but an update is required.

New tranny arrived, as did the "long leg" wide ratio tranny gears.

Even with the new tranny and a brand new primary clutch i'm still having shift issues. I've had the engine professionally-tuned (even though i am more than capable to do it myself) and fitted new clutch shoes (and spring) to boot.

I have tried running on tarmac, still wont shift even when adjustments are made.

So today I fitted a brand new primary clutch (2nd new primary clutch to date) still not shifting into second gear. Tried adjusting it for over two hours and still nothing doing

This thing is driving me nuts to a point that I am about to give up on it and sling the thing in the cupboard.

There is no clutch slip, the clutch shoes are brand new, the clutch bell is not glazed, the tuning is perfect with standard ratio cb & spur gear, it sits on standard rims and tyres. all CV joint grub screws are tight and there is no binding in the drivetrain. The Tranny has a FOC.

Running on 16% fuel.
 
I know what it is!! The one way bearing on your first gear (the bigger one) needs to be cleaned and re-oiled. Just a drop of thin oil only! Take a little fine steel wool to the shaft that it rides on too. It is slipping and causing your early shift. First gear relies on that one-way bearing to hold tight. As for the late shift, you have your 2-speed clutch too tight. Don't forget the teflon washer that goes behind the first gear.:thumbup:
 
Early shift ? late shift ? WHAT SHIFT !!!! This thing just will NOT shift and the tranny is BRAND NEW including the FOC that's fitted.

I followed the E/D's from traxxas to ensure all was ok and in the right place when fitting the FOC.

The tranny refuses point blank to shift even WITH the brand new primary clutch, hence my annoyance.
 

RC Builds

Back
Top