problems with my mad rat
 

hi guys sorry to bother you all again, after the meeting today i stayed for a much needed practice,

after 10 mins or so the car just lost power to the wheels, i have had a look in the diff and it seems ok in there, no missing balls or flat bits and the gear has not broken either, built it all back up and seemed fine whilst holding it, then when i put it on the floor lots or motor noise and not much movement

i am stumped :mad:

any ideas?

cheers

Look if your motor is putt nice with the slipper and look if slipper is Ok

they are both fine buddy

[QUOTE=billyboy9002;485197

the car just lost power to the wheels[/QUOTE]

What do you exactly mean ? the motor turns high and freely but the wheels don´t turn? Is there a noise somwhere ? If EVERYTHING is fine, I will try like this: - other battery
- other motor
- other esc

the motor turns freely, and spins the spur, the wheels turn quickly whilst holding it but on the floor its like there is not enough torque/power to move the car

have tried a new battery still nothing

As you say you have lots of motor noise but not much movement have you checked that the motor bolts have not come loose so that he pinion and spur dont mesh.

No strange noise? wich motor turns/pinion/spur?

yeah i have, took it out and re built it back up

no strange noise just the motor going round, am using a fusion 13.5 combo
with 80 spur and 28t pinion

Another motor to try ?

Diff bolt ok?

just tried another esc and motor to the same affect

in what way? it will tighten up when its too tight it makes a strange farting noise

OK, now I now it´s an internal problem.

When you turn one wheel the other turns in the opposite direction?
If it does, do you hear a "clean" or a crappy noise?

they both turn the same way

Sorry if you think I make you loos your time, I mean I don´t know if this is your fist car or you are a skilled mechanic

both wheels turn in the same direction?

this is my first car, when i turn one wheel by hand the other turns in the same direction

Try this, take the car from the rear. while you have the spur stopped with one hand, turn one rear wheel. they still turn in the same direction?

is the idler gear ok?

when i do that, they spin in opposite directions,

When you rebuilt the diff did you back the diff screw off too much. You should just be able to turn the diff with two hex drivers in the drive cups. If it moved too easily then your diff is too loose.

so your diff works right. It will be nice if you take your transmission out and inspect the gears. while you take the diff gear, the outdrives turn in opposite directions too.

Mace could be right, may be the idler gear is worn out and when you pull the throttle, all the power is lost becuase of this.

i tightened it up when it was back in the car and backed it off 1/4 of a turn

is that the cog in the middle of the diff case? if so its fine

The 1/4 turn is only a suggested starting point. You fine tune it till you can only just with moderate force move the diff with hex drives in the cups.

so with the diff in my hand i put hex drives in each cup and try turn the diff with my fingers? so i can just move it?

Yes. You should just be able to turn it.
This is from another forum on madrats
When screwing the diff, I screw it firmly until it bites and shows resistance. I then turn it back ¼ turn. I test it by popping 2 hex drivers in the drive cups, and try to spin the centre diff wheel. If I can move it I then tighten the screws up. Be careful though, as a ball diff should still move if you give it excessive force, so just a good firm attempt to twist it will be enough.

whilst i have it in pieces do you think its worth changing the idler gear at the same time?

If its got signs of excessive wear and you,ve got a spare you may as well.

i looked at it earlier when i took it all apart and it looked to have no damage, will double check it all and let you know how i get on,

cheers for all the help guys

Keep us informed ¡¡ :thumbsup:

i stripped down the diff and transmission and gave it all a good de grease, when i took out the thrust bearing it was a little crushed and only had 5 balls in it?? so i replaced that greased it all back up and put it back together

now its all working again :)

thanks for all your help its much appreciated

How I check diffs whilst in car is to tighten the slipper all the way and then hold one wheel and the spur and try and turn the other wheel. If it turns easy then you diff is loose. Should be hard to turn.