Almost no power to the rear wheels... Hmm?

[Damnir]

Wondering if someone can shed some light on my situation. I've noticed after playing with two full battery packs today, the rear wheels have no oomph. I changed the rear diff fluid to 500k, and it seemed to be working better than ever at first.

I was playing in loose snow, realized there's no spin at the rear unless it's full pin. If I hold the front of the truck off the ground and accelerate, I can feel it trying to push, but there's almost no oomph.

Would this be a clutch related issue? Nothing is missing in the driveline, ie; set screw. No weird clicking or binding, just not familiar with this slipper clutch. My other trucks have center diffs.

[cmbscx10]

I have to ask. Is it faster in reverse?

I have read that the slipper in the kit version being aluminum doesn't hold up long. Take off your spur cover and check that. Ive never run an aluminum slipper plate but i would think it would last longer than a paper disc.

The RTR manual states to have 3mm of exposed thread for a starting point while the Kit manual states to have 2mm. You could also try cranking the slipper nut all the way down (compressing the spring all the way) but don't jump it or anything. You just want to see if the slipper needs adjusting.

[Damnir]

The truck will almost launch itself off the ground in reverse. When I built the transmission/clutch, I did what my book said, which was to leave 2mm exposed. I also replaced the plastic spacer on the spur with a bearing. If you think I should tighten it a bit more, then I can try this... My kit did come with the aluminum/silver plates, I had seen others receiving red ones but I thought they were advised not to use them?

Thanks for the response... If anyone has any other ideas, please share. I don't feel like wrenching on the truck again this minute since it's all I've been doing since I got it!

[cmbscx10]

It should "launch itself off the ground" in Forward. If you have more power in reverse than forward then your motor needs to be reversed A & C swapped. I know the Tekin RX8 doesn't allow you to swap A & C but my MM2 does. Not sure what ESC you have.

[Fordfreak95]

You have something wrong mechanically. If your front tires are spinning & your rears aren't then you have a sheared pin or a broken something someplace. This rig is not like a center diff. set up. I would start with the output of the tranny to the driveshaft. Make sure the pin is there and not sheared in two. I sheared mine in two on my first run. If thats not it then move down to the rear diff. Pull the cover and take a look.

[Damnir]

Nothing is sheared... When I lift the front end and drag the car forward all four wheels spin. My motor wires are not backwards, they are color coded from Leopard / Hobbywing. I had to reverse the motor polarity via ESC settings when I purchased it because the AX-3 transmitter was glitchy when I tried to use it's option/feature.

I am only leaning on the slipper because it's the only piece I am not 100% familiar with, everything else is common to other 1:8 scale trucks. Like I said, the truck was fine for 3-4 battery packs, then I noticed it didn't seem to be rooster tailing as much snow from the rear. I pulled it on asphalt, lifted the front end and pinned it. The truck is trying to move, but not much. If I do it with the front end on the ground and the rear lifted, it's almost impossible to hold the truck in position.

Like I said, you can feel the truck is trying to push a little bit, it's not disconnected from the drive live in any way. My gut says it's slipping too much... Doesn't feel like a diff problem.

[Damnir]

Uploading a video as we speak...

[Damnir]

Uploaded a video, follow this link:

http://s45.photobucket.com/user/damn...o5ois.mp4.html

Thanks for the feedback fellas! (Oh, and ladies..)

[avted]

I don't think the slipper would have any bearing on this, and there's no center diff. As a previous poster said, something seems to be wrong somewhere between the rear tranny output to the rear wheels. Could be partially stripped wheel hubs/adapters that slip when they are driven by the drivetrain, but catch when the wheels are driven instead (engages the opposite side of the hub/hex) -- or some other one-way effect.

[avted]

Could be something binding in the rear drivetrain, too. Your video upload is not very clear (looks over-compressed).

[Damnir]

Photobucket only allows this size/format.. it automatically adjusts it. Not much else I can do to make it look better. I'll play with the slipper clutch tomorrow night when I feel like making a mess again.. There has to be a reason! It's clearly not in plain sight.

[Rjohn929]

I'm going to agree that your ESC is not wired correctly and you should switch 2 of the wires. It doesn't matter what 2 you switch as it is not sensored then reverse your radio. Humor me and try it before you say everything is right.

[Damnir]

Originally Posted by Rjohn929

I'm going to agree that your ESC is not wired correctly and you should switch 2 of the wires. It doesn't matter what 2 you switch as it is not sensored then reverse your radio. Humor me and try it before you say everything is right.

I'll give this a try, but first, I went ahead and tightened my slipper clutch nut. Works 100% better... I followed the book at 2mm exposed, I now have a little more and it's pushing really hard with the front tires off the ground and leaning on my leg. I had about 3 1/2 threads showing before, I'd say there's about 5 now.

In regards to those wires... I really never read into what the 3 colors are. Which two should I switch? I have the usual blue/orange/yellow.

[Rjohn929]

Any 2 wires will reverse the motor. Maybe it was just the slipper? I have about 2mm showing on mine and I don't think it's slipped yet. Is yours faster in reverse?

[Damnir]

Originally Posted by Rjohn929

Any 2 wires will reverse the motor. Maybe it was just the slipper? I have about 2mm showing on mine and I don't think it's slipped yet. Is yours faster in reverse?

I'll be honest, I rarely ever use reverse.. I only backup 1-2 foot, which usually results in a slight hop. I have probably said numerous times that I feel this truck is slow for 5S / 2000kv. Maybe you're right about the wires. I honestly thought it would be more complicated than just switching any two!

[Rjohn929]

Nope, sensorless is a piece of cake. That motor has a ton of power, Maybe even go bigger on the pinion to get some more speed.

[Damnir]

Originally Posted by Rjohn929

Nope, sensorless is a piece of cake. That motor has a ton of power, Maybe even go bigger on the pinion to get some more speed.

I've got a 17/18/19t pinions in tomorrow. As well as a few other goodies. I know my 5S/2000kv setup on my MT4 is insane, I have to turn the throttle trim down to 60%.

This might sound like a silly question, but why would it matter if the motor is turning one way or the other? Is it not as powerful running both directions? I honestly never put any thought into this before.

[Rjohn929]

Not the motor the ESC. I thought maybe your forward was actually the ESC's reverse. I run a 17t with my tekin 4038 2250. It temps at about 130 so I might try an 18. You might be able to get away with a 20 or 21 pinion.

[Damnir]

Originally Posted by Rjohn929

Not the motor the ESC. I thought maybe your forward was actually the ESC's reverse. I run a 17t with my tekin 4038 2250. It temps at about 130 so I might try an 18. You might be able to get away with a 20 or 21 pinion.

I have programming cards for my ESCs, one of the options is to flip motor polarity. When I first hooked up all the electronics, it was backwards. I tried using the switch on the transmitter and it made the truck go haywire and take off. I put it back, changed the option on the ESC and everything was smooth afterwards. Should I look into this more, or does it sound like everything is fine?

I've only been playing with RC for about a year and some change, so I am always eager to learn from anyone willing to share their opinions.

Thank you!

[Rjohn929]

Try setting the ESC to foward only and see if it still goes foward. It may be backwards. I think it went haywire and took off because the throttle trim was not centered when the transmitter was bound causing it to take off when you switched it.