8xl revo!! - RC-Monster Forums

t-maxxracer32 · **8xl revo!! -** 04.26.2007, 10:37 AM

hey guys i got the revo up and running using 12 cells the 8xl motor and a mm esc and it is pretty sweet! right now its locked in first because it wont stay in second not really sure why... (i have the e-maxx tranny) can anyone help me with this problem? the truck only hit 24.2 mph last night and i cannot wait to see it in 2nd gear!!! if anyone knows why might it do this lmk!!

problem- truck will stay in first fine but when i push that thing in it just acts like im doing nothing... will stay in neutral...

solution?...

thanks!

BrianG · 04.26.2007, 11:38 AM

The two "teeth" on the dog gear might have been shorn off, or just worn down from when you were popping in and out of gear.

I recommend taking the tranny apart and checking everything. Take some nice clear pictures and post them here so we can see the condition of the gears. It'll be much easier to help you that way...

Dafni · 04.26.2007, 11:49 AM

Could also be the press pin that holds the second gear on the input shaft.

I bet when you open the tranny it all becomes clear :)

zeropointbug · 04.26.2007, 02:58 PM

Yeah, is this a new transmission, or a broken in tranny? I would think it's either the dog gear selector, or the weak roll pin in the second gear on the input shaft.

Finnster · 04.26.2007, 03:01 PM

Could be the shift servo is not quite lined up as well. WhenI 1st got my Emaxx, it had a JR radio, and would not shift past neutral until I adj the set points and throw. Just have to investigate.

Glad you like it so far, wait until you get into 2nd, and even run on 14 cells or 4S lipos. :)

zeropointbug · 04.26.2007, 04:12 PM

Quote:

Originally Posted by Finnster

Could be the shift servo is not quite lined up as well. WhenI 1st got my Emaxx, it had a JR radio, and would not shift past neutral until I adj the set points and throw. Just have to investigate.

Glad you like it so far, wait until you get into 2nd, and even run on 14 cells or 4S lipos. :)

True, it could be that too, like maybe the rod is not pushing far enough, to give it enough pressure to pop it into 2nd gear?

t-maxxracer32 · 04.26.2007, 06:00 PM

not using a servo to switch gears. i do it manually then holdit back by a spring. i will take it apart soon and see whatsup!! and this is for my freind. he will probably use 12 cells for a while but i am going to be using
6s123 when i get mine!!

t-maxxracer32 · 04.26.2007, 06:40 PM

not sure really what im suupposed to be taking pics of or anything but here are just some pics of the tranny opened up... lol lmk what you want pics of and i will get them for you!

kinda in a hurry so i will get better pics later

thanks as usual!

t-maxxracer32 · 04.26.2007, 08:13 PM

ok so after looking over it for about 15 min i dont get it at all lol... its peice a total peice of shit and now i cant even get it to work in first (i am in a bad mood right now cause i cannot fix it)

anyways there are 2 metal pinion like things in the tranny. are they both supposed to have little allen screws holding them in place? because the second gear (or the one in the back) spins freely. i think that is what is causing the problem.

lmk if that might be it

thanks

BrianG · 10:45 AM

OK, I edited your pic to help explain the tranny. They are kinda fuzzy so it's hard to see details, but that's ok...

Possible problem 1:
Both first gear and second gear are supposed to move freely if the dog carrier is not up against them. When you shift, the shift fork moves the dog carrier back and forth against first gear or second gear. There are two dog teeth (hidden in your pic) on each side of the dog carrier that engage on the sides of first or second gear. When this happens, the previously free-floating gear moves. Check these teeth to make sure they are there.

Possible problem 2:
Make sure the shift fork will engage both gears when moving it back and forth. If doesn't slide fairly smoothly, the servo may not have enough power to overcome this.

Possible problem 3:
You don't have a picture of the top shaft and the metal gears, but check to make sure both of them are securely fastened to the shaft. If either will turn on the shaft, the pin broke.

Possible problem 4:
How are your idler gears? These are the two smaller ones between the top and bottom shafts. These tend to get stripped which is why people get the steel idlers.

t-maxxracer32 · 04.26.2007, 10:36 PM

ok so is there a way to eliminate first gear? i dont use a servo to swtich gears i willjust lockit in second. how can i lock it in 2nd?

when i have more time i will look at the problems and see if any of those are mine

t-maxxracer32 · 04.27.2007, 01:50 AM

if i buy that cnc chassis xbrace thing http://www.rc-monster.com/proddetail...GMX05-TR-AL-WS

will it fix theproblem? or what exactly does this do?

thanks

Finnster · 04.27.2007, 10:32 AM

Quote:

Originally Posted by t-maxxracer32

ok so after looking over it for about 15 min i dont get it at all lol... its peice a total peice of shit and now i cant even get it to work in first (i am in a bad mood right now cause i cannot fix it)

anyways there are 2 metal pinion like things in the tranny. are they both supposed to have little allen screws holding them in place? because the second gear (or the one in the back) spins freely. i think that is what is causing the problem.

lmk if that might be it

thanks

:010:

If I understand what you are saying, it sounds like the roll pin for the top gear ("2 metal pinion like things in the tranny") for 2nd gear broke. This is a common occurance. Zero(IIRC) has a thread just below on this problem and a few diff solns. Basically you need to put a new pin in place to lock the "pinion" onto the top gear shaft. Some use 2mm hex keys, some use drill bit shafts, etc. Its a simple fix.

You can lock the tranny in 2nd w/o having to spend any money. Just remove the 1st gear idler and shift fork, and lock the dog carrier to the 2nd gear dog gear. I used 3mm screws. BrianG has a thread in the Revo section IIRC that illustrates this. For a fancier fix, you can just get the Gmaxx single speed kit from Mike.

1st gear is a waste w/ BL, so its recc either way. In stock fashion, the dog carrier engages the dog gear and slams the driveline as it can spin nearly 180* before the 2 tabs engage. Its does this every time you shift, and everytime you go to from Forward to Brake/Rev and vice versa. This is biggest contributor to Emaxx trashing diffs problems IMO.

skellyo · 10:58 AM

Quote:

Originally Posted by t-maxxracer32

anyways there are 2 metal pinion like things in the tranny. are they both supposed to have little allen screws holding them in place? because the second gear (or the one in the back) spins freely. i think that is what is causing the problem.

Those are your top gears and both should be held onto the top shaft with a roll pin from the factory. If either of them spins freely, you broke the roll pin. The answer to this is either a drill bill shaft or a allen wrench shaft cut to length and put in where the roll pin went. You can search here a bit and find lots of info on how to do this.

Edit: Somehow I didn't scroll to the bottom of the thread and see that Finnster had already answered this. Oh well...

Serum · 04.27.2007, 10:59 AM

What whappenf when my dogf loft hif teethf?

Wfraf wfrarf warf?